7075铝合金铸锭组织及均匀化研究  

Microstructure and Homogenization Treatment of 7075 Aluminum Alloy Ingot

作　　者：李承波[1,2,3] 韩素琦 何克准[1] 唐露华[1] 刘胜胆[2,3] 张新明[1,2,3] 

机构地区：[1]广西南南铝加工有限公司 [2]中南大学轻合金研究院 [3]中南大学有色金属先进结构材料与制造协同创新中心

出　　处：《特种铸造及有色合金》2016年第12期1248-1252,共5页Special Casting & Nonferrous Alloys

基　　金：国家重点基础研究发展计划(973计划)资助项目(2012CB619501);国家国际科技合作专项资助项目(2014DFA50210)

摘　　要：采用光学显微镜察、扫描电镜(SEM)和透射电镜(TEM)观察等分析方法,研究了7075铝合金铸锭组织及均匀化工艺。结果表明,Al-Zn-Mg-Cu-Cr合金的铸态凝固组织由Al基体+Mg(Zn,Al,Cu)2非平衡共晶相组成;均匀化温度在460℃时,合金中枝晶组织部分消失,低熔点相溶解不充分,在470℃均匀化出现过烧现象。合金经460℃×5h+480℃×24h和460℃×5h+490℃×24h均匀化之后,晶界处的共晶组织基本消除,但晶粒显著长大,两种双级均匀化的晶粒尺寸分别约为120μm和150μm。用400℃×5h+460℃×24h+470℃×24h三级均匀化后,基本消除了共晶组织,均匀化效果很好且晶粒尺寸约为75μm,是最佳的均匀化制度。The homogenization process and microstructure of 7075 alloy ingot were analyzed by optical microscopy（OM）,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.The results show that the microstructure of Al-Zn-Mg-Cu-Cr alloy ingot consists of Al matrix and Mg（Zn,Al,Cu）2non-equilibrium eutectic phase.With homogenized at 460 ℃,the dendritic structure in the alloy disappears partly,and low melting point phases is dissolved insufficiencily,so alloy constituent exhibits unevenly diffusion,while with homogenized at 470 ℃,part of structure is overburned.After homogenized at 460℃×5h＋480℃×24hand 460℃×5h＋490℃×24h,the eutectic structure at grain boundary are bascally eliminated,however,grain size is grew up obviously,where the final grain size of the alloy at two homogenizing treatments reaches 120μm and 150μm,respectively.After treated at 400℃×5h＋460 ℃×24h＋470 ℃×24h,the eutectic structures is totally dissolved,and grain size is about 75μm.It is indicated that the three level homogenization treatment is desirable for treating Al-ZnMg-Cu-Cr alloy.

关 键 词：7075合金 均匀化 微观组织 

分 类 号：TG292[金属学及工艺—铸造]