时效工艺对Al-0.55Mg-0.76Si铝合金断裂行为的影响  

Effect of aging process on fracture behavior of Al-0.55Mg-0.76Si aluminum alloy

作　　者：祝哮 李秋梅 王东辉 董刘颖 张伟 代自莹 Zhu Xiao;Li Qiumei;Wang Donghui;Dong Liuying;Zhang Wei;Dai Ziying(Liaoning Zhongwang Group Co.,Ltd.,Liaoyang 111003 China)

机构地区：[1]辽宁忠旺集团有限公司,辽宁辽阳111003

出　　处：《焊接》2024年第8期16-21,共6页Welding & Joining

基　　金：国家重点研发计划(2021YFB3704203)。

摘　　要：【目的】了解时效制度对Al-0.55Mg-0.76Si铝合金挤压型材焊接结构件断裂行为的影响,该文为提高焊接结构件断裂行为提供理论依据。【方法】以Al-0.55Mg-0.76Si铝合金挤压型材焊接结构件为研究对象,经不同时效制度处理,采用金相组织、SEM,EDS,室温拉伸、折弯等检测手段对其断裂行为进行分析。【结果】结果表明,双级时效处理后,第二相明显增多;随着时效时间的延长,第二相出现粗化现象;经微区表面成分分析可知,第二相为Mg,Si相;双级时效制度下的Al-0.55Mg-0.76Si铝合金焊接结构件强度和断后伸长率较单级时效高;断口形貌由塑性-脆性断裂转变为塑性断裂;双级时效制度下的Al-0.55Mg-0.76Si铝合金焊接结构件折弯角度较单级时效高,裂纹由沿晶断裂逐渐转变为穿晶断裂。时效制度为150℃×1 h+180℃×5 h时,强度最高,屈服强度为191.2 MPa,抗拉强度为218.4 MPa;塑性较好,断口形貌为塑性断裂,折弯件外表面裂纹长度变短,为109μm,内表面裂纹为穿晶断裂。【结论】综合分析可知,时效制度为150℃×1 h+180℃×5 h时,Al-0.55Mg-0.76Si铝合金挤压型材焊接结构件强度和塑性最好,为最佳的工艺制度。[Objective]To understand influence of aging system on fracture behavior of welded structural parts of Al-0.55Mg-0.76Si aluminum alloy extruded profiles,this paper provided a theoretical basis for improving fracture behavior of welded structural parts.[Methods]The welded structural parts of Al-0.55Mg-0.76Si aluminum alloy extrusion profiles were taken as the research object,and fracture behavior was analyzed by metallographic structure,SEM,EDS,tensile and bending methods at room temperature.[Results]The results showed that after the two-stage aging treatment,the second phase increased significantly.With the extension of aging time,the second phase appeared coarsening.The second phase was Mg and Si phase according to micro-surface composition analysis.The strength and elongation of Al-0.55Mg-0.76Si aluminum alloy welded structural parts under two-stage aging system were higher than those under single-stage aging,and fracture morphology changed from plastic-brittle fracture to plastic fracture.Bending angle of Al-0.55Mg-0.76Si aluminum alloy welded structural parts under twostage aging system was higher than that under single-stage aging,and crack gradually changed from intergranular fracture to transgranular fracture.When aging system was 150℃×1 h+180℃×5 h,the strength was the highest,yield strength was 191.2 MPa,and tensile strength was 218.4 MPa.The plasticity was better,fracture morphology was plastic fracture,length of crack on the outer surface of bending samples became shorter,which was 109μm,and crack on the inner surface was transgranular fracture.[Conclusion]Comprehensive analysis showed that when aging system was 150℃×1 h+180℃×5 h,the strength and plasticity of Al-0.55Mg-0.76Si aluminum alloy extruded structural parts were the best,which was the best process system.

关 键 词：Al-0.55Mg-0.76Si铝合金 焊接结构件 断裂行为 时效制度 

分 类 号：TG407[金属学及工艺—焊接]