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通过高温拉伸试验研究TC4钛合金激光对接接头超塑性变形,用金相显微镜观察了超塑性变形前后母材及焊缝显微组织,并测量了变形前后焊缝截面的显微硬度。结果表明:激光焊接接头能够承受高温拉伸,随着变形温度的提高或应变速率的降低,母材晶粒发生一定程度的长大,β与α两相比增加。在高温超塑性变形作用下,焊缝的针状组织增厚成为片层状,并发生局部区域球化。激光焊接接头性能优良,超塑性变形后焊缝截面显微硬度约380HV。
The superplastic deformation of the TC4 titanium butt joint was studied by high temperature tensile test. The microstructure of the parent material and the weld before and after superplastic deformation was observed with a metallographic microscope. The microhardness of the cross section before and after the deformation was measured. The results show that the laser welded joints can withstand high temperature tensile. With the increase of the deformation temperature or the decrease of the strain rate, the base metal grains grow to a certain degree, and β and α increase. Under the action of high temperature superplastic deformation, the acicular tissue of the weld thickened into a lamellar shape, and localized area spheroidization occurred. Laser welding joint performance, superplastic deformation of the weld micro-hardness of about 380HV.