材料期刊网

采用力学性能测试、金相分析以及TEM微观结构分析，研究了M152马氏体耐热钢在595℃长期时效过程中的力学性能和结构变化，并探讨了时效脆化机制，结果表明：在595℃时效过程中，发生了显著的回复，位错密度下降，且原始组织中弥散分布的M2C和M7C3碳化物逐渐转变成M23C6型碳化物，并聚集长大，导致强度逐渐降低；时效脆化的主要原因是杂质元素的非平衡晶界偏聚和碳化物的晶界析出共同作用，时效初期的脆化主要是由于M2C型碳化物沿马氏体板条界的连续析出造成的。

The effect of long-term aging below 595℃ on mechanical properties and microstructural evolution ,as well as the mechanism of embrittlement of M152 heat resistant steel are investigated experimentally by means of optical micrograph , TEM and mechanical property tests. The result shows that strength would be reduced gradually during the aging at 595℃ , due to the structural recovery which resulted in the decrease of dislocation density , and the transformation of dispersed M2C and M7C3 carbides within original structure of samples into coarsened M23C6 carbides . The main cause of aging embrittlement was the combination of non-equilibrium segregation to grain boundary of impurities and carbides precipitated in grain boundary , and that was continuous precipitate of M2C carbides along martensitic lathes in the earlier stage of aging.