1
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Zhong L, Zhang Y, Wang X, Zhu T, Mao SX. Atomic-scale observation of nucleation- and growth-controlled deformation twinning in body-centered cubic nanocrystals. Nat Commun 2024; 15:560. [PMID: 38228646 PMCID: PMC10791697 DOI: 10.1038/s41467-024-44837-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/04/2024] [Indexed: 01/18/2024] Open
Abstract
Twinning is an essential mode of plastic deformation for achieving superior strength and ductility in metallic nanostructures. It has been generally believed that twinning-induced plasticity in body-centered cubic (BCC) metals is controlled by twin nucleation, but facilitated by rapid twin growth once the nucleation energy barrier is overcome. By performing in situ atomic-scale transmission electron microscopy straining experiments and atomistic simulations, we find that deformation twinning in BCC Ta nanocrystals larger than 15 nm in diameter proceeds by reluctant twin growth, resulting from slow advancement of twinning partials along the boundaries of finite-sized twin structures. In contrast, reluctant twin growth can be obviated by reducing the nanocrystal diameter to below 15 nm. As a result, the nucleated twin structure penetrates quickly through the cross section of nanocrystals, enabling fast twin growth via facile migration of twin boundaries leading to large uniform plastic deformation. The present work reveals a size-dependent transition in the nucleation- and growth-controlled twinning mechanism in BCC metals, and provides insights for exploiting twinning-induced plasticity and breaking strength-ductility limits in nanostructured BCC metals.
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Affiliation(s)
- Li Zhong
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, China
| | - Yin Zhang
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Xiang Wang
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ting Zhu
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Scott X Mao
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA.
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2
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Wang Q, Yang H, Zuo X, Wang Y, Yao J. High-Throughput Preparation and Characterization of ZrMoTaW Refractory Multi-Principal Element Alloy Film. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8546. [PMID: 36500044 PMCID: PMC9739928 DOI: 10.3390/ma15238546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/27/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
In this work, high-throughput screening technology is applied to four-member refractory multi-principal element alloys (RMPEAs) films with high W content. The exploration of refractory metals such as W is strictly limited by the high melting temperature in this work; a multi-gradient deposition method was introduced to overcome this obstacle. By adjusting the power and distance from the target to the sample, component Zr11Mo11Ta25W53 with the best hardening performance was successfully obtained. The uniformity of the material library was analyzed from the perspectives of phase structure and micromorphology. With the help of Hume-Rothery theory and XRD analysis, it is shown that the film has a stable bcc structure. It is believed that film uniformity, nanoscale size, preferential orientation, surface roughness, and solution mechanism are the pivotal factors to improve hardness performance, especially for high W components. The hardness and modulus of elasticity can reach 20 GPa and 300 GPa, respectively, and the H/Er and H3/Er2 values are 0.067 and 0.065, showing the best wear resistance in many samples.
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Affiliation(s)
- Qiannan Wang
- School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Hongwang Yang
- School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Xiaojiao Zuo
- School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Yinxiao Wang
- School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Jiahao Yao
- Beijing Institute of Technology Chongqing Innovation Center, Chongqing 401120, China
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3
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Tseng KK, Huang HH, Wang WR, Yeh JW, Tsai CW. Edge-dislocation-induced ultrahigh elevated-temperature strength of HfMoNbTaW refractory high-entropy alloys. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2022; 23:642-654. [PMID: 36277504 PMCID: PMC9586648 DOI: 10.1080/14686996.2022.2129444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/10/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Over 150 refractory high-entropy alloys (RHEAs) have been proposed in the last decade. Early alloys such as MoNbTaW and MoNbTaVW still show an unparalleled yield strength of approximately 400 MPa at 1600°C. However, RHEAs with even elevated high-temperature strength are necessary in aerospace vehicles and nuclear reactors to cope with advanced technology in the future. Here, solid-solution strengthening calculation and melting point prediction are combined to design single-phase RHEA for attaining ultrahigh strength at 1600°C. The results show that Hf0.5MoNbTaW and HfMoNbTaW alloys after fully homogeneous treatment at 2100°C for 2 h reveal a homogenous body-centered cubic phase. HfMoNbTaW alloy exhibits a yield strength of 571 MPa at 1600°C, much higher than that of MoNbTaVW (477 MPa). It is found that a plateau of strength occurs from 800°C to 1200°C, which is important for raising the strength level of RHEAs at high temperatures. This strengthening mechanism is explained with the change of deformation mode from screw to edge dislocations, which contributes an edge-dislocation-induced strength. A similar alloy design strategy could be applied to develop more RHEAs with an ultrahigh strength level.
