595℃长期时效对M152马氏体耐热钢力学性能的影响

来源期刊：钢铁2010年第7期

论文作者：杨钢 郭永华 刘新权 马风春 宋玺玉 张秀丽

文章页码：66 - 70

关键词：M152马氏体耐热钢； 力学性能； 时效； 脆化机制

Key words：M152 martensitic heat resistant steel； mechanical property； aging； mechanism of embrittlement

摘    要：采用力学性能测试、金相分析及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碳化物沿马氏体板条界的连续析出造成的。

Abstract: 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 were 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 is the combination of non-equilibrium segregation to grain boundary of impurities and carbides precipitates in grain boundary,and that is continuous precipitate of M₂C carbides along martensitic lathes in the earlier stage of aging.