纯铁γ—α转变机制求索

Probe into the γ-α Transformation Mechanism of Pure Iron

依据前人的实验数据 ,运用传统计算方法 ,对纯铁γ -α转变扩散机制进行了检验 ,结果表明 :完成转变需用时间的理论计算值与实验值有 3～ 4个数量级的差异。根据非切变相变大多存在非共格相界的特点 ,由相界原子参与相变的设想提出了存在非共格相界的非切变相变“相界与母相原子联动位移”机制。运用热力学基本原理对“联动”和新相连续长大的条件进行了简要分析。对固态相变的分类提出了质疑并建议把“扩散型相变”限定为新相与母相化学成分不同的相变。

Based on available experimental data in literatures, the diffusional mechanism of γ-α transformation is examined by using traditional calculation method. It is shown that the calculated transformation time differs from the experimental data by 3 to 4 orders of magnitude. Assuming that the atoms in interface take part in phase transformation, we proposed a new mechanism of associated translocation of the atoms in incoherent interface and the parent phase for non shear transformation. The associated translocation proccedure and the condition for the continuous growth of new phase is briefly analyzed by using principals of thermodynamics. It is suggested that the diffusional phase transformation should be confined to the transformation that result in chemical composition change between new phase and parent phase.