喷射沉积过共晶AlSiCuMg合金的时效行为和力学性能  

Ageing behavior and mechanical properties of spray deposited hypereutectic AlSiCuMg alloy

作　　者：冯迪[1] 李鑫迪 吴彩虹 林慧颖 朱田 王萍 叶凌英[2] 张新明[2] LEE Yunsoo FENG Di;LI Xing-di;WU Cai-hong;LIN Hui-ying;ZHU Tian;WANG Ping;YE Ling-ying;ZHANG Xin-ming;LEE Yunsoo(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,China;School of Materials Science and Engineering,Central South University,Changsha 410083,China;Metallic Materials Division,Korea Institute of Materials Science,Changwon 51508,Republic of Korea)

机构地区：[1]江苏科技大学材料科学与工程学院,镇江212003 [2]中南大学材料科学与工程学院,长沙410083 [3]Metallic Materials Division,Korea Institute of Materials Science,Changwon 51508,Republic of Korea

出　　处：《中国有色金属学报》2023年第5期1399-1412,共14页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51801082);镇江市重点研发计划资助项目(GY2021003,GY2021020);江苏省大学生创新创业计划资助项目(202210289112Y);江苏省研究生创新创业计划资助项目(KYCX21_(3)453)。

摘　　要：利用扫描电镜(SEM+EBSD)、透射电镜(TEM)、硬度测试以及室温拉伸实验研究了喷射沉积过共晶AlSiCuMg合金的时效组织演变规律及力学性能。结果表明:随时效时间的延长,喷射沉积AlSiCuMg合金的硬度先增加后降低;随着时效温度的升高,合金硬度达到峰值所需时间分别为24 h(170℃)、2 h(185℃)和0.5 h(200℃)。合金经185℃时效0.5 h后,在位错处可观察到非均匀析出的细小针状θ″相。在(185℃,2 h)峰时效状态下,析出相包含细针状θ″相和点状Q′相,同时存在粗针状θ′相。峰时效硬度约为91HRB,比挤压态提高了近72%。合金经185℃时效28 h后,θ′相体积分数明显增加。合金经185℃时效48 h后,析出相演变为粗大的板条状θ相和方块状Q相;过剩Si相开始析出,同时在与入射轴垂直的晶面上观察到包围Si相的粗大盘片状富Cu相。合金经185℃时效56 h后,θ相和Q相演变为粗大椭球状。合金的硬度下降至约80HRB。喷射沉积AlSiCuMg合金的时效析出惯序为:过饱和固溶体→GP区→θ″+Q′→θ′+Q′→θ+Si+Q′→θ+Si+Q。合金的峰值时效强化效应来自细小θ″和Q′相对位错的阻碍作用。(185℃,2 h)峰时效态抗拉强度可达447 MPa。The evolution of microstructure and mechanical properties during ageing process of spray deposited hypereutectic AlSiCuMg alloy were investigated by scanning electron microscopy(SEM+EBSD),transmission electron microscopy(TEM),hardness test and room temperature tensile test.The results show that the hardness of spray deposited AlSiCuMg alloy first increases and then decreases with the ageing time.With the increase of ageing temperature,the time required to reach the peak hardness is 24 h(170 ℃),2 h(185 ℃) and 0.5 h(200 ℃),respectively.After being aged at 185 ℃ for 0.5 h,the precipitation behavior is inconspicuous,and only few fine θ″ precipitates can be observed on the dislocation.After being peak aged at 185 ℃ for 2 h,the precipitates consist of needle like θ″ phase and dot like Q′ phases.A few thick needle like θ' phases appear.The peak hardness level is about 91HRB,which is 72% higher than that of the extruded state.After being aged at 185 ℃ for 28 h,the volume fraction of θ′ phase increases significantly.After being aged for 48 h,the strip like θ phases and lath like Q phases with larger size can be observed.In addition,the excess Si begins to precipitate,and the coarsened disk-shaped Curich phase surrounding the Si appears on the crystal plane which is perpendicular to the tensile axis direction.Continue ageing to 56 h,θ phase and Q phase both evolve into the coarsened state and show an ellipsoid-like shape.The hardness of the alloy decreases to about 80HRB at(185℃,56 h) condition.The ageing precipitation sequence of the spray deposited AlSiCuMg alloy is supersaturated solid solution→GP zone→θ″+Q′→ θ′+Q′→θ+Si+Q′→θ+Si+Q.The strengthening effect of peak aged state mainly results from the resistance of the high density θ″ and Q′ phase to the movement dislocation.The tensile strength under(185 ℃,2 h) peak ageing state can reach to 447 MPa.

关 键 词：喷射沉积 过共晶合金 AlSiCuMg合金 时效 θ相 Q相 

分 类 号：TG1[金属学及工艺—金属学]