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Affiliation(s)
- Ko-Kai Tseng
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC
- High Entropy Materials Center, National Tsing Hua University, Hsinchu, Taiwan, ROC
| | - Hao-Hsuan Huang
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC
| | - Woei-Ren Wang
- Department of Additive Manufacturing Materials & Applications, Division of Metallic Materials Research, Material and Chemical Research Laboratories, Industrial Technology Research Institute, Tainan, Taiwan, ROC
| | - Jien-Wei Yeh
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC
- High Entropy Materials Center, National Tsing Hua University, Hsinchu, Taiwan, ROC
| | - Che-Wei Tsai
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC
- High Entropy Materials Center, National Tsing Hua University, Hsinchu, Taiwan, ROC
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4
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Relative mobility of screw versus edge dislocations controls the ductile-to-brittle transition in metals. Proc Natl Acad Sci U S A 2021; 118:2110596118. [PMID: 34493676 DOI: 10.1073/pnas.2110596118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 08/09/2021] [Indexed: 11/18/2022] Open
Abstract
Body-centered cubic metals including steels and refractory metals suffer from an abrupt ductile-to-brittle transition (DBT) at a critical temperature, hampering their performance and applications. Temperature-dependent dislocation mobility and dislocation nucleation have been proposed as the potential factors responsible for the DBT. However, the origin of this sudden switch from toughness to brittleness still remains a mystery. Here, we discover that the ratio of screw dislocation velocity to edge dislocation velocity is a controlling factor responsible for the DBT. A physical model was conceived to correlate the efficiency of Frank-Read dislocation source with the relative mobility of screw versus edge dislocations. A sufficiently high relative mobility is a prerequisite for the coordinated movement of screw and edge segments to sustain dislocation multiplication. Nanoindentation experiments found that DBT in chromium requires a critical mobility ratio of 0.7, above which the dislocation sources transition from disposable to regeneratable ones. The proposed model is also supported by the experimental results of iron, tungsten, and aluminum.
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5
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Chen Z, Paul B, Majumdar S, Okamoto NL, Kishida K, Inui H, Otani S. Room-temperature deformation of single crystals of ZrB 2 and TiB 2 with the hexagonal AlB 2 structure investigated by micropillar compression. Sci Rep 2021; 11:14265. [PMID: 34253780 PMCID: PMC8275602 DOI: 10.1038/s41598-021-93693-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/29/2021] [Indexed: 02/06/2023] Open
Abstract
The plastic deformation behavior of single crystals of two transition-metal diborides, ZrB2 and TiB2 with the AlB2 structure has been investigated at room temperature as a function of crystal orientation and specimen size by micropillar compression tests. Although plastic flow is not observed at all for their bulk single crystals at room temperature, plastic flow is successfully observed at room temperature by the operation of slip on {1[Formula: see text]00}<11[Formula: see text]3> in ZrB2 and by the operation of slip on {1[Formula: see text]00}<0001> and {1[Formula: see text]00}<11[Formula: see text]0> in TiB2. Critical resolve shear stress values at room temperature are very high, exceeding 1 GPa for all observed slip systems; 3.01 GPa for {1[Formula: see text]00}<11[Formula: see text]3> slip in ZrB2 and 1.72 GPa and 5.17 GPa, respectively for {1[Formula: see text]00}<0001> and {1[Formula: see text]00}<11[Formula: see text]0> slip in TiB2. The identified operative slip systems and their CRSS values are discussed in comparison with those identified in the corresponding bulk single crystals at high temperatures and those inferred from micro-hardness anisotropy in the early studies.
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Affiliation(s)
- Zhenghao Chen
- Center for Elements Strategy Initiative for Structure Materials (ESISM), Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Bhaskar Paul
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Sanjib Majumdar
- High Temperature Materials Development Section, Materials Processing and Corrosion Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Norihiko L Okamoto
- Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Kyosuke Kishida
- Center for Elements Strategy Initiative for Structure Materials (ESISM), Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Haruyuki Inui
- Center for Elements Strategy Initiative for Structure Materials (ESISM), Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Shigeki Otani
- Research Center for Functional Materials, National Institute for Materials Science, 1-1, Namiki, Tsukuba, Ibaraki, 305-0044, Japan
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6
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Zhang Q, Huang R, Zhang X, Cao T, Xue Y, Li X. Deformation Mechanisms and Remarkable Strain Hardening in Single-Crystalline High-Entropy-Alloy Micropillars/Nanopillars. NANO LETTERS 2021; 21:3671-3679. [PMID: 33756077 DOI: 10.1021/acs.nanolett.1c00444] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
There have been very limited studies on plastic deformation mechanisms in single-crystalline high-entropy alloys (HEAs) with body-centered cubic (BCC) phases. We performed in situ uniaxial compression on single-crystalline BCC AlCrFeCoNi micropillars/nanopillars with three orientations (including [100], [110], and [111]) and diameters of 270-1583 nm, inside a scanning electron microscope. The experimental results showed the significant size effects on yield/flow stress and the remarkable strain hardening in these HEA micropillars/nanopillars. Especially, HEA micropillars/nanopillars with ⟨100⟩ orientation exhibited higher strain hardening exponents than BCC pure metals and Al0.7CrCoFeNi counterparts. A combination of transmission electron microscopy observations and large-scale atomistic simulations revealed that dislocation slip, reaction, tangling and accumulation, and solid solution effects are responsible for the observed size effects on yield/flow stress and remarkable strain hardening, but these dislocation mechanisms are dependent on nanopillar orientation. Our present study sheds light on the underlying deformation mechanisms in BCC HEA single crystals.
