晶粒位向对AZ31挤压板材Hall-Petch关系的影响  

Influence of Grain Orientation on Hall-Petch Relationships for Extruded AZ31 Plate

作　　者：季芸 李德江[1] 曾小勤[1] 丁文江[1] 

机构地区：[1]上海交通大学材料科学与工程学院,轻合金精密成型国家工程研究中心,上海200240

出　　处：《材料科学与工程学报》2018年第1期15-20,34,共7页Journal of Materials Science and Engineering

基　　金：国家重点研发计划资助项目(2016YFB0301002); 国家自然科学基金资助项目(51131107)

摘　　要：本文研究了AZ31镁合金挤压板材热处理后不同晶粒尺寸下各角度的拉伸性能与变形行为,通过分析拉伸曲线和变形后的位错类型来确定不同角度下的拉伸变形机制。结果发现:沿板材法向0°,22.5°,45°,67.5°,90°拉伸后的屈服强度与晶粒尺寸符合Hall-Petch(H-P)关系,但H-P参数值各不相同,0°具有最高的σ_0和最低的K_y,其变形机制由拉伸孪晶为主导与棱柱面<a>滑移共同作用;45°拉伸时具有最低的σ_0和最高的K_y,变形机制为基面<a>滑移主导;90°下的H-P参数值与0°相接近,<c>位错及<a+c>位错开始出现,棱柱面滑移与拉伸孪晶共同主导变形机制,孪晶可以协调变形改变晶粒取向和促进非基面滑移的产生。Tensile properties and deformation behaviors were investigated along different direction（angle）of the annealed AZ31 extruded plate.Then dislocation types were analyzed to confirm the deformation modes at different angles.The results show that the yield strength and grain size at different angle,θ,between the tensile loading direction and normal direction of the plate,namely 0°,22.5°,45°,67.5°,90°,obeys H-P relationship while their parameters are different.The parameter values at 0° had the highest friction stess,σ_0,and the lowest strength coefficient,K_y,dominated by extension twin and prismatic slip.At 45°,it had the lowest σ_0 and highest K_y,dominated by basal slip.c and a＋c dislocation emerged at 90° and the parameters were dominted by the co-work of prismatic slip and extension twin whose values close to the 0°.Besides,extension twin can change the grian orientation to coordinate deformation and help to activate non-basal slip.

关 键 词：镁合金 变形行为 拉伸孪晶 位错 滑移 

分 类 号：TG146.22[一般工业技术—材料科学与工程]