Study of ageing and size effects in Nickel–Titanium shape memory alloy using molecular dynamics simulations

The effect of ageing process at 1073.15 K on the athermal phase transformation in different nanograins (4.5, 6 and 9 nm) Nickel–Titanium shape memory alloy is studied using molecular dynamics simulations. martensitic start temperature transformed martensite volume decrease with decreasing grain size. two-stage intermediate formation observed only smallest (4.5 where a single variant formed. On contrary, larger grains show self-accommodated twinned variants one-stage from austenite to martensite. hardly influences morphology phase, however, it rises reduces temperature. nano size models demonstrate constrained due barrier accumulation internal stress, while shows tendency for stress relaxation.