摘要
对400℃下热老化长达20000 h的Z3CN20-09M的组织转变进行了透射电镜观察。对不同时间热老化后Z3CN20-09M的裂纹扩展性能进行了研究,并讨论了热老化时间对裂纹扩展速率的影响。用扫描电镜对裂纹扩展面进行分析,研究了裂纹扩展机制。透射电镜实验结果表明:热老化后铁素体中富Cr的α'相随热老化时间延长数量不断增多。疲劳裂纹扩展速率可用Paris公式拟合,裂纹扩展速率随热老化时间延长而增快。拟合的Paris公式指数n随热老化时间延长而增加,lnC随热老化时间延长而减小,而且指数n与lnC呈线性关系。扫描电镜结果表明,裂纹扩展速率的增快与热老化后铁素体的解理断裂有关。
Microstructure evolution of ferrite phase in Z3CN20-09M, thermally aged at 400 ℃ for up to 20000 h, was investigated by TEM. The fatigue crack growth properties of thermally aged materials were studied and the influence of thermal aging time was discussed. Fracture surface analysis by SEM was performed to investigate the crack propagation micro mechanisms. TEM results show that Cr-enriched α＇ phases are precipitated in ferrite phase and increase with the increase of aging time. Fatigue crack growth rates are fitted by Paris law, and the fitted crack growth rates increase with the increase of aging time. The fitted parameter exponent n increases, while lnC decreases with the increase of thermal aging time, and exponent n is linearly fitted against InC. The increase in crack growth rate is associated with brittle cleavage of the ferrite phase.
出处
《热加工工艺》
CSCD
北大核心
2013年第18期134-137,共4页
Hot Working Technology
基金
国家863计划资助项目(2012AA03A507
2012AA050901)
国家重大专项(2011ZX06004)
关键词
核电主管道
不锈钢
热老化
疲劳裂纹扩展
nuclear primary pipe
stainless steel
thermal aging
fatigue crack growth
