Abstract Microstructural observations of cross sections of butt joints of Ti-22Al-25Nb (at.%) alloy manufactured using ultrasonic pulse frequency tungsten inert gas welding method at different welding parameters without and with welding wire, the butt joint at 50 KHz pulse frequency with welding wire has the largest equiaxed crystal zone, finest columnar crystals, and improves damage of dendritic crystals and overburning. The tensile strength, yield strength and elongation of butt joint at 50 KHz welding frequency with welding wire are the highest, compared with those of butt joints at other welding parameters without welding wire, and the fracture of it is ductile fracture mode of dimples. Further, fusion zone composed of α2 + β/B2 two phases and heat affected zone composed of α2 + O + β/B2 three phases in the butt joint having the highest tensile strength are determined using X-ray diffraction technology. In this butt joint, the microhardness of heat affected zone is the highest, followed by that of base material, fusion zone lowest.

中文翻译：

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超声波脉冲频率钨惰性气体焊接Ti-22Al-25Nb(at.%)合金对接接头的显微组织和力学性能

摘要 采用超声波脉冲频率钨极惰性气体保护焊方法制造的 Ti-22Al-25Nb (at.%) 合金对接接头横截面的显微组织观察，在不同焊接参数下，无焊丝和有焊丝，50 KHz 脉冲频率下的对接接头焊丝等轴晶区最大，柱状晶最细，改善枝晶损伤和过烧。有焊丝的对接接头在50 KHz焊接频率下的抗拉强度、屈服强度和伸长率与无焊丝的其他焊接参数的对接接头相比最高，其断裂为韧窝韧性断裂模式。更多，采用X射线衍射技术确定对接接头中抗拉强度最高的α2+β/B2两相组成的熔合区和α2+O+β/B2三相组成的热影响区。在该对接接头中，热影响区显微硬度最高，母材次之，熔合区最低。