Wear and Tribological Performance of Different Ceramic Tools in Dry High Speed Machining of Ni-Co-Cr Precipitation Hardenable Aerospace Superalloy

Tool wear is an important machinability criterion. To reduce total machining costs, this study demonstrates the wear and tribological performance of four ceramic tools in dry high-speed turning of Ni-Co-Cr precipitation hardenable superalloy (Inconel 100). Wear of the tool materials and the structural and phase transformations at the tool–chip interface were investigated. Results obtained reveal that SiAlON ceramic outperformed other ceramic tool materials at different cutting speeds due to the formation of a large amount of mullite tribofilms on the tool face, which serve as a thermal barrier layer. Alumina ceramic with the addition of ZrO₂ can be recommended for machining Inconel 100 at speeds above 150 m/min due to its ability to form thermal barrier ZrO₂ tribofilms, which decrease the coefficient of friction at the tool–chip interface. Mixed alumina and an alumina matrix reinforced with SiC_w were found to be unsuitable for machining age-hardened Inconel 100 superalloy.