液态模锻2A50铝合金轮毂宏观缺陷、微观组织和力学性能研究  

Study on Macroscopic Defects,Microstructure and Mechanical Properties of 2A50 Aluminum Alloy Wheel Hub by Molten Metals Die Forging

作　　者：武彤 邢书明[1] 刘鑫 WU Tong;XING Shuming;LIU Xin(School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学机械与电子控制工程学院,北京100044

出　　处：《常州大学学报（自然科学版）》2021年第6期8-16,共9页Journal of Changzhou University：Natural Science Edition

摘　　要：使用液态模锻工艺生产2A50铝合金轮毂。采用光学金相显微镜,电子拉伸试验机等手段,对不同液锻机压力下的2A50轮毂宏观缺陷、微观组织及力学性能进行了研究。结果表明:随着压力的增大,轮毂直臂上沿冷隔白层厚度与拐角处鼓泡直径均有所减小;2A50合金微观组织以初生α-Al为基体,铸态组织有着典型的细小树枝晶状组织形貌,并伴随有较为粗大的等轴树枝晶组织形貌,热处理组织主要呈等轴晶形貌。当压力由80 MPa增至118 MPa时,底部与直壁处的铸态与热处理组织中初生α-Al等轴晶平均尺寸减小幅度37~52μm;轮毂底部铸态拉伸试棒抗拉强度、断后伸长率与压力无明显相关性,当压力由80 MPa增至118 MPa时,底部与直壁处热处理拉伸试棒抗拉强度分别提升13.3 MPa与18 MPa,断后延伸率分别提升1.43%与2%。2A50 aluminum alloy wheel hub was produced by molten metals die forging(MMDF for short).The macroscopic defects,microstructure and mechanical properties of 2A50 wheel hub under different forging pressure were studied by means of optical microscope and electronic tensile testing machine.The results show that the white layer thickness of the cold barrier along the straight arm and the diameter of the bubble at the corner of the hub decreased with the increase of the pressure.The microstructure of 2A50 alloy is composed of primaryα-Al matrix.The as-cast microstructure has typical fine dendritic morphology,accompanied by coarse equiaxed dendritic morphology.The heat-treated microstructure mainly presents equiaxed crystal morphology.After the pressure increased from 80 MPa to 118 MPa,the average size of primaryα-Al equiaxed grains at the bottom and straight arm decreased by 37—52μm.There is no obvious correlation between the tensile strength and the elongation after fracture of the as-cast tensile test bar at the bottom of hub and the pressure.After the pressure increased from 80 MPa to 118 MPa,the tensile strength of the heat-treated tensile test bars at the bottom and straight arm increased by 13.3 MPa and 18 MPa respectively,the elongation after fracture increases by 1.43%and 2%respectively.

关 键 词：液态模锻 2A50铝合金 负重轮轮毂 宏观缺陷 微观组织 力学性能 

分 类 号：TG316.3[金属学及工艺—金属压力加工]