材料期刊网

纯铁γ-Fe的α-Fe转变遵循过渡相界铁原子个体有序位移机制,这个机制本质上等同于切变而差异于扩散机制。凡是过冷含碳奥氏体的先共析铁素体析出,必然服从相界铁原子个体有序位移机制;这是固态相变第一法则;凡是无碳铁素体必然得自过冷无碳奥氏体,故过冷含碳奥氏体务必预先除碳,这是第二法则。珠光体分解实质上为过冷无碳奥氏体的珠光体铁素体层片的析出,等轴铁素体的析出亦然。在此不存在铁原子个体无序位移扩散机制。铁碳系统固态相变存在群体有序位移切变与过渡相界个体有序机制两类型机制,切变和扩散两类型的分类不具现实和理论意义,这是固态相变物理的科学发展。

The γ-Fe→α-Fe transformation of pure iron obeys the mechanism of iron atom individuals displacement of the transitional phase boundary, this mechanism is essentially equivalent to classical shear and different from diffusional mechanism. All the precipitation of proeutectoid ferrite certainly obeys the individual ordered displacement mechanism of iron atom at the transitional phase boundary, it is the first rule of solid transformation. Prior exclusion of carbon content of overcooling austenite is prerequisite for phase transformation of the overcooling non-carbon austenite to non-carbon ferrite, it is the second rule of solid transformation. The pealitic decomposition essentially is the pealitic ferrite precipitation of overcooling non-carbon austenite. It is argued that the diffusional mechanism of iron atom individual disordered displacement is not existence, and in fact the solid these transformations occurs by the mechanism of ordered displacement of multiple iron atoms or individual iron atom. The classification of shear and diffusinnal mechanism in solid transformation is meaningless.