摘要
通过四点弯曲应力腐蚀实验对Al-Zn-Mg合金挤压型材包含不同晶粒组织的试样进行应力腐蚀性能测试,并借助金相组织观察、电子背散射衍射以及透射电镜研究晶粒组织不均匀性对材料抗应力腐蚀性能的影响和作用机理。研究结果表明:Al-Zn-Mg合金挤压型材从表面至中心依次分布着粗晶组织、等轴晶组织和纤维状组织,其中粗晶组织和等轴晶组织的厚度分别约为60μm和750μm,再结晶分数和大角度晶界百分占比均从表面至中心逐渐降低;不同晶粒组织的抗应力腐蚀性能主要与晶粒粒度和晶界微观组织有关,相对于粗晶组织和等轴晶组织,纤维状组织由于再结晶行为受到抑制,晶粒粒度较小,大角度晶界较少,具有更离散的晶界析出相和较窄的无沉淀析出带,从而表现出更好的抗应力腐蚀性能。
Stress corrosion cracking(SCC)resistance of the specimens with different grain structures in Al-Zn-Mg alloy extruded profile was investigated through four-point bending test.The relationship and mechanism between grain structure and SCC resistance were studied by means of optical micrograph(OM),electron back scattered diffraction(EBSD)and transmission electron microscope(TEM).The results show that coarse grain structure,equiaxed grain structure and fiber-like structure are distributed from the surface to the center in Al-Zn-Mg alloy extruded profiles.The thickness of coarse grain structure and equiaxed grain structure are about 60μm and 750μm,respectively.The fraction of recrystallization and high angle grain boundary(HAGB)decrease gradually from the surface to the center.The SCC resistance of different grain structures is mainly related to grain size and grain boundary microstructures.Compared with the coarse grain and equiaxed grain structures,the fiber-like structure exhibits better stress corrosion cracking resistance because of the smaller grain size,less high angle grain boundary,more spaced grain boundary precipitates(GBPs)and narrower precipitate free zone(PFZ)caused by limiting recrystallization.
作者
叶凌英
姚学彬
唐建国
李红萍
张新明
YE Lingying;YAO Xuebin;TANG Jianguo;LI Hongping;ZHANG Xinming(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Key Laboratory of Nonferrous Metal Materials Science and Engineering,Ministry of Education,Central South University,Changsha 410083,China;Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,Central South University,Changsha 410083,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第5期1049-1055,共7页
Journal of Central South University:Science and Technology
基金
国家重点研发计划项目(2016YFB0300901)~~
