EFFECTS OF THE ADDITION OF Ti OR Al ON THE WETTING BEHAVIORS AND INTERFACIAL CHARACTERISTICS OF Zr50Cu50 BULK METALLIC GLASS/W SUBSTRATE

In order to get the good performance of metal W reinforced Zr-based bulk metallic glass (BMG) matrix composites, it is necessary to understand the effects of alloy elements on the wettability between Zr-based BMG and W substrate. In this work, the effects of the addition of Ti or Al on the wetting behaviors and interfacial characteristics of Zr50Cu50 BMG on W substrate were studied at different temperatures in a high vacuum by using a sessile drop technique. The SEM and XRD were used to analyze the microstructure and bonding mechanism of the Zr50Cu50 BMG / W interface with the addition of Ti or Al element: The results show that the wetting angle of Zr50Cu50 molten alloy on W substrate decreases with increasing content of Ti or Al in liquid Zr50Cu50 and experimental temperature. The wettability of Zr50Cu50 BMG on W substrates is improved because the surface tension of Zr50Cu50 molten alloy decreases with increasing content of Ti or Al. It is found that the behavior between Zr50Cu50 BMG and W substrate is reactive wetting in nature, and there exists a new ZrW2 phase precipitated in the vicinity of the Zr50Cu50 BMG /W interface. The addition of Ti or Al element has different effects on the microstructure and bonding mechanism of Zr50Cu50 BMG /W interface. On the one hand, the addition of Al element promotes the interfacial reaction. With increasing content of Al, continuous reaction layers of ZrW2 phase in the interface reduce, and there are massive precipitates of Al-rich and Cu-poor phases in molten Zr50Cu50 alloy. On the other hand, the addition of Ti element restrains the interfacial reaction which gradually disappears with increasing content of Ti.