Thermal ageing on the deformation and fracture mechanisms of a duplex stainless steel by quasi in-situ tensile test under OM and SEM

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• 作者：Y. Wang ; Y.H. Yao ; ^{yyhong0612@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; ^{yyhong0612@xatu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Z.P. Wang ; Y.H. Jin ; X.L. Zhang ; J.N. Liu
• 关键词：Z3CN20-09M CDSSs ; Quasi in-situ tensile test ; Thermal ageing ; Gliding steps ; Phase boundary
• 刊名：Materials Science & Engineering A
• 出版年：2016
• 出版时间：1 June 2016
• 年：2016
• 卷：666
• 期：Complete
• 页码：184-190
• 全文大小：8915 K

文摘

To clarify the effects of the long-term thermal ageing embrittleness on the deformation and fracture mechanism of casting duplex stainless steels (CDSSs), quasi in-situ tensile tests under OM and SEM are conducted for Z3CN20-09M CDSSs thermally aged up to 10,000 h. Regardless of thermal ageing, the single sliding, multi-gliding and cross-slipping are the main deformation mechanisms in the austenite and ferrite under tensile load. The long-term thermal ageing mainly affects the initiation and the propagation of the cracks and then influences the fracture mechanisms. For the as-received specimen, the cracks initiate in the locations of the impurity particles both within the austenite and ferrite grains and between the δ/γ phase boundaries. For the spinodal decomposition, the precipitation of the G-phase and the coarsening of the spinodally decomposed structure in ferrite, the cracks mainly originate in the δ/γ phase boundary and the slip steps in ferrite. The fracture mode changes from the microvoid coalescence ductile fracture of the as-received specimen, to the quasi-cleavage fracture in ageing time of 3000 h and to the cleavage fracture in ferrite and the quasi-cleavage fracture in austenite in ageing time of 10,000 h.