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Zhou Y, Yue H, Ma Z, Guo Z, Zhang J, Wang L, Yan G. Microstructure and Mechanical Properties of Ni-20Cr-Eu 2O 3 Composites Prepared by Vacuum Hot Pressing. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1473. [PMID: 36837102 PMCID: PMC9965499 DOI: 10.3390/ma16041473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/17/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Ni-20Cr-Eu2O3 composites were designed as new control rod materials and were synthesized from Ni, Cr, and Eu2O3 mixture powders via ball milling and vacuum hot pressing. During ball milling, Eu2O3 was fined, nano-crystallized, amorphized, and then dissolved into matrix. The effect of Eu2O3 content on the microstructure and mechanics was researched, and the corresponding mechanism was discussed. The relative densities, grain sizes, and microhardness increased when Eu2O3 content increased. According to the TEM observations, Eu2O3 particles showed a semi-coherent relationship with the matrix. The results of mechanical property testing showed that the ultimate tensile strength, yield strength, and elongation decreased with the Eu2O3 content increased. The maximum ultimate tensile strength, yield strength, and elongation were 741 MPa, 662 MPa, and 4%, respectively, with a 5 wt.% Eu2O3 addition. The experimental strengths were well matched with the theoretical values calculated by the strengthening mechanisms indicating that this method was highly effective for predicting the mechanical properties of Ni-20Cr-Eu2O3 composites.
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Affiliation(s)
- Yihong Zhou
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Corp., Ltd., Beijing 101407, China
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
- GRINM Resources and Environment Tech. Co., Ltd., Beijing 101407, China
- General Research Institute for Nonferrous Metal, Beijing 100088, China
| | - Huifang Yue
- Nuclear Power Institute of China, Science and Technology on Reactor System Design Technology Laboratory, Chengdu 610200, China
| | - Zhaohui Ma
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Corp., Ltd., Beijing 101407, China
- GRINM Resources and Environment Tech. Co., Ltd., Beijing 101407, China
- General Research Institute for Nonferrous Metal, Beijing 100088, China
| | - Zhancheng Guo
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
| | - Jiandong Zhang
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Corp., Ltd., Beijing 101407, China
- GRINM Resources and Environment Tech. Co., Ltd., Beijing 101407, China
- General Research Institute for Nonferrous Metal, Beijing 100088, China
| | - Lijun Wang
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Corp., Ltd., Beijing 101407, China
- GRINM Resources and Environment Tech. Co., Ltd., Beijing 101407, China
- General Research Institute for Nonferrous Metal, Beijing 100088, China
| | - Guoqing Yan
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Corp., Ltd., Beijing 101407, China
- GRINM Resources and Environment Tech. Co., Ltd., Beijing 101407, China
- General Research Institute for Nonferrous Metal, Beijing 100088, China
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Effect of High-Density Nanoparticles on Recrystallization and Texture Evolution in Ferritic Alloys. CRYSTALS 2019. [DOI: 10.3390/cryst9030172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ferritic alloys are important for nuclear reactor applications due to their microstructural stability, corrosion resistance, and favorable mechanical properties. Nanostructured ferritic alloys having a high density of Y-Ti-O rich nano-oxides (NOs < 5 nm) are found to be extremely stable at high temperatures up to ~1100 °C. This study serves to understand the effect of a high density of nano-particles on texture evolution and recrystallization mechanisms in ferritic alloys of 14YWT (14Cr-3W-0.4Ti-0.21Y-Fe wt %) having a high density of nano-particles and dispersion-free FeCrAl (13Cr-5.2Al-0.05Y-2Mo-0.2Si-1Nb wt %). In order to investigate the recrystallization mechanisms in these alloys, neutron diffraction, electron backscattered diffraction, and in situ and ex situ transmission electron microscopy have been utilized. It has been observed that even though the deformation textures of both the 14YWT and FeCrAl alloys evolved similarly, resulting in either the formation (in FeCrAl alloy) or increase (in 14YWT) in γ-fiber texture, the texture evolution during recrystallization is different. While FeCrAl alloy keeps its γ-fiber texture after recrystallization, 14YWT samples develop a ε-fiber as a result of annealing at 1100 °C, which can be attributed to the existence of NOs. In situ transmission electron microscopy annealing experiments on 14YWT show the combination and growth of the lamellar grains rather than nucleation; however, the recrystallization and growth kinetics are slower due to NOs compared to FeCrAl.
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Abstract
To lower the cost, Ti alloys fabricated by elemental powder metallurgy have been widely studied. High contents of oxygen and residual porosities are usually inevitable in as-sintered Ti alloys. Thus, rare earth elements are added to PM Ti alloys for scavenging of oxygen, increasing sintered density and strengthening the matrix. This paper reviews recent studies on the effects of rare earth elements (La and Y) on the densification behaviours, mechanical properties and high temperature oxidation resistance of PM Ti alloys. The improvement of room temperature ductility of PM Ti alloys through the addition of rare earth elements has been extensively confirmed. However, other benefits from rare earth additions depend largely on alloy compositions, processing parameters and environmental conditions.
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