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Affiliation(s)
- Qian Zhang
- Center for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Ruirui Huang
- Center for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Xuan Zhang
- Center for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Tangqing Cao
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yunfei Xue
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaoyan Li
- Center for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
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7
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Kishida K, Maruyama T, Fukuyama T, Inui H. Micropillar compression deformation of single crystals of α-Nb 5Si 3 with the tetragonal D8 l structure. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2021; 21:805-816. [PMID: 33488298 PMCID: PMC7801114 DOI: 10.1080/14686996.2020.1855065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
The plastic deformation behavior of single crystals of α-Nb5Si3 with the tetragonal D8 l structure has been investigated by micropillar compression at room temperature as a function of crystal orientation and specimen size. Three slip systems, (001)<010>, {110}<1 1 - 0> and {0 1 - 1}<111>, are found to be operative in micropillar specimens of α-Nb5Si3 single crystals at room temperature, as in the case of isostructural Mo5SiB2. The CRSS values obtained for the three slip systems are extremely high above 2.0 GPa and exhibit the 'smaller is stronger' trend, which can be approximated by the inverse power-law relationship. The fracture toughness evaluated by single-cantilever bend testing of a chevron-notched micro-beam specimen is 1.79 MPa m1/2, which is considerably lower than that (2.43 MPa m1/2) reported for isostructural Mo5SiB2. The selection for the dissociation schemes and possible glide planes for dislocations of the three slip systems is discussed based on generalized stacking fault energy (GSFE) curves theoretically calculated by first-principles calculations.
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Affiliation(s)
- Kyosuke Kishida
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Japan
- Center for Elements Strategy Initiative for Structural Materials (ESISM), Kyoto University, Sakyo-ku, Japan
| | - Takuto Maruyama
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Japan
| | - Takayoshi Fukuyama
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Japan
| | - Haruyuki Inui
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Japan
- Center for Elements Strategy Initiative for Structural Materials (ESISM), Kyoto University, Sakyo-ku, Japan
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8
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Kishida K, Fukuyama T, Maruyama T, Inui H. Room temperature deformation of single crystals of Ti 5Si 3 with the hexagonal D8 8 structure investigated by micropillar compression tests. Sci Rep 2020; 10:17983. [PMID: 33093506 PMCID: PMC7581531 DOI: 10.1038/s41598-020-75007-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/08/2020] [Indexed: 11/14/2022] Open
Abstract
Micropillar compression tests of Ti5Si3 single crystals were conducted at room temperature as a function of loading axis orientation and specimen size in order to investigate their room temperature plastic deformation behavior. Plastic flow by the operation of three deformation modes, {1[Formula: see text]00}[0001], {2[Formula: see text][Formula: see text]2} < 2[Formula: see text][Formula: see text][Formula: see text] > and {1[Formula: see text]01} < 2[Formula: see text][Formula: see text][Formula: see text] > slip were observed in [2[Formula: see text]05]-, [0001]- and [4[Formula: see text][Formula: see text]0]-oriented micropillar specimens deformed at room temperature, respectively. The CRSS values were evaluated to be very high above 2.7 GPa and were confirmed to increase up to about 6 GPa with the decrease in the specimen size. The fracture toughness values are evaluated to be 0.45 MPa m1/2 (notch plane // (0001)) and 0.73 MPa m1/2 (notch plane //(1[Formula: see text]00)) based on the results of micro-cantilever bend tests of chevron-notched specimens. The fracture toughness values are considerably lower than those for D8l-Mo5SiB2 and D8l-Nb5Si3 evaluated by the same method, indicating the inherent brittleness of binary Ti5Si3 compared to the other transition-metal silicides of the TM5Si3 type (TM: transition-metal).
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Affiliation(s)
- Kyosuke Kishida
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
- Center for Elements Strategy Initiative for Structural Materials (ESISM), Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Takayoshi Fukuyama
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Takuto Maruyama
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Haruyuki Inui
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
- Center for Elements Strategy Initiative for Structural Materials (ESISM), Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
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9
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Unusual activated processes controlling dislocation motion in body-centered-cubic high-entropy alloys. Proc Natl Acad Sci U S A 2020; 117:16199-16206. [PMID: 32601202 PMCID: PMC7368262 DOI: 10.1073/pnas.1919136117] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atomistic simulations of dislocation mobility reveal that body-centered cubic (BCC) high-entropy alloys (HEAs) are distinctly different from traditional BCC metals. HEAs are concentrated solutions in which composition fluctuation is almost inevitable. The resultant inhomogeneities, while locally promoting kink nucleation on screw dislocations, trap them against propagation with an appreciable energy barrier, replacing kink nucleation as the rate-limiting mechanism. Edge dislocations encounter a similar activated process of nanoscale segment detrapping, with comparable activation barrier. As a result, the mobility of edge dislocations, and hence their contribution to strength, becomes comparable to screw dislocations.
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10
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Liu W, Liu Y, Cheng Y, Chen L, Yu L, Yi X, Duan H. Unified Model for Size-Dependent to Size-Independent Transition in Yield Strength of Crystalline Metallic Materials. PHYSICAL REVIEW LETTERS 2020; 124:235501. [PMID: 32603175 DOI: 10.1103/physrevlett.124.235501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
Size-dependent yield strength is a common feature observed in miniaturized crystalline metallic samples, and plenty of studies have been conducted in experiments and numerical simulations to explore the underlying mechanism. However, the transition in yield strength from bulklike to size-affected behavior has received less attention. Here a unified theoretical model is proposed to probe the yield strength of crystalline metallic materials with sample size from nanoscale to macroscale. We show that the transition in yield strength versus size can be fully explained by the competition between the stresses required for dislocation source activation and dislocation motion, which is regulated by dislocation density, irradiation defect, grain boundary, and so on. Based on various grain boundary densities, the extended Hall-Petch relation, incorporated into the unified model, captures the reverse size effect for polycrystalline samples. The proposed model predictions agree well with reported experimental measurements of various specimens, including the prestrained nickel, irradiated copper, ultrafine grain tungsten, and so on.
