Near-microscopic grain boundary facilitates fatigue crack propagation in a polycrystalline Al–Zn–Mg–Cu alloy  

作　　者：Kai Wen Xiwu Li Baiqing Xiong Haitao Lin Qinghong Wen Yanan Li Hongwei Yan Lizhen Yan Yongan Zhang Zhihui Li Hongwei Liu 

机构地区：[1]State Key Laboratory of Nonferrous Metals and Processes,China GRINM Group Co.,LTD.,Beijing,100088,China [2]GRIMAT Engineering Institute Co.,LTD.,Beijing,101407,China [3]General Research Institute for Nonferrous Metals,Beijing,100088,China [4]Southwest Aluminum(Group)Co.,Ltd.,Chongqing,401326,China

出　　处：《Progress in Natural Science:Materials International》2023年第1期120-125,共6页自然科学进展·国际材料（英文版）

基　　金：supported by the National Key R&D Pro-gram of China (No.2021YFC1910505) and other related projects.

摘　　要：In present study,grain characteristics with sizes within 10-30μm were fabricated from a same Al-Zn-Mg-Cu alloy,FCP behaviors of the alloys with small grain(SG alloy),medium grain(MG alloy)and large grain(LG alloy)were investigated and related fatigue fracture morphology was analyzed.With the enhancement of stress intensity factor range(ΔK),the alloy with larger grains possessed faster FCP rate,which were successively arranged as SG alloy>MG alloy>LG alloy at initial stage while turned to LG alloy>MG alloy>SG alloy at final stage for the stable expanding region.Except for conventional characteristics of striations,tearing ridges,secondary cracks,second phases,voids and dimples,more prominent grain boundary features appeared on fracture surface,espe-cially for MG and LG alloy.The calculation of cyclic plastic zone(CPZ)sizes proved that grain boundary participated and promoted FCP behavior when CPZ covered grain and grain boundary together.

关 键 词：Fatigue crack propagation Grain size Grain boundary Cyclic plastic zone Al-Zn-Mg-Cu alloy 

分 类 号：TG146.21[一般工业技术—材料科学与工程]