摘要
以无间隙原子钢H260YD+Z为研究对象,分析了应变速率对其力学性能和断口形貌的影响。首先,获取了7种应变速率下H260YD+Z钢的高速拉伸力学性能曲线,并分析了关键参数的变化规律;然后,基于Johnson-Cook模型建立了材料的动态力学性能本构模型,并采用穿孔试验与仿真对比分析,验证了所搭建的本构模型的准确性;最后,分析了不同应变速率下拉伸试样的断口形貌,获取了韧窝和裂纹的分布规律。结果表明:HC260YD+Z钢呈现明显的应变速率敏感性,强度与应变速率呈正相关,塑性特征的变化趋势则相对复杂;不同应变速率下的拉伸断口均呈韧窝状,为韧性断裂特征,且韧窝的尺寸和密度随着应变速率的提升而增大;断裂裂纹最先萌生于铁素体的晶界,且越靠近断口,裂纹的密度越大;Johnson-Cook本构模型的拟合曲线的决定系数大于0.97,且穿孔试验与仿真分析获取的关键参数偏差低于5%,表明所搭建的材料本构模型的表征精度较高。
For H260YD+Z interstitial free steel,the influences of strain rate on mechanical properties and fracture morphology were ana-lyzed.Firstly,the high-speed tensile mechanical property curves of H260YD+Z steel at seven strain rates were obtained,and the variation rules of key parameters were analyzed.Then,based on the Johnson-Cook model,the dynamic mechanical property constitutive model of the material was established,and the accuracy of the constructed constitutive model was verified by the comparison analysis between the perforation test and the simulation.Finally,the fracture morphology of tensile specimens under different strain rates was analyzed,and the distribution laws of dimples and cracks were obtained.The results show that HC260YD+Z steel exhibits obvious strain rate sensitivity,the strength is positively correlated with the strain rate,and the change trend of plastic characteristics is relatively complex.The tensile frac-tures under different strain rates are all dimple-shaped,which are ductile fracture characteristics,and the size and density of the dimples increase with the increasing of strain rate.The fracture crack first initiates at the grain boundary of ferrite,and the closer to the fracture,the greater the crack density.The determination coefficient of the fitting curve for the Johnson-Cook constitutive model exceeds 0.97,and the deviation of the key parameters obtained by the perforation test and the simulation analysis is less than 5%,indicating that the con-structed material constitutive model has high characterization accuracy.
作者
王彦婷
张龙列
黑中垒
Wang Yanting;Zhang Longlie;Hei Zhonglei(College of Automotive Engineering,Huanghe Jiaotong University,Jiaozuo 454950,China;Do-Fluoride New Materials Co.,Ltd.,Jiaozuo 454950,China)
出处
《锻压技术》
北大核心
2025年第6期249-258,共10页
Forging & Stamping Technology
基金
河南省教育科学规划2024年度一般课题(2024YB0398)。
关键词
应变速率
力学性能
韧性断裂
断口形貌
穿孔
strain rate
mechanical properties
ductile fracture
fracture morphology
perforation
