Tu Xingyang, Ren Yi, Shi Xianbo, Li Changsheng, Yan Wei, Shan Yiyin, Yang Ke
State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China.
State Key Laboratory of Metal Material for Marine Equipment and Application, Anshan 114009, China.
Materials (Basel). 2021 Sep 17;14(18):5358. doi: 10.3390/ma14185358.
In this study the strain capacity and work-hardening behavior of bainite (B), bainite + polygonal ferrite (B + PF), and bainite + polygonal ferrite + pearlite (B + PF + P) microstructures are compared. The work hardening exponent (n), instantaneous work hardening value (n), and differential Crussard-Jaoul (D) analysis were used to analyze the deformation behavior. The best comprehensive mechanical properties were obtained by the introduction of the pearlite phase in B + PF dualphase with the tensile strength of 586 MPa and total elongation of 31.0%. The additional pearlite phase adjusted the strain distribution, which increased the initial work hardening exponent and then maintained the entire plastic deformation at a high level, thus delayed necking. The introduction of pearlite reduced the risk of micro-void initiation combined with the high frequency of high angle grain boundaries (HAGBs) in triple-phase steel, which led to a low crack propagation rate.
在本研究中，对贝氏体（B）、贝氏体+多边形铁素体（B+PF）和贝氏体+多边形铁素体+珠光体（B+PF+P）微观组织的应变能力和加工硬化行为进行了比较。采用加工硬化指数（n）、瞬时加工硬化值（n）和微分Crussard-Jaoul（D）分析来分析变形行为。通过在B+PF双相组织中引入珠光体相获得了最佳综合力学性能，其抗拉强度为586MPa，总伸长率为31.0%。额外的珠光体相调整了应变分布，提高了初始加工硬化指数，然后在高水平上维持整个塑性变形，从而延迟了颈缩。珠光体的引入降低了微孔洞萌生的风险，同时三相钢中高角度晶界（HAGBs）的频率较高，这导致了较低的裂纹扩展速率。
