摘要
用光学显微镜、扫描电镜、透射电镜、常温拉伸以及Kahn撕裂实验等手段,研究了挤压温度对Al-Zn-Mg合金型材表层和中心层强度和断裂韧性的影响。结果表明:挤压型材表层以细小等轴的再结晶晶粒为主,中心层为发生部分再结晶的纤维组织,沿挤压方向中心层强度高于表层,L-T取向的断裂韧性表层高于中心层。挤压温度由440-450℃时升高至480-490℃时动态再结晶程度升高,强度升高,而断裂韧性降低;时效后晶内析出相更细小,晶界析出相粗化、不连续,中心层的再结晶分数由14.8%升高至52.3%,屈服强度也从280 MPa升至314 MPa,而UIE由229 N·mm-1降低至204 N·mm-1。
The effect of extrusion temperature on the tensile properties and fracture toughness of an Al-Zn-Mg alloy was investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy, tensile tests and Kahn tear tests. The results showed that after extrusion the alloy possesses a surface layer composed of fine equiaxed grains with higher toughness in the L- T orientation than that of its center layer, which composed of fiber-like texture and recrystallized grains, while the tensile strength of the center layer is higher than that of the surface layer. When the extrusion temperature increases from 440-450℃ to 480-490℃, the dynamic recrystallization becomes more serious, and the tensile properties and fracture toughness become lower and higher respectively. After aging the precipitates in grains become smaller and the precipitates at grain boundaries are coarsening and discontinuous. Taking the central layer for example, the volume fraction of recrystallized grains increases from14.8% to 52.3%, correspondingly σ0.2increases from 280 MPa to 314 MPa, while UIE decrease from229 N·mm^-1to 204 N·mm^-1.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2016年第2期87-94,共8页
Chinese Journal of Materials Research
基金
国家重点基础研究发展计划2012CB619500资助项目~~
关键词
金属材料
挤压温度
AL-ZN-MG合金
强度
断裂韧性
metallic materials
extrusion temperature
Al-Zn-Mg alloy
tensile properties
fracture toughness
