摘要
研究焊接温度和转速对半固态搅拌焊接AZ91合金的影响。将Mg-25%Zn中间层夹在两块AZ91板材中间,然后将基体金属和中间层加热至半固态状态。在不同温度和转速下用钻头对焊缝进行搅拌。利用光学显微镜和扫描电子显微镜研究材料的显微组织、空洞形成和偏析。采用硬度分布图和冲剪实验对接头的焊接质量和均匀性进行排序。结果表明,当焊接温度为530°C,转速为1600 r/min时,可得到最低的空洞含量(2.1%)和最高的抗剪强度(188 MPa)。温度和转速过高或太低都使焊接质量和抗剪强度降低。因此,在中等温度和转速下,半固态搅拌焊接可以获得均匀的接头和与基体相近的力学性能。
Semisolid stir welding of AZ91 was investigated with focus on the joining temperature and rotational speed. An Mg-25%Zn interlayer was located between two AZ91 pieces and the system was heated up to the semisolid state of base metal and interlayer. The weld seam was stirred using a drill-tip at different joining temperatures and rotational speeds. Optical and scanning electron microscopes were employedto study microstructure, cavity formation, and segregation. Hardness profile and shear punch test werealso employed to rank the welds based on their quality and homogeneity. Results showed that the lowest cavity content （2.1%） withthemaximum ultimate shear strength （about 188 MPa） was obtained in weld with the joining temperatureof530℃ and the rotational speedof1600 r/min. Low quality welds and a reduction of ultimate shear strength were observed at very high orlow rotational speeds and joining temperatures. The process, in conclusion, produced close mechanical properties to those of thebase metal and homogenous quality throughout the joint, when the intermediate temperature and rotational speeds were employed.
基金
Innovatum (Trollhattan, Sweden) for the financial supporting the researcher in this paper
