细晶T2纯铜动态力学性能及本构模型

2019-11-15

作者：吴尚霖1，鞠康1，段春争1，孔金星2 单位：1大连理工大学机械工程学院；2中国工程物理研究院机械制造工艺研究所

摘要：晶粒大小是影响多晶金属材料力学性能的重要因素之一，研究细晶T2纯铜在高温、高应变率下的动态力学性能并建立其本构模型对切削加工有着重要意义。通过电子力能测试仪进行T2纯铜试样准静态压缩试验，并利用霍普金森压杆装置完成了不同应变率和不同温度的动态压缩试验。试验结果表明，纯铜材料具有明显的应变强化效应和温度软化效应，其动态压缩下的强度高于准静态压缩，但在高应变率区域内，并无明显的应变率强化效应。基于JohnsonCook本构模型得到了细晶T2纯铜本构方程参数，拟合曲线与试验结果吻合较好。

关键词：T2纯铜；高应变率；应力—应变曲线；JohnsonCook本构模型

中图分类号：TG61；TH161.3文献标志码：ADOI：10.3969/j.issn.1000-7008.2019.11.004

Dynamic Mechanical Properties and Constitutive Model of Finegrained T2 Copper

Wu Shanglin，Ju Kang，Duan Chunzheng，Kong Jinxing

Abstract:Grain size is one of the important factors affecting the mechanical properties of polycrystalline metal materials.Studying the dynamic mechanical properties of finegrained T2 copper at high temperature and high strain rate and establishing its constitutive model have important significance for cutting process.In this paper，the quasistatic compression tests of the T2 copper sample are carried out by electronic force tester，and dynamic compression tests at different strain rates and different temperatures are performed by Hopkinson pressure bar device.The results show that the pure copper material has obvious strain strengthening effect and temperature softening effect.Its strength under dynamic compression is higher than that under quasistatic compression.However，there is no obvious strain rate strengthening effect in the high strain rate region.The parameters of the constitutive equation of the finegrained T2 pure copper are obtained based on the JohnsonCook constitutive model.The fitting curves agree well with the experimental results.

Keywords:T2 copper；high strain rate；stressstrain curve；JohnsonCook constitutive model