Finite element design and fabrication of Al2O3/TiC/CaF2 gradient self-lubricating ceramic tool material

Abstract

Based on the idea of a functionally gradient material, the gradient self-lubricating ceramic tools were designed to solve the problem that the antifriction property and wear resistance of self-lubricating ceramic tools cannot be simultaneously considered. Physical, composition distribution, and micromechanical models were established. The finite element method was used to analyze the residual thermal stress of symmetrically distributed gradient ceramic tools with different compositional distribution exponent (n) values. When n=1.8, the stress gradient was small and the lowest value of the maximum Von Mises stress was obtained. An Al2O3/TiC/CaF2 gradient self-lubricating ceramic tool material with good mechanical properties was then fabricated by hot-pressing technique according to the optimum design results. Residual stresses were calculated by indentation crack method. Results showed that in the gradient self-lubricating ceramic tool material, compressive stresses were formed in the surface layers, whereas tensile stresses were formed in the middle layer, which were consistent with FEM-calculated findings.