超高强度马氏体时效不锈钢中逆转变奥氏体的析出与长大行为

研究了一种Cr-Ni-Co-Mo系超高强度马氏体时效不锈钢中逆转变奥氏体的析出与长大行为。结果表明,经540℃×4 h时效后钢的强度达到峰值1940 MPa,并有薄膜状逆转变奥氏体沿马氏体板条界上非连续析出,使钢具有良好的综合力学性能。时效初期逆转变奥氏体在马氏体板条、板条界或原奥氏体晶界处形核,随着保温时间的延长,薄膜状的逆转变奥氏体通过与扩散有关的形核长大方式生长,最终形成块状,并与板条马氏体间保持着K-S或N-W关系。

Growth behavior and precipitation of reverted austenite in ultra-high strength marageing stainless steel

The growth behavior and precipitation of reverted austenite in Cr-Ni-Co-Mo marageing stainless steel were investigated.The results show that the strength of the steel aged at 540 ℃ for 4 h reaches up to 1940 MPa,and the thin-film shape reverted austenite precipitates at the boundaries of lath martensite,so that a good combination of strength and toughness of the steel is obtained.In early aging stage,the reverted austenite precipitates firstly at lath martensite,the boundaries of lath martensite or prior austenitic grain boundary,with prolonging aging time,the thin-film reverted austenite grows up into blocky austenite by atomic diffusion,the orientation relationship between the reverted austenite and martensite is K-S or N-W.