Machinability Investigation in High Speed Turning of Powder Metallurgy Nickel-based Superalloy with Sialon Ceramic Inserts

An experimental investigation was carried out to understand the behavior of a powder metallurgy nickel-based superalloy when machined with sialon ceramic insert tools. Turning experiments were carried out at different cutting speeds and feed rates while depth of cut was kept constant. Cutting tool performance was evaluated with respect to temperature and cutting forces generated during turning, and tool wear. The sialon ceramic cutting tool showed high performance when increasing cutting speed, the machining experiments showed that sialon ceramic tools performed better at cutting speed up to 80 m/min. Abrasion and adhesion was the dominant wear mechanisms. Chipping on the tool rake and flank faces, as well as catastrophic failure under thermal shock and mechanical loading, was also observed in experiments. As cutting temperature was very high when turning powder metallurgy nickel-based superalloy, good high-temperature strength and thermal shock resistance were indispensable to the cutting tools for machinging this kind of material.