Allotropic phase transformations may be driven by the application of stress – this is especially well-known for pressure-driven transformations. Recent advances in strengthening materials allow for the application of very large shear stresses as well - opening up vast new regions of stress space. The presence of shear implies that phase transformations depend upon the full stress tensor and crystal/grain orientation. We propose a crystal thermodynamics framework for describing phase transformations in polycrystalline solids and apply it through non-linear elasticity and density functional theory calculations. In particular, we consider bcc➜hcp transformations in iron, fcc➜hcp transformations in nickel, and hcp➜fcc transformations in titanium. The results are quantitatively consistent with a range of experimental observations in these disparate systems.
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Meeting ID: 933 5117 9800 Passcode: TYCIGS
Join Zoom Meeting:
https://ucl.zoom.us/j/93351179800?pwd=bVBhNjJhZURNc05wR1piTUtTWXBVUT09
Meeting ID: 933 5117 9800 Passcode: TYCIGS
