Correlation between strength and hardness for substructures of lath martensite in low- and medium-carbon steels
Correlation between strength and hardness for substructures of lath martensite in low- and medium-carbon steels
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DOI：
10.1016/j.msea.2022.144007
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
Kwangsik Kwak;Y. Mine;S. Morito;T. Ohmura;K. Takashima
中科院分区：
文献类型：
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作者：
Kwangsik Kwak;Y. Mine;S. Morito;T. Ohmura;K. Takashima
在这项研究中，系统地进行了微拉伸和纳米压痕试验，以评估块状边界对屈服强度的贡献，并将淬火板条马氏体钢的强度和硬度与低碳和中碳含量相关联。在单块（SB）和单包（SP）结构中观察到与习惯面相关的屈服行为，与碳含量无关。低角度边界难以有效地对位错运动起到阻碍作用。这表明，各向异性屈服行为可归因于变形早期形成的位错壁结构。据估计，随着标称碳含量的增加，屈服开始时单块边界对分解剪切应力的贡献是恒定的。这表明板条马氏体组织的屈服强度通过块状细化和固溶强化随着碳含量的增加而增加。建立了SP和SB组织的抗拉强度与硬度之间的关系。包含块体边界强度的相关系数符合Tabor关系，而不包含块体边界强度的矩阵对应的系数几乎比Tabor常数低一半。
In this study, microtensile and nanoindentation tests were systematically performed to evaluate the contribution of the block boundary to yield strength and to correlate the strength and hardness of as-quenched lath martensite steels with low- and medium-carbon contents. A habit-plane-dependent yielding behaviour was observed in the single-block (SB) as well as single-packet (SP) structures, independent of the carbon content. The low-angle boundary is difficult to effectively act as an obstacle for dislocation motion. This suggests that the anisotropic yielding behaviour can be attributed to the dislocation wall structures formed during the early stage of deformation. The contribution of the single-block boundary to the resolved shear stress at the onset of yielding was estimated to be constant with increasing nominal carbon content. This indicates that the yield strength of the lath martensite structure increases with increasing carbon content through block refinement and solid solution strengthening. The relationship between tensile strength and the corresponding hardness was established for the SP and SB structures. The correlation coefficient, including the block boundary strength, was in accordance with the Tabor relationship, whereas the coefficient corresponding to the matrix excluding the block boundary strength was almost half lower than the Tabor's constant.