Cutting performance and coated tool wear mechanisms in laser-assisted milling K24 nickel-based superalloy

Abstract

Laser-assisted machining (LAM) offers the ability to machine superalloys more efficiently and economically by providing the local heating of the workpiece prior to material removed by traditional cutting tool. The effectiveness of LAM was studied by measuring the cutting forces, surface roughness, and tool wear under various material removal temperatures (Tmr). It is demonstrated by an appropriate 30–70 % decrease in cutting force, an obvious reduction in the surface roughness, and an appropriate 46 % increase in coated tool life over conventional machining (CM). Machining experiments are then carried out to evaluate the wear behavior of different commercially available coated tools (TiCN, TiAlN, Ti(CN)/Al2O3/TiN). These coatings were selected since they have the capability to withstand the temperatures experienced in LAM. The results of laser-assisted milling experiments indicate that abrasive and adhesive wear were the dominant wear mechanisms, controlling the deterioration of the carbide tools. The TiAlN-coated tools exhibited the highest wear resistance at normal cutting speeds of 30 m/min. The triple layer CVD coated tool failure mode was non-uniform flank wear due to the adhesion and depth-of-cut notching. TiCN performed poorly due to their inferior adhesion characteristics with the base material. The main failure mode for TiCN was non-uniform flank wear and chipping, and also, a significant notch was observed. Sub-surface quality has been evaluated by observing the microstructure of cross sections and measuring the micro-hardness.