复杂应力状态下超细晶材料的塑性  

Plasticity of the Ultrafine Grained Materials under Complex Stresses

作　　者：顾阳林 郭亚洲[2] 赵永好[1] 

机构地区：[1]南京理工大学材料科学与工程学院,江苏南京210094 [2]西北工业大学航空学院,陕西西安710072

出　　处：《材料科学与工程学报》2015年第5期714-720,共7页Journal of Materials Science and Engineering

基　　金：杰出青年科学基金资助项目(51225102);国家重点基础研究资助项目(2012CB932203)

摘　　要：本工作通过三维非接触全场应变测量系统(DIC)和有限元模拟(FEM)对比研究了超细晶铜和粗晶铜在拉伸过程中颈缩处的应变和应力分布,比较了在颈缩后的复杂应力状态下超细晶铜和粗晶铜延伸率的差异,实验发现虽然超细晶铜与粗晶铜在工程应力-应变曲线上的断裂延伸率相差较大,但两者颈缩区域的延伸率相当。有限元模拟揭示颈缩区域为三向应力状态,实验设计的缺口试样进一步验证复杂应力状态下超细晶材料的塑性变形能力与粗晶材料相当。复杂应力状态下,超细晶铜内部更多的滑移系被激发,使得超细晶铜的塑性变形能力与粗晶铜相当。Experiments and finite element modeling（FEM）were conducted to give the strain and stress distribution in the necking region of both the ultrafine grained and the coarse-grained copper during the tensile test.Despite the great difference between global elongation to failure,the post-necking elongation of the ultrafine grained copper is comparable with the coarse-grained one.FEM indicates that when necking occurs,the strain is concentrated in the necking region leading to a more complex,triaxial,stress state.A notched tensile test was designed for further study of the plasticity under the complex stress state.The results found that the ultrafine grained copper have comparable plastic capability with their coarse-grained counterparts due to the more activated slip systems under the complex stress state.

关 键 词：颈缩 应力应变分布 复杂应力状态 

分 类 号：TG115.5[金属学及工艺—物理冶金]