高锰无磁钢ZG25Mn18Cr4的加工硬化机理

在应力作用下快速加工硬化是高锰无磁钢ZG25Mn18Cr4的一个重要特征．通过X衍射和电子显微分析证明，变形前和变形后的基体组织都是奥氏体基体加上碳化物，变形前后的基体中均存在条纹状组织，且变形后基体中的条纹数量明显高于变形前基体中的条纹数量．电子衍射分析表明这些出现在粗大奥氏体晶粒内部的条纹组织是高密度层错．由塑性变形产生的大量层错分割了奥氏体基体，缩短了位错运动的自由程，导致了ZG25Mn18Cr4的迅速加工硬化．

Work-hardening Mechanism of Non-magnetic High Manganese ZG25Mn18Cr4 Castings

The important character of non-magnetic high manganese ZG25 Mn18Cr4 alloy is rapid work-hardening under external stress. With X-ray diffraction and TEM analysis, it is proved that the microstructures of both undeformed and deformed matrixes are austenite and carbide with some striation structure in the matrixes, the amount of stripes in the deformed matrix is obviously more than that in the undeformed matrix. Electronic diffraction analysis confirmed that the stripes in coarse austenite grains are high density lamination fault sheets. A great deal of lamination fault sheets produced by plastic deformation divides up austenite matrix, shortens the free distance of dislocation movement and results in the rapid work-hardening of ZG25Mn18Cr4 alloy.