Diffusion wear in dry cutting of Ti–6Al–4V with WC/Co carbide tools

The element diffusion from the Ti–6Al–4V titanium alloy to WC/Co carbide tools (vice versa) at temperatures up to 800 °C was examined. The morphology of the diffusion couples was detected by SEM. Dry turning tests on Ti–6Al–4V alloy were carried out with WC/Co carbide tools. Results showed that W and Co elements did not greatly penetrate into the Ti–6Al–4V alloy at 400 °C; while at 600 °C, W and Co diffused a long way into the Ti–6Al–4V alloy, and the penetrating depth reached 20 μm at 800 °C. The hardness near the interface of the diffusion couples is lower than those far away from the interface owing to element diffusions. The element diffusion from the Ti–6Al–4V to the WC/Co carbide tools (vice versa) through the tool–chip interface in machining processes leads to a composition change of the tool substrate, which may accelerate the tool wear.