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Affiliation(s)
- Wenbin Liu
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Ying Liu
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Yangyang Cheng
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Lirong Chen
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Long Yu
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Xin Yi
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Huiling Duan
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
- CAPT, HEDPS, and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China
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Zhang X, Ye H, Huang JC, Liu T, Lin P, Wu Y, Tsai M, Liao Y, Jang JSC. Nano-Scaled Creep Response of TiAlV Low Density Medium Entropy Alloy at Elevated Temperatures. MATERIALS (BASEL, SWITZERLAND) 2019; 13:E36. [PMID: 31861768 PMCID: PMC6982153 DOI: 10.3390/ma13010036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 11/25/2022]
Abstract
A low density, medium entropy alloy (LD-MEA) Ti33Al33V34 (4.44 g/cm3) was successfully developed. The microstructure was found to be composed of a disordered body-centered-cubic (BCC) matrix and minor ordered B2 precipitates based on transmission electron microscopy characterization. Equilibrium and non-equilibrium modeling, simulated using the Calphad approach, were applied to predict the phase constituent. Creep behavior of {110} grains at elevated temperatures was investigated by nanoindentation and the results were compared with Cantor alloy and Ti-6Al-4V alloy. Dislocation creep was found to be the dominant mechanism. The decreasing trend of hardness in {110} grains of BCC TiAlV is different from that in {111} grains of face-centered-cubic (FCC) Cantor alloy due to the different temperature-dependence of Peierls stress in these two lattice structures. The activation energy value of {110} grains was lower than that of {111} grains in FCC Cantor alloy because of the denser atomic stacking in FCC alloys. Compared with conventional Ti-6Al-4V alloy, TiAlV possesses considerably higher hardness and specific strength (63% higher), 83% lower creep displacement at room temperature, and 50% lower creep strain rate over the temperature range from 500 to 600 °C under the similar 1150 MPa stress, indicating a promising substitution for Ti-6Al-4V alloy as structural materials.
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Affiliation(s)
- Xiangkai Zhang
- Department of Materials Science & Engineering, Hong Kong Institute for Advanced Study, City University of Hong Kong, Kowloon, Hong Kong;
| | - Hanting Ye
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (H.Y.); (T.L.); (P.L.); (Y.W.); (M.T.)
| | - Jacob C. Huang
- Department of Materials Science & Engineering, Hong Kong Institute for Advanced Study, City University of Hong Kong, Kowloon, Hong Kong;
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (H.Y.); (T.L.); (P.L.); (Y.W.); (M.T.)
| | - Taiyou Liu
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (H.Y.); (T.L.); (P.L.); (Y.W.); (M.T.)
| | - Pinhung Lin
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (H.Y.); (T.L.); (P.L.); (Y.W.); (M.T.)
| | - Yaocheng Wu
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (H.Y.); (T.L.); (P.L.); (Y.W.); (M.T.)
| | - Mintsang Tsai
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (H.Y.); (T.L.); (P.L.); (Y.W.); (M.T.)
| | - Yuchin Liao
- Department of Mechanical Engineering, Institute of Materials Science and Engineering, National Central University, Chung-Li 32001, Taiwan; (Y.L.); (J.S.C.J.)
| | - Jason S. C. Jang
- Department of Mechanical Engineering, Institute of Materials Science and Engineering, National Central University, Chung-Li 32001, Taiwan; (Y.L.); (J.S.C.J.)
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12
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Review of Size Effects during Micropillar Compression Test: Experiments and Atomistic Simulations. CRYSTALS 2019. [DOI: 10.3390/cryst9110591] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The micropillar compression test is a novel experiment to study the mechanical properties of materials at small length scales of micro and nano. The results of the micropillar compression experiments show that the strength of the material depends on the pillar diameter, which is commonly termed as size effects. In the current work, first, the experimental observations and theoretical models of size effects during micropillar compression tests are reviewed in the case of crystalline metals. In the next step, the recent computer simulations using molecular dynamics are reviewed as a powerful tool to investigate the micropillar compression experiment and its governing mechanisms of size effects.
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13
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Superior plasticity stability and excellent strength in Ti-55531 alloy micropillars via harmony slip in nanoscale α/β phases. Sci Rep 2019; 9:5075. [PMID: 30911027 PMCID: PMC6433921 DOI: 10.1038/s41598-019-41574-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 02/25/2019] [Indexed: 11/23/2022] Open
Abstract
Excellent stability of plasticity and high strength are acquired in Ti55531 alloy micropillars via introducing a high density of deformable nanoscale α phase into a β matrix. The yield strength of the pillars is as high as 2.26 GPa irrespective of pillar sizes ranging from 6 to 0.3 μm, which is high enough to activate dislocation slip both in ductile α precipitates and the β matrix. The harmony slip model was proposed to interpret slip transmission between the nanoscale α phase and the divided β matrix, and both α and β accommodate their individual plasticity during compression. This results in an excellent combination of high strength and stable plasticity in Ti55531 alloy micron-to submicron pillars. The results highlight the novel strengthening and toughening mechanisms of nanostructured alloys and a specific type of microstructure that exhibits stable plasticity for nano/microdevices.
