Zn含量对Al-Si-Mg合金中Mg_(2)Si时效析出行为的影响  

Effects of Zn Content on the Aging Precipitation Behavior of Mg_(2)Si in Al-Si-Mg Alloy

作　　者：宋东福 曾强 贾义旺[1] 乡家发 张卫文 Song Dongfu;Zeng Qiang;Jia Yiwang;Xiang Jiafa;Zhang Weiwen(Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application,Institute of New Materials,Guangdong Academy of Sciences;National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China University of Technology;Zhaoqing Nandu Recycling Aluminum Co.,Ltd.)

机构地区：[1]广东省科学院新材料研究所,广东省金属强韧化技术与应用重点实验室,广州510650 [2]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510650 [3]肇庆南都再生铝业有限公司

出　　处：《特种铸造及有色合金》2022年第3期323-329,共7页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(52074131);广东省重点研发计划资助项目(2020B010186002);广东省科技计划资助项目(2015B090926013,2019B090905009)。

摘　　要：采用金相显微镜(OM)、扫描电镜(SEM)、拉伸试验机及硬度测试仪,研究了不同Zn含量Al-Si-Zn-Mg合金的微观组织和力学性能。采用差示扫描量热法(DSC)研究了Mg_(2)Si相的时效析出行为,并结合Avrami-Johnson-Mehl(AJM)方程分析了Zn含量对合金时效析出动力学的影响。结果表明,随着Zn含量增加,Al-Si-Zn-Mg合金的峰值时效硬度和强度逐渐提高,伸长率逐渐降低,而峰值时效时间逐渐缩短。Zn均匀地分布在合金中,加Zn对合金的微观组织无明显影响。但Zn阻碍了Mg原子向Si团簇的迁移,提高了Mg-Si溶质原子团簇和G.P.区的析出激活能,并在随后的升温过程中加速了Mg-Si溶质原子团簇和G.P.区的溶解,使得Mg-Si团簇的尺寸减小。同时Zn的加入增加了基体的晶格畸变能,促进了Mg、Si原子从基体迁移形成更多Mg-Si团簇和Mg-Zn-Si团簇,增加了β″相的形核质点,促进了β″相的析出,提高了时效响应速率。The microstructure and mechanical properties of Al-Si-Zn-Mg alloys with different Zn contents were investigated by metallographic microscope(OM),scanning electron microscope(SEM),tensile testing machine and microhardness tester.The effects of Zn contents on aging precipitation behavior of Mg_(2)Si phase in Al-Si-Mg alloy were analyzed by differential scanning calorimetry(DSC),combined with Avrami-Johnson-Mehl(AJM)equation.The results indicate that peak aging strength and hardness of Al-Si-Zn-Mg alloys are gradually increased with the increase of Zn contents,while elongation is decreased and peak aging time is gradually shortened correspondingly.Zn is evenly distributed in the alloy,and addition of Zn has little effect on the microstructure,which,however,improves the precipitation activation energy of Mg-Si solute atomic clusters and G.P.zone by hindering the migration of Mg atoms to Si clusters,and accelerates the dissolution of Mg-Si solute atomic clusters and G.P.zone during the subsequent heating process,resulting in the dimension reduction of Mg-Si clusters.Furthermore,the lattice distortion energy of the matrix is increased,and the migration of Mg and Si atoms from the matrix to form more Mg-Si and Mg-Zn-Si clusters is promoted after Zn addition,which increase the nucleation particles of the β″phase,promoting the precipitation ofβ″phase and aging response rate.

关 键 词：Zn含量 Al-Si-Zn-Mg合金 析出动力学 Avrami-Johnson-Mehl 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG156.92[金属学及工艺—金属材料]