Al-Mg-Si合金中α-Al(FeMn)Si弥散相和力学性能研究  

Effects ofα-Al(FeMn)Si Dispersoids on Mechanical Properties of Al-Mg-Si Alloys

作　　者：李凯[1,2] 任飞 鲁强 朱凯 李世晨 兰新月[1] 李院斌 吴皇 颜宁 马春德 杜勇 Li Kai;Ren Fei;Lu Qiang;Zhu Kai;Li Shichen;Lan Xinyue;Li Yuanbin;Wu Huang;Yan Ning;Ma Chunde;Du Yong(State Key Laboratory of Powder Metallurgy,Central South University;Institute for Materials Microstructure,Central South University;School of Materials Science and Engineering,Central South University)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083 [2]中南大学高等研究中心材料微结构研究所 [3]中南大学材料科学与工程学院

出　　处：《特种铸造及有色合金》2021年第6期661-668,共8页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(52071340,51820105001,51531009,52074352)。

摘　　要：采用SEM和原位TEM技术研究了均匀化热处理过程中不同Mn含量Al-Mg-Si-Mn-Cu-Fe合金的组织与性能演变,定量阐述了α-Al(FeMn)Si弥散相的形核、长大及粗化行为。利用低电压高分辨SEM的超低穿透深度成像和图像统计分析,精确测定了均匀化热处理过程中弥散相颗粒尺寸逐步增大及其体积分数先增加后降低的峰形变化规律,并阐明了弥散相对合金力学性能的关键影响。研究发现,580℃下进行8 h左右的均匀化热处理可以得到尺寸合适且体积分数最高的弥散相和最优的综合力学性能,过长的热处理时间会导致弥散相粗化从而降低合金的力学性能。此外,添加适量Mn元素(0.5%)并进行均匀化热处理能明显改善合金的抗拉强度与伸长率,但添加过量的Mn元素(0.8%)会引起初生相严重粗化,降低合金的力学性能。The evolution of microstructures and mechanical properties of Al-Mg-Si-Mn-Cu-Fe alloys with different Mn contents during the homogenization heat treatment were investigated by SEM and in-situ TEM.Nucleation,growth and coarsening ofα-Al(FeMn)Si dispersoids were thus quantitatively described.The peak shaped evolution law that dispersoid size is increased gradually and its volume fraction is increased firstly and then decreased during the homogenization heat treatment were measured with high precision,based on ultra-low penetration depth imaging and statistical analysis using low voltage and high resolution.The drastic influence of dispersoids on mechanical properties of alloys was clarified.The results indicate that homogenization heat treatment at 580℃for about 8 h generates the highest volume fraction of dispersoids with adequate size and thus the alloy exhibits optimal comprehensive mechanical properties,while longer treatment leads to coarsening of dispersoids and degradation of mechanical properties.Moreover,the tensile strength and elongation of the alloy can be significantly improved by adding appropriate amount of Mn(0.5%)with homogenization treatment,however,excessive addition of Mn(0.8%)results in serious coarsening of the primary phase,degrading the mechanical properties of the alloy.

关 键 词：AL-MG-SI合金 α-Al(FeMn)Si弥散相 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG113.25[金属学及工艺—金属材料]