Experimental Study on the Oxidation and Diffusion Behavior of Inconel 625 and Tool Materials

Oxidation and diffusion simulation experiments were conducted to choose the most suitable material for cutting the Inconel 625 superalloy. Three tool materials, WC/Co, coated carbide, and ceramic were used as tool materials in the oxidation simulation experiment. The three tool materials were heated for 30 min in a high-temperature furnace, and the high-temperature oxidation products were examined with scanning electron microscopy and X-ray diffraction (XRD). Tools were heated for 90 min in a vacuum tube furnace. The element diffusion behaviors of Inconel 625 and the tool materials were analysed with energy-dispersive X-ray spectroscopy and XRD. Some of the WC and Co in the WC/Co and coated carbide tool materials was oxidized to WO3, Co3O4, and CoWO4, and the oxidation reaction became more intense as the temperature increased. For the ceramic tool, only TiC was oxidized to TiO2, which indicates good oxidation resistance. In the diffusion couple experiments, the diffusion levels of the three tool materials increased with temperature, but the degree of influence differed. Diffusion of elements was hindered by the (Al, Ti) N coating of the coated carbide and effectively inhibited by the Al2O3 in the ceramic tool. In terms of oxidation and diffusion, the most suitable tool material for cutting Inconel 625 was the ceramic, followed by the coated carbide and then WC/Co.