Modeling of pseudoelasticity via reversible slip in Fe_3Ga

摘要

The Fe_3Ga alloy with the cubic D0_3 lattice possesses considerable recoverable strain due to the slip reversibility. Pseudoelasticity via reversible slip in Fe_3Ga is studied with atomistic simulations. An extended Peierls–Nabarro model incorporating the Generalized Stacking Fault Energy (GSFE) is established to determine Peierls stress in D0_3 and L1_2 Fe_3Ga. The back stress and frictional stress are predicted during loading and unloading process. These stress magnitudes govern the reversible slip in Fe_3Ga. The results show that the reversible slip observed experimentally in D0_3 Fe_3Ga is induced by its larger back stress compared to its frictional stress. In contrast, the reversible slip cannot appear in L1_2 since its back stress is not large enough to pull back superpartials, and thus the existence of L1_2 will suppress the pseudoelasticity of D0_3 Fe_3Ga and results in decreasing the strain recovery. The present study has explored the theoretical foundations of this phenomenon arising from high back stresses responsible for cyclic reversible dislocation motion.