About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
|
Symposium
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High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond II
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Presentation Title |
Deformation Mechanisms in the Medium Entropy Alloy CoCrNi: Effects of Lattice Distortion and Chemical Short-range Order |
Author(s) |
Wu-Rong Jian, Shuozhi Xu, Yanqing Su, Irene J. Beyerlein |
On-Site Speaker (Planned) |
Wu-Rong Jian |
Abstract Scope |
The medium entropy alloy (MEA) CoCrNi has been shown to exhibit an exceptional combination of tensile strength, ductility, and toughness. By using a combination of molecular dynamics, kinetic Monte Carlo, and crystal defect analysis, we investigate the effects of lattice distortion (LD) and chemical short-range order (CSRO) on the nucleation and evolution of dislocations and twins in single crystalline and nanocrystalline CoCrNi under uniaxial tension. For comparison, we repeat calculations on a hypothetical pure A-atom alloy with the same bulk properties of the nominal MEA but no LD or CSRO. We find that LD and CSRO have different effects on nucleation and propagation of Shockley partial dislocations. For instance, LD tends to lower the strain for dislocation nucleation, while higher degrees of CSRO tend to increase it. After yield, twin nucleation is promoted in MEAs, due to the reduced mobility resulting from LD and CSRO. |