Abstract
The application of the material design concept of functionally graded material to cemented carbide tools to realize good wear resistance in the surface region, good fracture toughness in the inside and compressive residual stress in the graded composition zone has been studied to improve their cutting performance. To develop the new material, the cutting condition of broken tools was investigated and their cutting temperature distribution was measured by a newly developed cutting temperature measuring method. Then computer aided engineering (CAE) analysis using the finite element method (FEM) for the measured cutting temperature distribution was performed to determine the generated thermal stress by the change in cutting temperature distribution. The new material was developed with the aim to introduce the compressive residual stress that exceeds the calculated thermal stress. Functionally graded cemented carbides with the intended compressive residual stress could be developed and this new material has higher wear resistance, breakage resistance and thermal crack resistance than those of conventional cermet with uniform composition.
