宽应变率范围下2A16-T4铝合金动态力学性能

为了研究2A16-T4铝合金的动态力学性能，利用电子万能试验机、高速液压伺服试验机及霍普金森压杆(SHPB)装置进行常温下准静态、中应变率和高应变率的动态力学性能实验，得到不同应变率下的应力应变曲线，基于修正的Johnson-Cook本构模型对它进行拟合，并分析材料中应变率力学特性对模型应变率敏感参量的影响。结果表明:2A16-T4铝合金在应变率10-4~102 s-1范围内应变率敏感性较弱，而在102~103 s-1范围内应变率敏感性较强，且应变率强化效应随塑性应变的增大而减小；同时，在10-4~103 s-1范围内具有较强的应变硬化效应，且应变硬化效应随应变率的增大而减小；此外，修正Johnson-Cook本构模型的拟合结果与实验结果吻合很好，能够很好表征材料的动态力学行为，且考虑材料中应变率力学特性可提高本构模型参量的准确性。

Dynamic mechanical properties of 2A16-T4 aluminum alloy at wide-ranging strain rates

In order to study the dynamic mechanical properties of 2A16-T4 aluminum alloy,experiments for the alloy at quasi-static,intermediate,and high strain rates were performed using an electronic multi-purpose testing machine,a high velocity hydraulic servo-testing machine and a split Hopkinson press bar (SHPB) at room temperature,and the stress-strain curves at different strain rates were obtained,with a modified Johnson-Cook constitutive model fitted.The dynamic mechanical properties at intermediate strain rates and its influence on the constitutive model's parameters were analyzed.The results show that the strain rate hardening effect on the 2A16-T4 aluminum alloy is not obvious between 10-4 ～102 s-1,but it is obvious between 102 ～103 s-1,decreasing with the increase of the plastic strain.In addition,this effect is obvious between 10-4 ～103 s-1,decreasing with the increase of the strain rate.Moreover,the fitted results of modified Johnson-Cook constitutive model agree well with the experiment results,representing well the alloy's dynamic mechanical properties,which can improve the precision of the model's rate-sensitive parameters over a wide range of strain rates.