WEAR RATES AND WEAR MECHANISMS OF ALUMINA-BASED TOOLS CUTTING STEEL AT A LOW CUTTING SPEED

Three ceramic insert materials, zirconia-toughened alumina (Al2O3-7vol %ZrO2), mixed-based alumina (Al2O3-TiN-TiC-ZrO2) and alumina reinforce d with SiC whiskers (Al2O3-SiCw), were used to cut AISI 1040 steel at 3.9 m s(-1). In addition, a traditional grade P10 insert (WC-TiC-Co) w as tested, The lifetimes, according to KT/KM and VBB criteria, were de termined using a profilometer and by image processing. The worn zones were observed with scanning electron microscopy techniques. Adhesion a nd plastic deformation were dominant wear mechanisms in zirconia-tough ened alumina, mixed-based alumina and sintered carbide P10, both in th e craters and in the cutting edges. As well as adhesion in alumina rei nforced with SiC whiskers, a chipping wear mechanism was observed.