爆炸与冲击2018，Vol.38Issue(3)：586-595,10.DOI:10.11883/bzycj-2016-0266
大应变率范围内AM80镁合金的变形行为及组织演变
Deformation behavior and microstructure evolution of an AM80 magnesium alloy at large strain rate range
摘要
Abstract
In order to understand the deformation behavior and microstructure evolution of a solution treated AM80 magnesium alloy under quasi-static and impact loadings,quasi-static and high-speed impact compression tests at room temperature were performed by an Instron universal compression machine and a slip Hopkinson pressure bar apparatus,respectively.Under quasi-static loadings,the flow stress of the AM80 magnesium alloy decreases gradually with the increase of the strain rate (3× 10-5 s-1≤(ε)≤4×10-1 s-1),showing a negative strain rate sensitivity.While,it increases with the increase of the strain rate (7.00× 102 s-1≤(ε)≤5.20× 103 s-1) under impact loadings,demonstrating a significant positive strain rate sensitivity.Basal slip,mechanical twining as well as proper nonbasal slip are the deformation mechanisms for the AM80 magnesium alloy under impact loadings.A larger number of dense tiny mechanical twins under impact loadings are the fundamental reasons for the significantly higher flow stress as compared with that under the quasi-static loadings.In addition,the deformation uniformity of the AM80 magnesium alloy increases significantly as the strain rate increases.When the strain rate increases to 3.65 × 103 s-1,dynamic recovery is detected in the same grains at the location of c,because the softening caused by the adiabatic temperature rise due to localized deformation is greater than the sum of strain hardening and strain rate hardening,which leads to a significant reduction in the density of deformation twins.As a result,the deformation uniformity declines finally.关键词
AM80镁合金/高速冲击/应变率敏感性/Johnson-Cook本构方程/形变孪生Key words
AM80 magnesium/high-speed impact/strain rate sensitivity/Johnson-Cook constitutive equation/deformation twinning分类
数理科学引用本文复制引用
郭鹏程,李健,曹淑芬,徐从昌,刘志文,李落星..大应变率范围内AM80镁合金的变形行为及组织演变[J].爆炸与冲击,2018,38(3):586-595,10.基金项目
国家自然科学基金项目(U1664252) （U1664252）
国家重点研究计划项目(2016YFB0101700) （2016YFB0101700）
