Wear mechanisms of superhard cutting tools in machining of SiCp/Al composites

Abstract

Silicon carbide particle-reinforced aluminum matrix composite (SiC_p/Al) has been widely utilized in aerospace, rail transportation, and electronic components, owing to its high-performance properties such as high specific strength and stiffness, wear and fatigue resistance, good thermal stability, simple manufacturing process, and adjustable properties. However, its exceptional performance presents challenges to the material removal process as it leads to rapid tool wear, high and fluctuating cutting forces, affecting the processing efficiency and quality. The present study focuses on investigating the tool wear mechanism and failure process in the side milling of SiC_p/Al composite materials with polycrystalline cubic boron nitride (PCBN) and polycrystalline diamond (PCD) cutting tools. The results indicate that the wear characteristics of PCBN cutter flank face are blunt tip and rapid expansion of large wear area, whereas PCD cutter wear primarily manifests as minor chipping at the tip and gradual wear on the flank face. The cutting force of PCBN cutter is significantly higher than that of PCD cutter, exhibiting an average increase of 38.1 %. The PCBN cutter undergoes gradual and continuous material loss during the machining process, resulting in erosion and dulling of the cutting edge. In contrast, PCD cutter exhibits higher resistance to erosion and retains its sharp cutting edge even during normal wear conditions. The rake face of a PCBN cutter exhibits characteristics of build-up edge and scratches, with abrasive wear, adhesive wear, and possible diffusion wear. The tip of the PCD cutter displays a distinct serrated cutting edge, with minor scratches on the flank face and chip adhesion observed on the rake face. Here, the primary modes include adhesive wear, brittle fracture, and slight abrasive wear. These findings are expected to serve as valuable references for the efficient and high-quality machining of SiC_p/Al materials.