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14
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On the Critical Resolved Shear Stress and its Importance in the Fatigue Performance of Steels and other Metals with Different Crystallographic Structures. METALS 2018. [DOI: 10.3390/met8110883] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study deals with the numerical estimation of the fatigue life represented in the form of strength-life (S-N, or Wöhler) curves of metals with different crystallographic structures, namely body-centered cubic (BCC) and face-centered cubic (FCC). Their life curves are determined by analyzing the initiation of a short crack under the influence of microstructure and subsequent growth of the long crack, respectively. Micro-models containing microstructures of the materials are set up by using the finite element method (FEM) and are applied in combination with the Tanaka-Mura (TM) equation in order to estimate the number of cycles required for the crack initiation. The long crack growth analysis is conducted using the Paris law. The study shows that the crystallographic structure is not the predominant factor that determines the shape and position of the fatigue life curve in the S-N diagram, but it is rather the material parameter known as the critical resolved shear stress (CRSS). Even though it is an FCC material, the investigated austenitic stainless steel AISI 304 shows an untypically high fatigue limit (208 MPa), which is higher than the fatigue limit of the BCC vanadium-based micro-alloyed forging steel AISI 1141 (152 MPa).
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15
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Dupraz M, Beutier G, Cornelius TW, Parry G, Ren Z, Labat S, Richard MI, Chahine GA, Kovalenko O, De Boissieu M, Rabkin E, Verdier M, Thomas O. 3D Imaging of a Dislocation Loop at the Onset of Plasticity in an Indented Nanocrystal. NANO LETTERS 2017; 17:6696-6701. [PMID: 29052998 DOI: 10.1021/acs.nanolett.7b02680] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Structural quality and stability of nanocrystals are fundamental problems that bear important consequences for the performances of small-scale devices. Indeed, at the nanoscale, their functional properties are largely influenced by elastic strain and depend critically on the presence of crystal defects. It is thus of prime importance to be able to monitor, by noninvasive means, the stability of the microstructure of nano-objects against external stimuli such as mechanical load. Here we demonstrate the potential of Bragg coherent diffraction imaging for such measurements, by imaging in 3D the evolution of the microstructure of a nanocrystal exposed to in situ mechanical loading. Not only could we observe the evolution of the internal strain field after successive loadings, but we also evidenced a transient microstructure hosting a stable dislocation loop. The latter is fully characterized from its characteristic displacement field. The mechanical behavior of this small crystal is clearly at odds with what happens in bulk materials where many dislocations interact. Moreover, this original in situ experiment opens interesting possibilities for the investigation of plastic deformation at the nanoscale.
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Affiliation(s)
- M Dupraz
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - G Beutier
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - T W Cornelius
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
| | - G Parry
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - Z Ren
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
| | - S Labat
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
| | - M-I Richard
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
- ID01/ESRF , 71 Avenue des Martyrs, CS40220, F-38043 Grenoble Cedex 9, France
| | - G A Chahine
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - O Kovalenko
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology , 32000 Haifa, Israel
| | - M De Boissieu
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - E Rabkin
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology , 32000 Haifa, Israel
| | - M Verdier
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - O Thomas
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
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16
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Enhanced strength and temperature dependence of mechanical properties of Li at small scales and its implications for Li metal anodes. Proc Natl Acad Sci U S A 2016; 114:57-61. [PMID: 27994136 DOI: 10.1073/pnas.1615733114] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Most next-generation Li ion battery chemistries require a functioning lithium metal (Li) anode. However, its application in secondary batteries has been inhibited because of uncontrollable dendrite growth during cycling. Mechanical suppression of dendrite growth through solid polymer electrolytes (SPEs) or through robust separators has shown the most potential for alleviating this problem. Studies of the mechanical behavior of Li at any length scale and temperature are limited because of its extreme reactivity, which renders sample preparation, transfer, microstructure characterization, and mechanical testing extremely challenging. We conduct nanomechanical experiments in an in situ scanning electron microscope and show that micrometer-sized Li attains extremely high strengths of 105 MPa at room temperature and of 35 MPa at 90 °C. We demonstrate that single-crystalline Li exhibits a power-law size effect at the micrometer and submicrometer length scales, with the strengthening exponent of -0.68 at room temperature and of -1.00 at 90 °C. We also report the elastic and shear moduli as a function of crystallographic orientation gleaned from experiments and first-principles calculations, which show a high level of anisotropy up to the melting point, where the elastic and shear moduli vary by a factor of ∼4 between the stiffest and most compliant orientations. The emergence of such high strengths in small-scale Li and sensitivity of this metal's stiffness to crystallographic orientation help explain why the existing methods of dendrite suppression have been mainly unsuccessful and have significant implications for practical design of future-generation batteries.
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17
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Wheeler JM, Kirchlechner C, Micha JS, Michler J, Kiener D. The effect of size on the strength of FCC metals at elevated temperatures: annealed copper. PHILOSOPHICAL MAGAZINE (ABINGDON, ENGLAND) 2016; 96:3379-3395. [PMID: 28003795 PMCID: PMC5125415 DOI: 10.1080/14786435.2016.1224945] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 08/11/2016] [Indexed: 06/06/2023]
Abstract
As the length scale of sample dimensions is reduced to the micron and sub-micron scales, the strength of various materials has been observed to increase with decreasing size, a fact commonly referred to as the 'sample size effect'. In this work, the influence of temperature on the sample size effect in copper is investigated using in situ microcompression testing at 25, 200 and 400 °C in the SEM on vacuum-annealed copper structures, and the resulting deformed structures were analysed using X-ray μLaue diffraction and scanning electron microscopy. For pillars with sizes between 0.4 and 4 μm, the size effect was measured to be constant with temperature, within the measurement precision, up to half of the melting point of copper. It is expected that the size effect will remain constant with temperature until diffusion-controlled dislocation motion becomes significant at higher temperatures and/or lower strain rates. Furthermore, the annealing treatment of the copper micropillars produced structures which yielded at stresses three times greater than their un-annealed, FIB-machined counterparts.
