Dynamics of phase transformations in steel obtained by controlled heating

在这项研究中，显微组织的变化，在逆转过程中的钢进行了检查，重点是（1）的影响，初始结构，（2）非平衡分配的合金元素，（3）在逆转过程中的结晶约束。主要结果如下：Fe-高Ni合金在回复过程中发生位移相变，具有奥氏体记忆。然而，高位错密度在奥氏体相变诱导再结晶，这导致在进一步保持记忆效应消失。在Fe-Mn-C合金中，马氏体相变奥氏体具有粒状和针状两种不同的形貌。这些形态相对于马氏体基体在晶体学特征上是不同的。粒状奥氏体的形成初期处于非平衡状态，在回复后期达到平衡状态。

In this study, microstructure change during reversion of steels was examined focussing on (1) effects of initial structure, (2) non-equilibrium partitioning of alloying elements, and (3) crystallographic constraints during reversion. Main results obtained are as follows.In Fe-high Ni alloys, displacive transformation occurs during reversion with austenite memory. However, a high dislocation density in reversely transformed austenite induces recrystallization which results in disappearance of the memory effect during further holding. In Fe-Mn-C alloys, reversely transformed austenite exhibits two kinds of distinctive morphologies, granular and acicular. Those morphologies are different in crystallographic character with respect to martensite matrix. Also, it was revealed that the granular austenite is formed in non-equilibrium in the beginning and reaches to the equilibrium in the later stage of reversion.