The response of accumulated stress and microstructural refinement on cyclic deformation and associated mechanism in high strength bainite-martenite dual-phase steel
The response of accumulated stress and microstructural refinement on cyclic deformation and associated mechanism in high strength bainite-martenite dual-phase steel
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DOI：
10.1016/j.msea.2018.10.003
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
P. Zhao;F. Du;E. Yan;R. Misra;Zhong-li Liu
中科院分区：
文献类型：
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作者：
P. Zhao;F. Du;E. Yan;R. Misra;Zhong-li Liu
阐述了累积应力和组织细化对高强度贝氏体-马氏体双相钢超高循环变形的响应及相应的裂纹萌生机制，其中非夹杂物诱发裂纹萌生是主要的失效模式。非夹杂物诱发的裂纹萌生包括当外加应力累积时，粗大贝氏体板条中的微孔洞形核。微孔洞的密度随着外加应力的积累而增加，靠近晶界的微孔洞连接在一起形成微裂纹。当微裂纹结合在一起形成宏观裂纹时，就会发生破坏。裂纹扩展的前提是裂纹尖端的总应力强度因子大于颗粒亮面(GBF)裂纹扩展门槛值。提出了非夹杂诱发裂纹的数学判据。研究表明，细化贝氏体板条组织可以降低裂纹萌生的概率。
We elucidate here the response of accumulated stress and microstructural refinement on the ultra-high cyclic deformation and associated crack initiation mechanism in high strength bainite-martenite dual-phase steel, where non-inclusion induced crack initiation is the dominated failure mode. The non-inclusion induced crack initiation involved nucleation of microvoids in the coarse bainitic lath when the applied stress accumulated. The density of the microvoids increased with the accumulation of applied stress, and the microvoids that were near the grain boundary connected to form a microcrack. Failure occurred when the microcracks combined to form a macrocrack. The premise of crack propagation is that the total stress intensity factor at the crack tip is larger than granular bright facet (GBF) crack growth threshold value. A mathematical criterion is proposed for non-inclusion induced cracking. The study suggested that the probability of crack initiation is reduced when the microstructural constituent, bainitic lath, is refined.