Chen Xuewen, Guo Lele, Zhang Bo, Bai Rongren
School of Materials Science and Engineering, Henan University of Science and Technology, 263 Kaiyuan Avenue, Luoyang 471023, China.
Materials (Basel). 2022 May 31;15(11):3935. doi: 10.3390/ma15113935.
To effectively control and predict crack defects in the high-temperature forming process of Cr5 alloy steel, based on the traditional Lemaitre damage model, a new high-temperature damage model of Cr5 alloy steel was proposed which considered the change of material elastic modulus with temperature, the influence of material hydrostatic pressure as well as temperature and strain rate on material damage. Because Cr5 alloy steels are usually forged at high temperatures, tensile testing is an important method to study the damage behaviour of materials. Through the high-temperature tensile test and elastic modulus measurement test of the Cr5 alloy steel, the stress-strain curves and the relationship curves of the elastic modulus value with the temperature of Cr5 alloy steel under different temperatures and strain rates were obtained. A new high-temperature damage model of Cr5 alloy steel was built by introducing the Zener-Hollomon coefficient considering the influence of temperature and strain rate. The established high-temperature damage model was embedded in Forge finite element software through the program's secondary development method to numerically simulate the experimental process of Cr5 alloy steel. Comparing the difference between the displacement-load curves of the numerical simulation and the actual test of the tensile process of the experimental samples, the correlation coefficient R is 0.987 and the difference between the experimental value and the simulated value of the tensile sample elongation at break is 1.28%. The accuracy of the high-temperature damage model of Cr5 alloy steel established in this paper was verified. Finally, the high-temperature damage map of Cr5 alloy steel was constructed to analyse the variation law of various damage parameters with the temperature and strain rate of the high-temperature damage model of Cr5 alloy steel.
为有效控制和预测Cr5合金钢高温成形过程中的裂纹缺陷，基于传统的勒梅特损伤模型，提出了一种新的Cr5合金钢高温损伤模型，该模型考虑了材料弹性模量随温度的变化、材料静水压力以及温度和应变速率对材料损伤的影响。由于Cr5合金钢通常在高温下锻造，拉伸试验是研究材料损伤行为的重要方法。通过对Cr5合金钢进行高温拉伸试验和弹性模量测量试验，得到了不同温度和应变速率下Cr5合金钢的应力-应变曲线以及弹性模量值与温度的关系曲线。考虑温度和应变速率的影响，引入齐纳-霍洛蒙系数，建立了Cr5合金钢的高温损伤模型。通过程序二次开发方法将所建立的高温损伤模型嵌入到Forge有限元软件中，对Cr5合金钢的试验过程进行数值模拟。对比数值模拟与试验样品拉伸过程实际测试的位移-载荷曲线差异，相关系数R为0.987，拉伸样品断裂伸长率试验值与模拟值的差值为1.28%。验证了本文建立的Cr5合金钢高温损伤模型的准确性。最后，构建了Cr5合金钢高温损伤图，分析了Cr5合金钢高温损伤模型各损伤参数随温度和应变速率的变化规律。
