Wear patterns and mechanisms of SiAlON and SiC-whisker-reinforced Al2O3 ceramic tools in side milling Inconel 718

ABSTRACT In view of the difficult-to-machine characteristic of nickel-based superalloys, ceramic tools represent one of the ideal choices for cutting superalloys due to their excellent properties. The research conducted an experiment to evaluate the tool life and wear mechanisms of two self-developed ceramic tools and two commercially available ceramic tools (C1, C2, C3, C4) during side milling of Inconel 718 superalloy. The experimental results demonstrate that at the same cutting distance, the flank wear (VB) of the four ceramic tools shows the following relationship: C1 < C2 < C3 < C4. The dual-phase design of C1 incorporating α and β phases endows C1 with both good hardness and fracture toughness, whereas for C2 and C4, the difference in thermal expansion coefficients of their constituents and the oxidation of elements accelerate tool wear. The main wear patterns on the flank face are crater wear, flaking, and chipping. Notch wear is identified on C1, C2, and C3. In contrast, the primary failure pattern of C4 is cutting edge fragmentation at the tool corner. The main wear patterns on the rake face are chipping and flaking. During the machining process, adhesion of workpiece material to the tool substrate results in severe tool wear. The wear mechanisms of the four ceramic tools are adhesive wear, diffusion wear, oxidation wear and abrasive wear. This study provides theoretical support for the material design of ceramic tools.