Analysis of tool wear of TiAlN coated tool, machined surface morphology and chip during titanium alloy milling

TiAlN coated tools, known for their excellent resistance to high-temperature and low friction coefficient, are widely used in the processing Ti-6Al-4V alloy. This study conducted a systematic analysis of the wear phenomenon of TiAlN coated tools during the dry milling of Ti-6Al-4V alloy. Based on molecular dynamics (MD) and experiments, the interaction mechanism between diffusion wear and other wear mechanisms was investigated. The study further investigated the influence of tool wear on the machined surface morphology and chips. The results revealed tool diffusion wear was identified as the outward diffusion of Co and W elements. Ti element diffusion was more responsive to changes in temperature and pressure. During the tool wear process, a synergistic effect was observed between diffusion wear and adhesion wear. The combined impact of diffusion wear and oxidation wear weakened the tool's strength. The main forms of defects on the machined surface were grooves, pits, surface tears, and adhesion. As tool wear increased, the aggravation of grooves was the main reason for the reduction of roughness of machined surface. Additionally, as tool wear increased, the chip transitioned from a conical spiral chip to an arc-shaped chip, and an increase in the sawtooth degree of chips.