The effect of plastic deformation on the martensite-to-austenite transition in an iron-nickel alloy

The effect of plastic deformation introduced by rolling at room temperature on the austenite start temperature of an Fe-30.3 wt pct Ni-0.005 wt pct C alloy has been determined. The austenite start temperature increases monotonically with deformation. Microhardness measurements show that the austenite start temperature increases with the yield strength of the martensite. The temperature at which martensite reversal initiates is not affected by the amount of martensite present, and, therefore, is not dependent on the martensite plate size. It is suggested that the reverse martensite transformation initiates at the martensite-austenite interface and is controlled by interface propagation.