In the present study, a copper modified titanium alloy (Ti–6Al–4V–2.5Cu) was prepared by using vacuum arc re-melting and processed successfully by hot forging and rolling. The alloy was subjected to solution treatment (ST) at two temperatures, viz. 900 °C and 1010 °C followed by low temperature ageing at 500 °C. The weldments were fabricated from the alloy by using gas tungsten arc welding (GTAW) in continuous current (CC) and pulsed current (PC) modes. The effect of heat treatment and welding mode with and without post weld heat treatment (PWHT) on microstructure, hardness and tensile properties has been studied and compared. Pulsing of current during GTAW prompted in refinement of grains. While CC weldments showed coarser columnar grains, PC weldments reveal finer equiaxed β grains. Ageing and PWHT caused the formation of Ti₂Cu intermetallic precipitates in the base alloy as well as in weldments. While the grain refinement in PC weldments manifested in higher strength and percent elongation relative to that of CC weldments, the higher improvement of strength in PWHT condition is due to the combination of both grain refinement and presence of Ti₂Cu precipitates. However, the base metal evidenced the better strength properties in both heat treatment conditions than the weldments.

在本研究中，使用真空电弧重熔制备了铜改性钛合金（Ti-6Al-4V-2.5Cu），并通过热锻和轧制成功进行了加工。合金在两个温度下进行固溶处理（ST）。900°C和1010°C，然后在500°C进行低温老化。焊件是通过在连续电流（CC）和脉冲电流（PC）模式下使用钨极氩弧焊（GTAW）制成的。研究并比较了采用和不采用焊后热处理（PWHT）的热处理方式和焊接方式对组织，硬度和拉伸性能的影响。GTAW期间的电流脉冲促使晶粒细化。CC焊件显示出较粗的柱状晶粒，而PC焊件显示出更细的等轴β晶粒。时效和PWHT引起Ti的形成₂ Cu金属间化合物在基础合金以及焊件中析出。尽管PC焊件中的晶粒细化表现出比CC焊件更高的强度和伸长率，但PWHT条件下强度的更高改善是由于晶粒细化和Ti ₂ Cu析出物的结合。但是，在两种热处理条件下，母材都具有比焊接件更好的强度性能。