DFT-supported phase-field study on the effect of mechanically driven fluxes in Ni4Ti3 precipitation
R. Darvishi Kamachali, E. Borukhovich, N. Hatcher, I. Steinbach.
Modelling and Simulation in Materials Science and Engineering, 22, 034003, (2014)
Formation of the Ni4Ti3 precipitate has a strong effect on the shape memory properties of NiTi alloys. In this work, growth of this precipitate is studied using phase-field modelling and density functional theory (DFT) calculations. Using first-principles calculations, the composition-dependent stability and elastic properties of the B2 phase are obtained. Composition-dependent elastic constants are incorporated into our phase-field model to investigate the interplay between stress and concentration fields around the precipitate. The model introduces a source of diffusion due to mechanical relaxation which is accompanied by local softening/hardening of the B2 phase. The results are discussed in light of previous experimental and simulation studies.