Cu含量和热处理工艺对Al-Si-Mg-Mn-xCu铸造铝合金显微组织和力学性能的影响  

Effects of Cu content and heat treatment process on microstructures and mechanical properties of Al−Si−Mg−Mn−xCu cast aluminum alloys

作　　者：贾志宏 周广文[2] 周宏宇 刘飞 丁立鹏 翁瑶瑶 向开云 赵海东 Zhi-hong JIA;Guang-wen ZHOU;Hong-yu ZHOU;Fei LIU;Li-peng DING;Yao-yao WENG;Kai-yun XIANG;Hai-dong ZHAO(Key Laboratory for Light-weight Materials,Nanjing Tech University,Nanjing 211816,China;College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China;School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013,China;National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510640,China;School of Materials Science and Engineering,Nanjing Institute of Technology,Nanjing 211167,China)

机构地区：[1]南京工业大学先进轻质高性能材料研究中心,南京211816 [2]重庆大学材料科学与工程学院,重庆400044 [3]江苏大学材料科学与工程学院,镇江212013 [4]华南理工大学国家金属材料近净成形工程技术研究中心,广州510640 [5]南京工程学院材料科学与工程学院,南京211167

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第3期737-754,共18页中国有色金属学报（英文版）

基　　金：financially supported by the National Key Research and Development Program of China (No. 2020YFA0405903);the National Natural Science Foundation of China (Nos. 52001159, 52101141);the Natural Science Foundation of Jiangsu Province;China (No. BK20202010)。

摘　　要：采用三维X射线显微镜、光学显微镜、扫描电子显微镜、透射电子显微镜及硬度测试系统研究Cu含量及热处理工艺对真空压铸Al-Si-Mg-Mn-xCu合金显微组织和力学性能的影响。研究发现,虽然Cu含量增加会提高铸锭中气孔的密度和尺寸,但是Cu添加将促进凝固过程中含Cu初生相(Q-Al_(5)Cu_(2)Mg_(8)Si_(6)和θ-Al_(2)Cu)的形成,从而提高合金性能。合金中形成5种不同结构的初生相,包括共晶Si、α-Al(Fe,Mn)Si、β-Mg_(2)Si、Q-Al_(5)Cu_(2)Mg_(8)Si_(6)和θ-Al_(2)Cu相。随着Cu含量增加,θ相的面积分数迅速增加,α-Al(Fe,Mn)Si相面积分数首先降低,随后缓慢增加,而Q相的变化趋势与α-Al(Fe,Mn)Si相相反。这些初生相在热处理过程中会出现不同的演变规律。在随后的时效处理过程中,Q'和θ'相的协同析出能显著提高合金的时效硬化潜力。The effects of Cu content and heat treatment process on the microstructures and mechanical properties of a series of Al-Si-Mg-Mn-xCu cast aluminum alloys prepared by the vacuum die casting process were investigated by three-dimensional X-ray microscopy,optical microscopy,scanning electron microscopy,transmission electron microscopy and microhardness testing.It was found that the number density and size of gas porosities increase with increasing Cu content.However,the Cu addition will promote the formation of Cu-containing primary phases(Q-Al_(5)Cu_(2)Mg_(8)Si_(6) andθ-Al_(2)Cu)during the solidification,which will improve the properties of the alloys.Five different primary phases were observed,namely eutectic Si,α-Al(Fe,Mn)Si,β-Mg_(2)Si,Q-Al_(5)Cu_(2)Mg_(8)Si_(6),andθ-Al_(2)Cu phases.With increasing the Cu content,theθphase area fraction increases significantly,while theα-Al(Fe,Mn)Si phase area fraction decreases initially,followed by a slight increase,with the Q phase area fraction displaying the opposite trend relative toα-Al(Fe,Mn)Si phase.These primary phases present different evolution rules during heat treatment process.During subsequent aging,the synergic effect of precipitating Qʹandθʹphases can significantly increase the alloy hardening response.

关 键 词：铝硅铸造合金 真空压铸 热处理 显微组织 力学性能 初生相 

分 类 号：TG156[金属学及工艺—热处理] TG146.21[金属学及工艺—金属学]