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Affiliation(s)
- Jeffrey M. Wheeler
- Laboratory for Nanometallurgy, ETH Zürich, Zurich, Switzerland
- Laboratory for Mechanics of Materials and Nanostructures, Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland
| | - Christoph Kirchlechner
- Structure and Nano-/Micromechanics of Materials, Max-Planck-Institut fur Eisenforschung GmbH, Dusseldorf, Germany
- Department of Materials Physics, Montanuniversität Leoben, Leoben, Austria
| | - Jean-Sébastien Micha
- UMR CNRS-CEA SPrAM, Institute Nanosciences and Cryogenics, Université Grenoble Alpes, Grenoble, France
- CRG-IF BM32 Beamline at the European Synchrotron (ESRF), Grenoble, France
| | - Johann Michler
- Laboratory for Mechanics of Materials and Nanostructures, Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland
| | - Daniel Kiener
- Department of Materials Physics, Montanuniversität Leoben, Leoben, Austria
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18
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Okamoto NL, Fujimoto S, Kambara Y, Kawamura M, Chen ZMT, Matsunoshita H, Tanaka K, Inui H, George EP. Size effect, critical resolved shear stress, stacking fault energy, and solid solution strengthening in the CrMnFeCoNi high-entropy alloy. Sci Rep 2016; 6:35863. [PMID: 27775026 PMCID: PMC5075899 DOI: 10.1038/srep35863] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/05/2016] [Indexed: 11/09/2022] Open
Abstract
High-entropy alloys (HEAs) comprise a novel class of scientifically and technologically interesting materials. Among these, equatomic CrMnFeCoNi with the face-centered cubic (FCC) structure is noteworthy because its ductility and strength increase with decreasing temperature while maintaining outstanding fracture toughness at cryogenic temperatures. Here we report for the first time by single-crystal micropillar compression that its bulk room temperature critical resolved shear stress (CRSS) is ~33–43 MPa, ~10 times higher than that of pure nickel. CRSS depends on pillar size with an inverse power-law scaling exponent of –0.63 independent of orientation. Planar ½ < 110 > {111} dislocations dissociate into Shockley partials whose separations range from ~3.5–4.5 nm near the screw orientation to ~5–8 nm near the edge, yielding a stacking fault energy of 30 ± 5 mJ/m2. Dislocations are smoothly curved without any preferred line orientation indicating no significant anisotropy in mobilities of edge and screw segments. The shear-modulus-normalized CRSS of the HEA is not exceptionally high compared to those of certain concentrated binary FCC solid solutions. Its rough magnitude calculated using the Fleischer/Labusch models corresponds to that of a hypothetical binary with the elastic constants of our HEA, solute concentrations of 20–50 at.%, and atomic size misfit of ~4%.
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Affiliation(s)
- Norihiko L Okamoto
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan.,Center for Elements Strategy Initiative for Structure Materials (ESISM), Kyoto University, Kyoto 606-8501, Japan
| | - Shu Fujimoto
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Yuki Kambara
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Marino Kawamura
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Zhenghao M T Chen
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Hirotaka Matsunoshita
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Katsushi Tanaka
- Department of Mechanical Engineering, Kobe University, Nada-ku, Kobe 657-8501, Japan
| | - Haruyuki Inui
- Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan.,Center for Elements Strategy Initiative for Structure Materials (ESISM), Kyoto University, Kyoto 606-8501, Japan
| | - Easo P George
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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19
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Superior room-temperature ductility of typically brittle quasicrystals at small sizes. Nat Commun 2016; 7:12261. [PMID: 27515779 PMCID: PMC4990631 DOI: 10.1038/ncomms12261] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 06/15/2016] [Indexed: 11/16/2022] Open
Abstract
The discovery of quasicrystals three decades ago unveiled a class of matter that exhibits long-range order but lacks translational periodicity. Owing to their unique structures, quasicrystals possess many unusual properties. However, a well-known bottleneck that impedes their widespread application is their intrinsic brittleness: plastic deformation has been found to only be possible at high temperatures or under hydrostatic pressures, and their deformation mechanism at low temperatures is still unclear. Here, we report that typically brittle quasicrystals can exhibit remarkable ductility of over 50% strains and high strengths of ∼4.5 GPa at room temperature and sub-micrometer scales. In contrast to the generally accepted dominant deformation mechanism in quasicrystals—dislocation climb, our observation suggests that dislocation glide may govern plasticity under high-stress and low-temperature conditions. The ability to plastically deform quasicrystals at room temperature should lead to an improved understanding of their deformation mechanism and application in small-scale devices. Quasicrystals are typically stiff and hard, but also brittle in bulk form at room temperature. Here, authors observe ductile behaviour in quasicrystalline pillars of submicron diameter and provide evidence for dislocation-based plasticity at intermediate length scales and room temperature as an explanation.
