| The effects of thermal cycling treatment on mechanical properties and transformation temperatures of Fe-20%Mn alloy were studied. With increasing number of the thermal cycling between room temperature and 260℃, the amount of ε martensite sharply increased up to 3 cycles and showed parabolic increase beyond 3 cycles, but the amount of γ austenite showed exactly the reverse. When the alloy was deformed to fracture at room temperature, the amount of ε martensite decreased but α′ martensite increased gradually with thermal cycling. On the other hand, γ could not be found except ε and α′ martensites in the fractured samples. As the number of thermal cycling increased, the hardness, UTS and YS of the alloy increased, the ε martensite plate became finer, a large number of dislocations were introduced in γ parent phase, and M_s was lowered. |
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