Wear mechanisms of coated carbide tools during high-speed face milling of Ti2AlNb intermetallic alloys

Ti2AlNb intermetallic alloy is currently the most promising lightweight high-temperature resistant material in the aerospace industry, owing to its high specific strength, favourable room temperature plasticity, outstanding temperature strength, and creep resistance. High speed cutting technology is characterized by low cutting force, minimal thermal deformation, high material machining efficiency and precision, which is widely used in machining TiAl intermetallic alloys and associated key components to ensure superior machined surface quality and dimensional accuracy. However, there are serious tool wear during high speed cutting of Ti2AlNb intermetallic alloys because of its high specific strength and temperature strength, and the tool wear mechanism is unknown. In this paper, the high-speed face milling trials of Ti2AlNb intermetallic alloys are performed to investigate tool wear evolutions and wear mechanisms. More specifically, tool wear morphologies, tool tip breakage, machined surface roughness, and cutting forces are investigated in detail. Results indicate that high-speed face milling results in severe tool wears, leading to a rapid increase in cutting forces and machined surface roughness during the severe wear stages. The tool's service life is limited to 228 s due to tool tip breakage resulted from coating delamination, cracking, and mechanical impact. Tool wear morphologies encompass tool rake face and flank face wear, exhibiting typical characteristics of coating delamination and microchipping. Adhesive wear and oxidation wear are the primary mechanisms of tool wear, occurring on both the rake face and flank face. The experimental results can provide a reference for high speed machining of TiAl material and promote the application of the material.