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20
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Dislocation "Bubble-Like-Effect" and the Ambient Temperature Super-plastic Elongation of Body-centred Cubic Single Crystalline Molybdenum. Sci Rep 2016; 6:22937. [PMID: 26956918 PMCID: PMC4783708 DOI: 10.1038/srep22937] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/23/2016] [Indexed: 12/02/2022] Open
Abstract
With our recently developed deformation device, the in situ tensile tests of single crystal molybdenum nanowires with various size and aspect ratio were conducted inside a transmission electron microscope (TEM). We report an unusual ambient temperature (close to room temperature) super-plastic elongation above 127% on single crystal body-centred cubic (bcc) molybdenum nanowires with an optimized aspect ratio and size. A novel dislocation “bubble-like-effect” was uncovered for leading to the homogeneous, large and super-plastic elongation strain in the bcc Mo nanowires. The dislocation bubble-like-effect refers to the process of dislocation nucleation and annihilation, which likes the nucleation and annihilation process of the water bubbles. A significant plastic deformation dependence on the sample’s aspect ratio and size was revealed. The atomic scale TEM observations also demonstrated that a single crystal to poly-crystal transition and a bcc to face-centred cubic phase transformation took place, which assisted the plastic deformation of Mo in small scale.
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21
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Zou Y, Ma H, Spolenak R. Ultrastrong ductile and stable high-entropy alloys at small scales. Nat Commun 2015; 6:7748. [PMID: 26159936 PMCID: PMC4510962 DOI: 10.1038/ncomms8748] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 06/05/2015] [Indexed: 11/16/2022] Open
Abstract
Refractory high-entropy alloys (HEAs) are a class of emerging multi-component alloys, showing superior mechanical properties at elevated temperatures and being technologically interesting. However, they are generally brittle at room temperature, fail by cracking at low compressive strains and suffer from limited formability. Here we report a strategy for the fabrication of refractory HEA thin films and small-sized pillars that consist of strongly textured, columnar and nanometre-sized grains. Such HEA pillars exhibit extraordinarily high yield strengths of ∼10 GPa—among the highest reported strengths in micro-/nano-pillar compression and one order of magnitude higher than that of its bulk form—and their ductility is considerably improved (compressive plastic strains over 30%). Additionally, we demonstrate that such HEA films show substantially enhanced stability for high-temperature, long-duration conditions (at 1,100 °C for 3 days). Small-scale HEAs combining these properties represent a new class of materials in small-dimension devices potentially for high-stress and high-temperature applications. Refractory high-entropy alloys show promising mechanical properties at elevated temperatures, but are generally brittle at room temperature. Here, the authors observe an improved ductility and yield strength in high-entropy alloy micropillars consisting of nanometre-sized grains that also exhibit excellent thermal stability.
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Affiliation(s)
- Yu Zou
- Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, CH-8093 Zurich, Switzerland
| | - Huan Ma
- Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, CH-8093 Zurich, Switzerland
| | - Ralph Spolenak
- Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, CH-8093 Zurich, Switzerland
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22
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Wang J, Zeng Z, Weinberger CR, Zhang Z, Zhu T, Mao SX. In situ atomic-scale observation of twinning-dominated deformation in nanoscale body-centred cubic tungsten. NATURE MATERIALS 2015; 14:594-600. [PMID: 25751073 DOI: 10.1038/nmat4228] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/28/2015] [Indexed: 06/04/2023]
Abstract
Twinning is a fundamental deformation mode that competes against dislocation slip in crystalline solids. In metallic nanostructures, plastic deformation requires higher stresses than those needed in their bulk counterparts, resulting in the 'smaller is stronger' phenomenon. Such high stresses are thought to favour twinning over dislocation slip. Deformation twinning has been well documented in face-centred cubic (FCC) nanoscale crystals. However, it remains unexplored in body-centred cubic (BCC) nanoscale crystals. Here, by using in situ high-resolution transmission electron microscopy and atomistic simulations, we show that twinning is the dominant deformation mechanism in nanoscale crystals of BCC tungsten. Such deformation twinning is pseudoelastic, manifested through reversible detwinning during unloading. We find that the competition between twinning and dislocation slip can be mediated by loading orientation, which is attributed to the competing nucleation mechanism of defects in nanoscale BCC crystals. Our work provides direct observations of deformation twinning as well as new insights into the deformation mechanism in BCC nanostructures.
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Affiliation(s)
- Jiangwei Wang
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Zhi Zeng
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Christopher R Weinberger
- 1] Materials Science and Engineering Center, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA [2] Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Ze Zhang
- Department of Materials Science and Engineering and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China
| | - Ting Zhu
- 1] Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA [2] School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Scott X Mao
- 1] Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA [2] Department of Materials Science and Engineering and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China
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23
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Marichal C, Srivastava K, Weygand D, Van Petegem S, Grolimund D, Gumbsch P, Van Swygenhoven H. Origin of anomalous slip in tungsten. PHYSICAL REVIEW LETTERS 2014; 113:025501. [PMID: 25062203 DOI: 10.1103/physrevlett.113.025501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Indexed: 06/03/2023]
Abstract
Low-temperature deformation of body-centered cubic metals shows a significant amount of plastic slip on planes with low shear stresses, a phenomenon called anomalous slip. Despite progress in atomistic modeling of the consequences of complex stress states on dislocation mobility, the phenomenon of anomalous slip remained elusive. Using in situ Laue microdiffraction and discrete dislocation dynamics in micrometer sized tungsten single crystals, we demonstrate the occurrence of significant anomalous slip. It occurs as a consequence of cross kinks, topological configurations generated by prior dislocation interactions. This clearly identifies anomalous slip as a multidislocation process and not a property of isolated dislocations. The cross-kink mechanism also explains the ambiguous reporting of anomalous slip traces in the past and directs us to ways of including anomalous slip in continuum crystal plasticity formulations.
