大型非等厚7075铝合金自由锻件残余应力消减研究  

Residual stress reduction of large non-equal thickness free forging part of 7075 aluminum alloy

作　　者：蒋小娟 李坤宏[1] 袁程 孙涛 滕海灏 滕树满 JIANG Xiaojuan;LI Kunhong;YUAN Cheng;SUN Tao;TENG Haihao;TENG Shuman(School of Mechanical Engineering and Automation,Chongqing Industry Polytechnic College,Chongqing 401120,China;Wuhan Mechanical Technology Institute Co.Ltd,Wuhan 430000,China;School of Materials Science and Engineering,Chongqing University,Chongqing 400044,China;Liuzhou Steel Group,Liuzhou 545000,China)

机构地区：[1]重庆工业职业技术学院机械工程与自动化学院,重庆401120 [2]武汉工控艺术制造有限公司,湖北武汉430000 [3]重庆大学材料科学与工程学院,重庆400044 [4]广西柳州钢铁集团有限公司,广西柳州545000

出　　处：《兵器材料科学与工程》2022年第5期108-115,共8页Ordnance Material Science and Engineering

基　　金：重庆市自然科学基金面上项目(cstc2021jcyj-msxmX1112)。

摘　　要：制定合理的热处理工艺及消除热处理后的残余应力是保证7075铝合金综合性能的关键因素。用Jmatpro热力学计算软件分析铝合金平衡相成分、TTT(等温转变曲线)、CCT曲线(连续转变曲线);用扫描电子显微镜及电子背散射衍射技术(EBSD)对固溶处理后的析出相及晶粒尺寸进行分析;用Deform-3D软件模拟分析大型自由锻件淬火残余应力,并探究分步冷压对消减大型锻件残余应力的影响。结果表明:7075铝合金在室温下的平衡相主要包括α(Al)、η(MgZn)、S(Al_(2)CuMg)和Al_(6)Mn等相,其中η、S相为主要强化相,最佳固溶温度为460~490℃,淬火过程中由于锻件心部冷却速度较小,会析出部分η′相。分步冷压对消除残余应力效果明显,且冷压量为3%时,淬火残余应力消减率较高,应力分布更均匀。Establishing reasonable heat treatment process and eliminating residual stress after heat treatment were the key factorsto ensure the comprehensive properties of 7075 aluminum alloy.Jmatpro thermodynamic calculation software was used to analyzethe equilibrium phase composition,and also used to calculate the TTT and CCT curves of aluminum alloy.The precipitates andgrain size after solution treatment were analyzed by scanning electron microscopy and electron backscatter diffraction(EBSD).Deform-3D software was used to simulate and analyze the quenching residual stress of large free forgings,and the effect of stepcold pressing on reducing the residual stress of large forgings was investigated.The results show that the equilibrium phasecompositions of 7075 aluminum alloy at room temperature mainly includeα(Al),η(MgZn2),S(Al_(2)CuMg)and Al_(6)Mn,amongwhichηand S are the main strengthening phases.The optimal solution temperature is 460-490℃.Part ofη′phase can beprecipitated during quenching due to the low cooling rate of forging core.Step cold pressing has obvious effect on eliminatingresidual stress,the quenching residual stress reduction rate is higher and the stress distribution is more uniform when the coldpressure is 3%.

关 键 词：7075铝合金 自由锻件 热处理工艺 残余应力 

分 类 号：TG319[金属学及工艺—金属压力加工]