焊后热处理对TC4钛合金线性摩擦焊接头组织和性能的影响
Effect of Post-weld Heat Treatment on Microstructure and Mechanical Properties of Joint of TC4 by Linear Friction Welding
季亚娟， 张田仓， 李晓红
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作者单位：（中航工业 北京航空制造工程研究所，北京100024）
中文关键字：线性摩擦焊； 钛合金； 组织； 性能
英文关键字：linear friction welding; titanium alloy; microstructure; mechanical property
中文摘要： 在前期焊接试验参数优化基础上，通过自行研制的线性摩擦焊机焊接了两组TC4钛合金试件，其中对一组试件焊后进行630 ℃× 3 h的热处理，然后对焊态和热处理态焊接接头的组织和力学性能进行了对比分析。结果表明，焊态下接头组织更为细小；热处理态接头组织中析出了次生α相，且晶粒发生球化长大现象，接头组织更加均匀。对两种接头在室温和400 ℃条件下进行拉伸试验，接头拉伸断裂位置均在母材处，且室温拉伸条件下热处理接头的抗拉强度和屈服强度均较焊态接头的高，高温拉伸条件下两种接头拉伸性能相差不大。400 ℃、570 MPa条件下两种接头的持久时间均超过100 h。
英文摘要：On the basis of previous welding experiments, TC4 specimens were welded by self-made linear friction welding machine. After welding, one specimen was heat-treated at 630℃ for 3 h. Then, the microstructure and mechanical property was analyzed. The results show that the microstructure of as-welded joint is more fine. The secondary α phase precipitates in the heat-treated structure, the grains spheroidize and coarsen, the microstructure of the welded joint is more homogeneous. The tensile test of the welded joint is done at roon-temperature and 400 ℃, the fracture positions are all in the base metal. The extension and yield strength of the welded joint at room temperature is higher compared with the as-welded joint, but the extension and yield strength at 400 ℃ has no difference. Under the condition of 400 ℃, 570 MPa, the endurance time of as-welded joint and post-weld heat-treated joint all exceeds 100 h.