Cao Jingyi, Jin Jianfeng, Li Shaojie, Wang Mingtao, Tang Shuai, Peng Qing, Zong Yaping
School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China.
State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China.
Materials (Basel). 2022 Jan 26;15(3):952. doi: 10.3390/ma15030952.
The effect of microstructure on the onset strain and rate of deformation-induced martensitic transformation (DIMT) in Q&P steel is studied by a mean-field micromechanics model, in which the residual austenite () and primary martensite () phases are treated as elastoplastic particles embedded into the ferrite () matrix. The results show that when the volume fraction of the increases with a constant fraction of the , the onset strain of DIMT increases and transformation rate decreases, in contrast to the case of the fraction effect with a fixed fraction. Increasing the volume fraction of the postpones the DIMT, regardless of the corresponding change from the or fraction, which is similar to the effect of the fraction with the constant but to a higher degree. Conversely, when increasing the fraction of the matrix , the onset strain of DIMT increases and the rate decreases, and the effect is greater when the corresponding fraction change comes from the rather than from the . Moreover, when the aspect ratio of the increases, the onset strain of DIMT decreases with a gradual increase in transformation rate, in agreement with the experimental observation that the equiaxial austenite is more stable in Q&P steels. However, the aspect ratio effect of the is opposite to that of the , indicating that the lath-shaped primary martensite could protect the austenite from DIMT.
通过平均场微观力学模型研究了组织对Q&P钢中变形诱发马氏体相变（DIMT）的起始应变和速率的影响，其中残余奥氏体（ ）和初生马氏体（ ）相被视为嵌入铁素体（ ）基体中的弹塑性颗粒。结果表明，当 的体积分数在 的分数恒定时增加时，DIMT的起始应变增加而转变速率降低，这与 分数固定时 分数效应的情况相反。增加 的体积分数会推迟DIMT，无论 或 分数的相应变化如何，这与 分数恒定但程度更高时 分数的效应相似。相反，当增加基体 的分数时，DIMT的起始应变增加而速率降低，并且当相应的分数变化来自 而非 时，效果更大。此外，当 的长径比增加时，DIMT的起始应变降低，转变速率逐渐增加，这与实验观察结果一致，即在Q&P钢中，等轴奥氏体更稳定。然而， 的长径比效应与 的相反，表明板条状初生马氏体可以保护奥氏体不发生DIMT。
