Effect of thermal aging on the fatigue crack growth behavior of cast duplex stainless steels
来源期刊：International Journal of Minerals Metallurgy and Materials2015年第11期
论文作者：Xu-ming Lü Shi-lei Li Hai-long Zhang Yan-li Wang Xi-tao Wang
文章页码：1163 - 1170
摘 要：The effect of thermal aging on the fatigue crack growth（FCG） behavior of Z3CN20?09M cast duplex stainless steel with low ferrite content was investigated in this study. The crack surfaces and crack growth paths were analyzed to clarify the FCG mechanisms. The microstructure and micromechanical properties before and after thermal aging were also studied. Spinodal decomposition in the aged ferrite phase led to an increase in the hardness and a decrease in the plastic deformation capacity, whereas the hardness and plastic deformation capacity of the austenite phase were almost unchanged after thermal aging. The aged material exhibited a better FCG resistance than the unaged material in the near-threshold regime because of the increased roughness-induced crack closure associated with the tortuous crack path and rougher fracture surface; however, the tendency was reversed in the Paris regime because of the cleavage fracture in the aged ferrite phases.
Xu-ming Lü1，Shi-lei Li1，Hai-long Zhang1，Yan-li Wang1，Xi-tao Wang1,2
1. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing2. Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing
摘 要：The effect of thermal aging on the fatigue crack growth（FCG） behavior of Z3CN20?09M cast duplex stainless steel with low ferrite content was investigated in this study. The crack surfaces and crack growth paths were analyzed to clarify the FCG mechanisms. The microstructure and micromechanical properties before and after thermal aging were also studied. Spinodal decomposition in the aged ferrite phase led to an increase in the hardness and a decrease in the plastic deformation capacity, whereas the hardness and plastic deformation capacity of the austenite phase were almost unchanged after thermal aging. The aged material exhibited a better FCG resistance than the unaged material in the near-threshold regime because of the increased roughness-induced crack closure associated with the tortuous crack path and rougher fracture surface; however, the tendency was reversed in the Paris regime because of the cleavage fracture in the aged ferrite phases.
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