Zr对车身用烧结Al-5Si铝合金组织和力学性能的影响  

Effect of Zr on microstructure and mechanical properties of sintered Al-5Si aluminum alloy for automobile body

作　　者：吴志光[1] 周建民[2] 张方东[1] WU Zhiguang;ZHOU Jianmin;ZHANG Fangdong(Department of Mechanical Engineering,Shanxi Institute of Mechanical and Electrical Engineering,Changzhi 046011,China;China North Industries Group Huaihai Industry Group Co.,Ltd.,Changzhi 046011,China)

机构地区：[1]山西机电职业技术学院机械工程系,山西长治046011 [2]中国兵器工业集团淮海工业集团有限公司,山西长治046011

出　　处：《粉末冶金工业》2021年第1期69-73,共5页Powder Metallurgy Industry

基　　金：山西省高等学校科技创新资助项目(2019L1000)。

摘　　要：通过添加Zr元素的方式提高车身用烧结Al-5Si铝合金的综合性能,采用微观组织测试和慢应变速率拉伸(SSRT)试验等方式对其进行组织和力学性能分析。结果表明:Zr可以抑制再结晶过程,使再结晶晶粒尺寸减小。在Al-5Si-Zr板材内形成了更多的黑色第二相颗粒,再结晶晶粒数量也明显增加。板材内都存在弥散分布第二相组织,具有明显的针形结构,添加Zr之后其数量减少。Zr可以对Al-5Si-Zr板材的淬火空位产生钉扎作用,形成更少的可动空位,使晶界相难以发生形核。板材在NaCl溶液内中相对于空气环境达到了更低拉伸强度与伸长率。添加Zr后,空气中板材拉伸强度从346 MPa减小至321.5 MPa,同时伸长率从原先的12.2%减小至11.41%。Al-5Si-Zr板材断口部位形成了密集分布的韧窝,发生了穿晶韧断的结果,断裂尺寸与深度都发生了降低。The comprehensive properties of sintered Al-5 Si aluminum alloy used for mobile body were improved by adding Zr element.The microstructure and slow strain rate tensile(SSRT)test were used to analyze the microstructure and mechanical properties.The results show that Zr can inhibit the recrystallization process and reduce the recrystallization grain size.More black second-phase particles are formed in Al-5 Si-Zr plate,and the recrystallized grains increases obviously.The second phase structure of dispersion distribution is found in all the plates,which has obvious needle structure,and the number decreases after Zr is added.Zr can nail the quenching vacancy of Al-5 Si-Zr plate,form less movable vacancy,make it difficult for the grain boundary phase to nucleate.The tensile strength and elongation of the plate in NaCl solution are lower than that in the air.After the addition of Zr,the tensile strength of the plate in air decreases from 346 MPa to 321.5 MPa,and the elongation decreases from 12.2%to 11.41%.At the fracture site of Al-5 Si-Zr plate,a dense distribution of dimples is formed,resulting in transgranular ductile fracture,and the fracture size and depth are reduced.

关 键 词：Al-5Si铝合金 ZR 应力腐蚀断裂 显微组织 

分 类 号：U270.41[机械工程—车辆工程] TG146.21[交通运输工程—载运工具运用工程]