Effects of material microstructure and surface microscopic geometry on the performance of ceramic cutting tools in intermittent turning

Abstract

The present work was performed to reveal the integrated effects of material microstructure and surface microscopic geometry on the performance of Al2O3-based composite ceramic cutting tools in intermittent turning. Influences of material microstructure on the initial elastic modulus and material damage of ceramic cutting tools were evaluated on the basis of the established microstructure models and damage mechanics. The effects induced by tool surface microscopic geometry on cutting forces and tool temperatures were revealed based on finite element simulation. Taking the cutting condition into account, a new indicator was used to reflect the integrated effects of material microstructure and surface microscopic geometry on tool performance. A theoretical method was proposed to acquire the optimal combination of tool material microstructure and tool surface microscopic geometry in terms of too life. When material porosity increased from 0.5% to 2.5%, elastic modulus and tool damage decreased and increased, respectively. Compared to ceramic tool material (A) reinforced only by micro (W, Ti)C particles, the variation of material porosity had less effects on the damage within the tool material (B) which contained both micro (W, Ti)C and nano Al2O3 particles. Designing micro-texture pattern (pattern d) on the tool rake face with both the solid-like and liquid-like properties of the chip considered was most efficient for the reduction of cutting forces and tool temperatures. The optimum combination of tool material microstructure and tool surface microscopic geometry can be achieved by using ceramic tool material B and micro-texture pattern d. The experimental tool lives demonstrated the correctness of the tool performance indicator and the theoretical method for acquiring the optimum combination of tool material microstructure and tool surface microscopic geometry.