DSC study of the effect of aging temperature on the reverse martensitic transformation in porous Ni-rich NiTi shape memory alloy fabricated by combustion synthesis

摘要

The effect of aging temperature on the reverse martensitic transformation in the SHS-synthesized porous Ni-rich NiTi SMA after solution treated at 1050 deg C for 4 h is investigated using differential scanning calorimeter (DSC) and discussed. The type of reverse martensitic transformation changes from one step B19'- >B2 (after solution treated) through two steps B19'- >R- >B2 (after aged at 400, 450 and 475 deg C) back to one step B19'- >B2 (after aged at 500 deg C). Both the austenite finish temperature (A_f) and the peak temperature corresponding to the transformation of R- >B2 decrease with the rise of the aging temperature. The experimental results also indicate that shape memory properties of porous NiTi SMA fabricated by SHS can be improved by optimizing the aging technology.