Fabrication and cutting performance of an Al<SUB align=right>2O<SUB align=right>3-(W, Ti)C functionally gradient ceramic tools

Abstract

According to the design rules for Functionally Gradient Materials (FGM) with high thermal shock resistance proposed in the previous work of the author, an Al2O3-(W, Ti)C FGM ceramic tool material with symmetrically laminated structure was fabricated by using hot-pressing technique. The cutting performance, failure modes and mechanisms of the FGM ceramic tool were investigated via intermittent cutting experiments in comparison with those of a common homogeneous Al2O3-(W, Ti)C ceramic tool. The results revealed an improved tool live of the FGM tool over that of the homogeneous ceramic tool. The FGM tool exhibited similar chipping characteristics and failure modes to that of the homogeneous ceramic tools at a lower cutting speed, but different failure modes from that of the homogeneous ceramic tool at higher cutting speeds. The failure of the homogeneous ceramic tool at higher cutting speeds was mainly caused by plastic deformation and thermal shock, whereas the failure mechanisms of the FGM tool were mainly the mechanically induced wear and mechanical fatigue in virtue of the improved thermal shock resistance.