脉冲电流对钛/铝异种金属熔钎焊界面特征的影响

采用填丝脉冲钨极氩弧焊(P-GTAW)对TA15钛合金与2024铝合金进行焊接试验. 分析脉冲电流对钛/铝异种金属界面结合特性的影响;观察接头厚度方向不同位置Ti/Al界面显微组织特征,并对界面反应层的物相组成和化学元素分布进行分析. 结果表明,采用P-GTAW实现了钛与铝异种金属薄板的对接,钛合金发生微量熔化,与铝合金形成熔钎焊结合;通过采用脉冲电流,改善了Ti/Al界面的能量密度分布,减小了接头厚度方向界面的显微组织差异;由于脉冲电流的作用,减少了Ti/Al界面附近连续脆性金属间化合物的生成,降低了接头的裂纹敏感性,提高了接头的性能.

Effect of pulsed current on interfacial microstructure during welding-brazing of Ti/Al dissimilar alloys

Butt joining of titanium alloy to aluminum alloy Al2024 was conducted using pulsed current gas tungsten arc welding. The influence of pulsed current on Ti/Al interfacial microstructure was studied. The microstructure of Ti/Al interface with different locations were investigated along the depth direction of joint. Element distribution cross the interface was analyzed by EDS. Phase constituent near the interface were determined by XRD. The results indicated that Ti/Al dissimilar alloys were successfully joined using pulsed current gas tungsten arc welding. Titanium was partially melted during welding and a welded-brazed joint was formed. Distribution of welding heat input was improved by the addition of pulsed current. Difference of Ti/Al interface along the thickness direction was mitigated. Formation of continuous brittle intermetallic compound was restricted to a low level due to the effect of pulsed current. Cracking sensitivity of the joint was decreased and performance of the joint was increased.