| In order to discuss on the mechanism of massive transformation, the effect of the cooling rate on massive transformation start temperature, massive transformation peak temperature and massive transformation finish temperature, and the free energy change accompanied with massive transformation of Fe-Ni binary alloy, have been studied by means of Differential Thermal Analysis (DTA). The results obtained are as follows. 1) The λtype heat evolution attributed to massive transformation, has been observed in the DTA curve. Also, the serration of heat evolution has been observed in the DTA curie scanned below a certain cooling rate. It has been found that the mechanism of massive transformation has been explained by the occurance of serration in the heat evolution. 2) Massive transformation start temperature has been constant, independent on the cooling rate. However, massive transformation peak temperature and massive transformation finish temperature have decreased with the cooling rate, and its behavior has distinguished into the three region. 3) Massive transformation start temperature has decreased with Ni content in Fe-Ni binary alloy, however the free energy change accompanied with massive transformation has increased with Ni content in it. 4) Massive transformation has not occurred but maitensite transformation has occurred at a cooling rate below 2.5×10^(-1)˚K/s. |
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