Discontinuous lath martensite transformation and its relationship with annealing twin of parent austenite and cooling rate in low carbon RAFM steel
Discontinuous lath martensite transformation and its relationship with annealing twin of parent austenite and cooling rate in low carbon RAFM steel
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DOI：
10.1016/j.matdes.2020.109252
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发表时间：
2021
影响因子：
8.4
通讯作者：
C. Mao;Chenxi Liu;Liming Yu;Huijun Li;Yong-chang Liu
中科院分区：
文献类型：
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作者：
C. Mao;Chenxi Liu;Liming Yu;Huijun Li;Yong-chang Liu
低碳钢中的板条马氏体相变与相变速率的不连续性有关，表现为一系列的马氏体相变速率极大值(峰)，特别是在低冷却速率下。本文着重研究了低碳还原活化铁素体/马氏体钢(RAFM)中母晶奥氏体(PAG)中的退火孪晶(PAG)和冷却速度对板条马氏体相变速率间断的影响。冷却过程中板条马氏体组织呈层次化，板条马氏体相变速率峰呈层次化。如果冷却速度不够高，板条马氏体相变速率峰会因母奥氏体中的孪晶而分成两组。第一组相变速率峰主要由PAGS中非孪晶区的板条马氏体相变引起。第二组主要由一个转变速率峰组成，该峰主要由PAGS中孪晶区的马氏体相变引起。本文提出了一种新的“局域应力场”理论，并成功地用来解释板条马氏体相变速率峰的分类机制以及这些峰随冷却速度的变化规律。
Lath martensite transformation in low carbon steel relates to the discontinuity of the transformation rate, which exhibits a series of martensite transformation rate maxima (peaks), especially in low cooling rates. In the present work, we put an emphasis on the influence of annealing twins in parent austenite grains (PAGs) and cooling rates on the discontinuity of lath martensite transformation rate in a low carbon reduced activation ferritic/martensitic (RAFM) steel. Lath martensite microstructure is hierarchical and the lath martensite transformation rate peaks are hierarchical during the cooling process. If the cooling rate was not high enough, the lath martensite transformation rate peaks will be divided into two groups by annealing twins in parent austenite. These transformation rate peaks in the first group were mainly caused by lath martensite transformation in the non–twin zones in the PAGs. Then, the second group mainly consisted of a single transformation rate peak, which was primarily caused by the martensite transformation in the twin zones in the PAGs. In the present work, a new “localized stress field” theory is proposed and successfully used for interpreting the classification mechanism of lath martensite transformation rate peaks and the evolution of these peaks with changing cooling rate.