|Effect of Si on Ti/Al brittle interfacial phases and microstructural evolution of pulsed current gas tungsten arc welding joints|
LIU, K., LI, Y., WANG, J., WEI, S., ZHOU, Y.
vol. 54 (2016), no. 2, pp. 97 - 105
The effect of Si on brittle interfacial phases and microstructural evolution of Ti/Al joints was investigated during pulsed current gas tungsten arc welding (PCGTAW) with filler wires. Interfacial microstructure and phase constituents were characterized by an optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The microstructural evolution mechanism was revealed from the perspective of the thermodynamics. It was found that the layered microstructure consisted of various Ti-Al or Ti-Si intermetallic compounds (IMCs). The effect of silicon on the reaction mechanism of fusion-welding interface mainly included that the formation of Ti5Si3 consumed most molten titanium and suppressed the reaction of titanium with aluminum. Moreover, the Ti5Si3 distributing at the grain boundary contributed to the forming of discontinuous TiAl3. The effect of silicon on the reaction mechanism of brazed interface was mainly reflected by silicon in the reaction of titanium with aluminum and the forming of Ti(AlxSi1–x)3.
effect of Si, interface, microstructural evolution, welding, Ti/Al
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