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Fotopoulos V, O’Hern CS, Shattuck MD, Shluger AL. Modeling the Effects of Varying the Ti Concentration on the Mechanical Properties of Cu-Ti Alloys. ACS OMEGA 2024; 9:10286-10298. [PMID: 38463266 PMCID: PMC10918840 DOI: 10.1021/acsomega.3c07561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 03/12/2024]
Abstract
The mechanical properties of CuTi alloys have been characterized extensively through experimental studies. However, a detailed understanding of why the strength of Cu increases after a small fraction of Ti atoms are added to the alloy is still missing. In this work, we address this question using density functional theory (DFT) and molecular dynamics (MD) simulations with the modified embedded atom method (MEAM) interatomic potentials. First, we performed calculations of the uniaxial tension deformations of small bicrystalline Cu cells using DFT static simulations. We then carried out uniaxial tension deformations on much larger bicrystalline and polycrystalline Cu cells by using MEAM MD simulations. In bicrystalline Cu, the inclusion of Ti increases the grain boundary separation energy and the maximum tensile stress. The DFT calculations demonstrate that the increase in the tensile stress can be attributed to an increase in the local charge density arising from Ti. MEAM simulations in larger bicrystalline systems have shown that increasing the Ti concentration decreases the density of the stacking faults. This observation is enhanced in polycrystalline Cu, where the addition of Ti atoms, even at concentrations as low as 1.5 atomic (at.) %, increases the yield strength and elastic modulus of the material compared to pure Cu. Under uniaxial tensile loading, the addition of small amounts of Ti hinders the formation of partial Shockley dislocations in the grain boundaries of Cu, leading to a reduced level of local deformation. These results shed light on the role of Ti in determining the mechanical properties of polycrystalline Cu and enable the engineering of grain boundaries and the inclusion of Ti to improve degradation resistance.
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Affiliation(s)
- Vasileios Fotopoulos
- Department
of Physics and Astronomy, University College
London, Gower Street, London WC1E
6BT, U.K.
| | - Corey S. O’Hern
- Department
of Mechanical Engineering & Materials Science, Yale University, New Haven, Connecticut 06520, United States
- Department
of Physics, Yale University, New Haven, Connecticut 06520, United States
- Department
of Applied Physics, Yale University, New Haven, Connecticut 06520, United States
| | - Mark D. Shattuck
- Benjamin
Levich Institute and Physics Department, The City College of the City University of New York, New York, New York 10031, United States
| | - Alexander L. Shluger
- Department
of Physics and Astronomy, University College
London, Gower Street, London WC1E
6BT, U.K.
- WPI-Advanced
Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1
Katahira, Aoba-ku, Sendai 980-8577, Japan
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Ab initio modelling of intergranular fracture of nickel containing phosphorus: Interfacial excess properties. NUCLEAR MATERIALS AND ENERGY 2021. [DOI: 10.1016/j.nme.2021.101055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Mazalová M, Všianská M, Pavlů J, Šob M. The Effect of Vacancies on Grain Boundary Segregation in Ferromagnetic fcc Ni. NANOMATERIALS 2020; 10:nano10040691. [PMID: 32268587 PMCID: PMC7221896 DOI: 10.3390/nano10040691] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 11/16/2022]
Abstract
This work presents a comprehensive and detailed ab initio study of interactions between the tilt Σ5(210) grain boundary (GB), impurities X (X = Al, Si) and vacancies (Va) in ferromagnetic fcc nickel. To obtain reliable results, two methods of structure relaxation were employed: the automatic full relaxation and the finding of the minimum energy with respect to the lattice dimensions perpendicular to the GB plane and positions of atoms. Both methods provide comparable results. The analyses of the following phenomena are provided: the influence of the lattice defects on structural properties of material such as lattice parameters, the volume per atom, interlayer distances and atomic positions; the energies of formation of particular structures with respect to the standard element reference states; the stabilization/destabilization effects of impurities (in substitutional (s) as well as in tetragonal (iT) and octahedral (iO) interstitial positions) and of vacancies in both the bulk material and material with GBs; a possibility of recombination of Si(i)+Va defect to Si(s) one with respect to the Va position; the total energy of formation of GB and Va; the binding energies between the lattice defects and their combinations; impurity segregation energies and the effect of Va on them; magnetic characteristics in the presence of impurities, vacancies and GBs. As there is very little experimental information on the interaction between impurities, vacancies and GBs in fcc nickel, most of the present results are theoretical predictions, which may motivate future experimental work.
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Affiliation(s)
- Martina Mazalová
- Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic; (M.M.); (M.V.); (J.P.)
| | - Monika Všianská
- Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic; (M.M.); (M.V.); (J.P.)
- Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, CZ-616 62 Brno, Czech Republic
| | - Jana Pavlů
- Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic; (M.M.); (M.V.); (J.P.)
- Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, CZ-616 62 Brno, Czech Republic
| | - Mojmír Šob
- Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic; (M.M.); (M.V.); (J.P.)
- Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, CZ-616 62 Brno, Czech Republic
- Central European Institute of Technology, CEITEC MU, Masaryk University, Kamenice 753/5, CZ-625 00 Brno, Czech Republic
- Correspondence: or ; Tel.: +420-549-497-450
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