Factors affecting transformation temperatures in Fe-Mn-Si-Cr-Ni shape memory alloy

The effects of prestrain and annealing temperature on phase transformation temperatures in Fel4Mn5Si8Cr4Ni shape memory alloy have been studied. The r esults showed that when the annealing temperature was 673 K, both the A(f) and the M-s temperatures increased appreciably as the prestrain increased, the A, temperature increased slightly with increasing prestrain; the resist ivity difference at 303 K between the heating and cooling curve also increa sed with increasing prestrain, which agreed with the recovery strain. The s hape memory effect in Fe-Mn-Si-Cr-Ni shape memory alloy is caused by the st ress-induced gamma --> epsilon martensite transformation and its reverse tr ansformation. When the prestrain was 10%, the M-s temperature decreased rem arkably as the annealing temperature increased.