Microstructure characteristics of RuTi/1060Al fusion-brazed joint by pulsed gas metal arc welding

Pulsed gas metal arc welding of RuTi titanium alloy to 1060 aluminum was conducted. The microstructure in weld zone of RuTi Ti/1060Al joint was examined by scanning electron microscope (SEM) fitted with energy-dispersive spectrometer (EDS). Elemental distribution and precipitated phase in weld zone and transition region on Ti alloy side were analyzed by EDS. The weld zone was composed of α-Al dendrites and eutectic α-Al+Si structures. The eutectic α-Al+Si structures distributed along the boundaries of α-Al dendrites. Striped or block Ti(Al,Si)₃ intermetallics appeared in the weld zone. A serrated transition region mainly containing Ti(Al,Si)₃ intermetallics was formed between the RuTi titanium alloy and the weld zone. The width of the Ti/Al transition region was less than 10 μm. With the increasing of welding heat input,the Ti/Al transition region presented a rod-like appearance. The heat-affected zone (HAZ) of RuTi titanium alloy consisted of acicular α″ and lath α' martensite. The average microhardness in the HAZ was about 2.16-2.65 GPa.