挤压铸造高强韧AlSiMgMn合金的组织和性能  

Microstructure and Properties of High Strength and Toughness AlSiMgMn Alloys Fabricated by Squeeze Casting

作　　者：钟鼓[1,2] 吴永福 邹纯 邱楚[1] 陆萌萌[1] 长海博文 

机构地区：[1]苏州有色金属研究院有限公司 [2]广东鸿图南通压铸有限公司 [3]中铝材料应用研究院有限公司

出　　处：《特种铸造及有色合金》2017年第12期1277-1282,共6页Special Casting & Nonferrous Alloys

基　　金：国家重点研发计划项目(2016YFB0101603)

摘　　要：设计并采用挤压铸造工艺制备了3种高强韧AlSiMgMn合金。利用金相显微镜(OM)、扫描电镜(SEM)和能谱分析(EDS)等手段,研究了合金元素和热处理工艺对挤压铸造AlSiMgMn合金的微观组织和力学性能的影响。结果表明,Sr变质后挤压铸造AlSiMgMn合金中共晶Si变质等级超过AFS 5级,优化的热处理工艺为535℃×4h固溶+160℃×6h时效;当Mg含量从0.3%增加到0.5%,合金的抗拉强度和屈服强度分别增加60 MPa和70 MPa。添加Cu元素的AlSiMgMn合金采用Sb变质,共晶Si变质为AFS 3~4级,虽然热处理后共晶Si相球化良好,但铸造过程中不均匀变质导致颗粒出现团聚。该合金在优化的T6热处理下,抗拉强度为435 MPa,屈服强度为338 MPa,伸长率为7.0%。Effects of alloying elements Mg,Cu and heat treatment on microstructure and mechanical properties of AlSiMgMn alloys fabricated by squeeze casting were investigated by OM,SEM and EDS.For the AlSiMgMn alloys with trace Sr modification,the eutectic silicon modification levels are about grade 5 according to the American Foundry Society（AFS）standard chart for Al-Si alloys.The AlSiMgMn alloys with 0.3% Mg or 0.5% Mg show the same optimized heat treatment parameters：solution at 535 ℃for 4 and aging at 160 ℃ for 6.While the Mg content in AlSiMgMn alloys is increased from 0.3%to 0.5%,the tensile strength and yield strength of the alloy prepared are increased by 60 MPa and 70 MPa,respectively.Replaced Sr with Sb for modification of the AlSiMgMn alloy with 2.5%Cu addition,in consideration of the detrimental effect of Cu on Sr modification,the modification level of eutectic silicon is about grade 3~4.Although eutectic silicon particles could be spheroidized well in the subsequent heat treatment,the particle aggregation occurs obviously because of non-uniform modification effect in the casting process.It is found that strength of squeeze cast AlSiMgMn alloy is improved obviously by Cu addition,where tensile strength,yield strength and elongation of the alloy after T6 treatment reach 435 MPa,338 MPa and 7.0%,respectively.

关 键 词：挤压铸造 强化相 热处理 强度 韧性 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG249.2[金属学及工艺—金属材料]