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Affiliation(s)
- C Marichal
- Materials Science and Simulation, NUM/ASQ, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and Neutrons and X-rays for Mechanics of Materials, IMX, École Polytechnique Fédérale de Lausanne, CH-1012 Lausanne, Switzerland
| | - K Srivastava
- Institute for Applied Materials IAM, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - D Weygand
- Institute for Applied Materials IAM, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - S Van Petegem
- Materials Science and Simulation, NUM/ASQ, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D Grolimund
- Beamline MicroXAS, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Gumbsch
- Institute for Applied Materials IAM, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany and Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstrasse 11, 79108 Freiburg, Germany
| | - H Van Swygenhoven
- Materials Science and Simulation, NUM/ASQ, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and Neutrons and X-rays for Mechanics of Materials, IMX, École Polytechnique Fédérale de Lausanne, CH-1012 Lausanne, Switzerland
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24
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Kiener D, Kaufmann P, Minor AM. Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing. ADVANCED ENGINEERING MATERIALS 2012; 14:960-967. [PMID: 23447712 PMCID: PMC3573867 DOI: 10.1002/adem.201200031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 04/11/2012] [Indexed: 06/01/2023]
Abstract
We present in situ transmission electron microscope tensile tests on focused ion beam fabricated single and multiple slip oriented Cu tensile samples with thicknesses in the range of 100-200 nm. Both crystal orientations fail by localized shear. While failure occurs after a few percent plastic strain and limited hardening in the single slip case, the multiple slip samples exhibit extended homogenous deformation and necking due to the activation of multiple dislocation sources in conjunction with significant hardening. The hardening behavior at 1% plastic strain is even more pronounced compared to compression samples of the same orientation due to the absence of sample taper and the interface to the compression platen. Moreover, we show for the first time that the strain rate sensitivity of such FIB prepared samples is an order of magnitude higher than that of bulk Cu.
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Affiliation(s)
- Daniel Kiener
- Department of Materials Physics, Montanuniversität Leoben, Jahnstraße 128700 Leoben, Austria
- National Center for Electron Microscopy, Lawrence Berkeley National Laboratory94720 Berkeley, CA, USA
| | - Petra Kaufmann
- Department of Materials Physics, Montanuniversität Leoben, Jahnstraße 128700 Leoben, Austria
| | - Andrew M. Minor
- National Center for Electron Microscopy, Lawrence Berkeley National Laboratory94720 Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California94720 Berkeley, CA, USA
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25
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Maaß R, Meza L, Gan B, Tin S, Greer JR. Ultrahigh strength of dislocation-free Ni3Al nanocubes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:1869-1875. [PMID: 22454244 DOI: 10.1002/smll.201102603] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Indexed: 05/31/2023]
Abstract
Individual Ni(3) Al nanocubes under pressure are investigated by comparing the compressive strength of both dislocation-free and irradiated Ni(3) Al nanocubes. The results are dicussed in light of the size-dependent and size-independent strength of face-centered cubic (fcc) nanocrystals in the framework of dislocation nucleation at free surfaces. This study sheds more light on the understanding of fundamental deformation mechanisms and size-affected strength in dislocation-free metallic nanocrystals.
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Affiliation(s)
- Robert Maaß
- California Institute of Technology, Division of Engineering and Applied Sciences, 1200 E California Blvd, Pasadena, CA 91125, USA.
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26
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Huang L, Li QJ, Shan ZW, Li J, Sun J, Ma E. A new regime for mechanical annealing and strong sample-size strengthening in body centred cubic molybdenum. Nat Commun 2011; 2:547. [DOI: 10.1038/ncomms1557] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 10/19/2011] [Indexed: 11/09/2022] Open
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27
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Gianola DS, Sedlmayr A, Mönig R, Volkert CA, Major RC, Cyrankowski E, Asif SAS, Warren OL, Kraft O. In situ nanomechanical testing in focused ion beam and scanning electron microscopes. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:063901. [PMID: 21721703 DOI: 10.1063/1.3595423] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The recent interest in size-dependent deformation of micro- and nanoscale materials has paralleled both technological miniaturization and advancements in imaging and small-scale mechanical testing methods. Here we describe a quantitative in situ nanomechanical testing approach adapted to a dual-beam focused ion beam and scanning electron microscope. A transducer based on a three-plate capacitor system is used for high-fidelity force and displacement measurements. Specimen manipulation, transfer, and alignment are performed using a manipulator, independently controlled positioners, and the focused ion beam. Gripping of specimens is achieved using electron-beam assisted Pt-organic deposition. Local strain measurements are obtained using digital image correlation of electron images taken during testing. Examples showing results for tensile testing of single-crystalline metallic nanowires and compression of nanoporous Au pillars will be presented in the context of size effects on mechanical behavior and highlight some of the challenges of conducting nanomechanical testing in vacuum environments.
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Affiliation(s)
- D S Gianola
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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