晶内铁素体的形核机理

Nucleation Mechanisms of Intragranular Ferrite (IGF)

系统地研究了MnS、CuS及其复合物附近的微区在晶内铁素体形核过程中的成分变化,未发现诱导晶内铁素体形核的MnS、CuS及其复合物附近的微区锰含量有明显的变化。夹杂物诱导晶内铁素体形核的机理是:夹杂物作为一种惰性介质具有较高的惰性界面能,它对诱导晶内铁素体形核起主要作用。夹杂物造成其附近有较高的应力 应变能,夹杂物与铁素体的错配度较小均促进晶内铁素体的形核、长大。

The chemical composition in the micro-zone adjacent to MnS, CuS and its compounds as inductors for IGF was analyzed, the change is Mn in the micro-zone adjacent to MnS, CuS and its compound has not been observed. The mechanisms in which the inclusions induct intragranular ferrite formation include three factors. As an inert nucleation site, the inclusion can reduce the nucleation energy remarkably, which is the most important factor. Besides the inclusions have different thermal expansion coefficients from that of the substrate metal, thus a high stress-stain field around the inclusions is observed, and there is small lattice mismatch between inclusions and ferrite. These last two factors are beneficial to the nucleation and growth of intragranular ferrite.