Characterization of A390 aluminum alloy produced at different slow shot speeds using vacuum assisted high pressure die casting  

不同慢压射速度高真空压铸制备A390铝合金及其性能表征（英文）

作　　者：Wen-bo YU Zi-hao YUAN Zhi-peng GUO Shou-mei XIONG 于文波;袁梓豪;郭志鹏;熊守美(清华大学材料科学与工程学院,北京100084;清华大学先进成形制造教育部重点实验室,北京100084)

机构地区：[1]School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China [2]Key Laboratory for Advanced Materials Processing Technology, Ministry of Education,Tsinghua University, Beijing 100084, China

出　　处：《Transactions of Nonferrous Metals Society of China》2017年第12期2529-2538,共10页中国有色金属学报（英文版）

基　　金：Project(51775297)supported by the National Natural Science Foundation of China;Project(2015M580093)supported by the China Postdoctoral Science Foundation

摘　　要：The effects of vacuum assistance on the microstructure and mechanical properties of high pressure die cast A390alloy at different slow shot speeds were evaluated.Plate-shaped specimens of hypereutectic A390aluminum alloy were produced on a TOYO BD?350V5cold chamber die casting machine incorporated with a self-improved TOYO vacuum system.According to the results,the vacuum pressure inside the die cavity increased linearly with the increasing slow shot speed at the beginning of mold filling.Meanwhile,tensile properties of vacuum die castings were deteriorated by the porosity content.In addition,the average primary silicon size decreased from23to14μm when the slow shot speed increased from0.05to0.2m/s,which has a binary functional relationship with the slow shot speed.After heat treatment,microstructural morphologies revealed that needle-shaped and thin-flaked eutectic silicon particles became rounded while Al2Cu dissolved intoα(Al)matrix.Furthermore,the fractography revealed that the fracture mechanism has evolved from brittle transgranular fracture to a fracture mode with many dimples after heat treatment.对真空辅助不同慢压射速度条件下制备的A390高硅铝合金铸件组织及力学性能进行研究。在装备自行改进TOYO真空系统的TOYO BD-350V5型冷室压铸机上制备片状A390压铸件。结果表明,型腔中的真空度与初始充模阶段慢压射速度呈线性关系。拉伸试验结果表明,试样的拉伸强度随试样内部的孔洞含量升高而降低。另外,当慢压射速度从0.05 m/s增大到0.2 m/s时,初晶Si尺寸由23μm降低到14μm,初晶Si的平均尺寸与慢压射速度存在二元次数关系。经热处理后,初始铸态α(Al)边界上的Al_2Cu因融入Al基体中而大幅减少,并且针状或带状共晶Si球化。断裂形貌表明,断裂形式由热处理前的脆性沿晶断裂转变为热处理后的含有大量韧窝的韧性穿晶断裂。

关 键 词：A390 aluminum shot speed vacuum assisted high pressure die casting (VHPDC) Si distribution tensile strength heat treatment 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG249.2[金属学及工艺—金属材料]