Diffusion between Ti6Al4V and Cemented Carbide with Different Compositions

Abstract

Titanium alloys have been widely used in the aerospace industry because of their excellent properties, such as light weights, high strengths, and corrosion resistance. In this research, the element diffusion between tungsten–cobalt cemented carbide and Ti6Al4V was analyzed using thermodynamic solution theory. First, it was observed that W, Co, and Ti elements diffused under a high temperature and high pressure. Then, by analyzing the diffusion of the different elements, it was found that the amount and depth of the W and Co elements diffusion from the cemented carbide increased with increases in the Co element content and the WC grain size, while the diffusion of the Ti element decreased with increases in the Co element content and decreases in the WC grain size. It was also found that the diffusion amount and depth of the elements increased with increases in the holding temperature and holding time. Finally, the milling experiment was conducted, and an analysis of the cutting-edge section found the existence of Ti in the cemented carbide substrate, which proved the occurrence of the diffusion phenomenon. No Co was found during a chip analysis, but the W element was there. The higher hardness of the WC grains caused the W element to etch onto the chip surface during the milling experiment.