铸造方式对A356铝合金组织、热导率和力学性能的影响  

Effects of Casting Methods on Microstructure,Thermal Conductivity and Mechanical Properties of A356 Aluminum Alloy

作　　者：曹杨婧 李元东[1,2] 罗晓梅[1] 毕广利[1,2] 宋赵熙 李想[1] 樊博阳 Cao Yangjing;Li Yuandong;Luo Xiaomei;Bi Guangli;Song Zhaoxi;Li Xiang;Fan Boyang(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology;Key Laboratory of Nonferrous Metal Alloy and Processing, Ministry of Education, Lanzhou University of Technology)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室 [2]兰州理工大学有色金属合金及加工教育部重点实验室

出　　处：《特种铸造及有色合金》2021年第11期1424-1430,共7页Special Casting & Nonferrous Alloys

基　　金：国家重点研发计划资助项目(2018YFB2001800)。

摘　　要：以商用A356铝合金为对象,研究铸造方式(金属型铸造、液态挤压铸造、半固态挤压铸造)对其组织、热导率和力学性能的影响。结果表明,液态和半固态挤压铸造显著减少铸造缺陷,提高合金的致密性。其中,液态挤压铸造制件相较于金属型铸造晶粒明显细化,共晶Si相从粗大的板条状转变为长杆状,合金抗拉强度由179.930 MPa提高到209.446 MPa,伸长率从3.19%提高到6.93%,硬度(HB)由55提高到64,热导率由150.064 W/(m·K)升高到153.072 W/(m·K);经半固态挤压铸造后,初生α-Al晶粒分布均匀,形状圆整。共晶Si相尺寸减小,边界圆钝,偏析消除。合金抗拉强度为223.514 MPa,伸长率达到13.68%,硬度(HB)为71,热导率提高到160.220 W/(m·K)。The effects of casting methods(permanent mould casting,liquid squeeze casting,semi-solid squeeze casting) on microstructure,thermal conductivity and mechanical properties of commercial A356 aluminum alloy were investigated.The results indicate that liquid and semi-solid squeeze casting can significantly reduce defects of casting,increasing the densification of alloy.Thereinto,the grain of the liquid squeeze castings is obviously refined compared with the permanent mould casting ones,where the eutectic Si phase is converted from the coarse lath shape to the long rodlike shape.The tensile strength of the alloy is increased from 179.930 MPa to 209.446 MPa,the elongation from 3.19% to 6.93%,the hardness(HB) from 55 to 64,and the thermal conductivity from 150.064 W/(m·K) to 153.072 W/(m·K).After semi-solid squeeze casting,the primary α-Al grains are evenly distributed with round shape.The size of eutectic Si phase with round and blunt boundary is also decreased,and segregation is eliminated.The tensile strength,elongation,hardness(HB) and thermal conductivity of the alloy reach 223.514 MPa,13.68%,71 and 160.220 W/(m·K),respectively.

关 键 词：A356铝合金 半固态挤压铸造 热导率 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG249.9[金属学及工艺—金属材料]