Xu Sheng, Xu Haijie, Shu Xuedao, Li Shuxin, Shen Zhongliang
College of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211, China.
Department of Mechanical Engineering, Zhejiang Business and Technology Institute, Ningbo 315012, China.
Materials (Basel). 2022 Apr 6;15(7):2702. doi: 10.3390/ma15072702.
Warm compression tests were carried out on low carbon and low alloy steel at temperatures of 600−850 °C and stain rates of 0.01−10 s−1. The evolution of microstructure and texture was studied using a scanning electron microscope and electron backscattered diffraction. The results indicated that cementite spheroidization occurred and greatly reduced at 750 °C due to a phase transformation. Dynamic recrystallization led to a transition from {112}<110> texture to {111}<112> texture. Below 800 °C, the intensity and variation of texture with deformation temperature is more significant than that above 800 °C. The contents of the {111}<110> texture and {111}<112> texture were equivalent above 800 °C, resulting in the better uniformity of γ-fiber texture. Nucleation of <110>//ND-oriented grains increased, leading to the strengthening of <110>//ND texture. Microstructure analysis revealed that the uniform and refined grains can be obtained after deformation at 800 °C and 850 °C. The texture variation reflected the fact that 800 °C was the critical value for temperature sensitivity of warm deformation. At a large strain rate, the lowest dislocation density appeared after deformation at 800 °C. Therefore, 800 °C is a suitable temperature for the warm forming application, where the investigated material is easy to deform and evolves into a uniform and refined microstructure.
在600−850 °C的温度和0.01−10 s−1的应变速率下，对低碳钢和低合金钢进行了热压缩试验。使用扫描电子显微镜和电子背散射衍射研究了微观结构和织构的演变。结果表明，由于相变，渗碳体球化在750 °C时发生且大大减少。动态再结晶导致织构从{112}<110>转变为{111}<112>。在800 °C以下，织构强度和随变形温度的变化比在800 °C以上时更为显著。在800 °C以上，{111}<110>织构和{111}<112>织构的含量相当，导致γ纤维织构具有更好的均匀性。<110>//ND取向晶粒的形核增加，导致<110>//ND织构增强。微观结构分析表明，在800 °C和850 °C变形后可获得均匀且细化的晶粒。织构变化反映出800 °C是热变形温度敏感性的临界值。在大应变速率下，800 °C变形后位错密度最低。因此，800 °C是热成形应用的合适温度，在此温度下所研究的材料易于变形并演变成均匀且细化的微观结构。
