Development Of Layered Ceramic Composite Cutting Tools And Study On Their Cutting Performance

Ceramic cutting tools are used more widely in industrial production, because they have high hardness, high melting point, good thermal stability, good wear resistance, and many other advantages. Nevertheless, their widespread use is limited by their disadvantage of brittleness. In the article, layered ceramic composite cutting tools were developed. And the cutting performance, wear properties and mechanisms were detailed studied.The layered models were established and the distributions of the residual stresses in the layered ceramic composites were studied by the means of finite element method. The influences of the number of layers and thickness ratio on the surface residual stresses were studied. The results indicate that the layer of surface formed residual compressive stress and the layer of inner formed residual tensile stress. The value of residual compressive stress on the surface increased with the thickness ratio or the number of layers rising. The surface residual compressive stress of A3-8 layered model was -287 MPa. A uniform residual compressive stress zone formed near the center.Layered ceramic materials with different layers or thickness ratios were prepared. The mechanical properties of layered ceramic materials were measured. And the microstructure of the layered ceramic materials was studied. The researches indicate that the fracture toughness and the hardness of the layered ceramic materials increased with the thickness ratio or the number of layers rising. The fracture toughness of the surface for layered ceramic materials with 7 layers was 10.05 MPa/m^1/2, and the hardness was 22 GPa. The mechanical properties of layered ceramic materials would be better if the surface was thinner. The residual stress effected the growth of the surface crack in different direction.Wear properties and mechanisms of the layered ceramic cutting tools were compared with the single-layer cutting tool when cutting 45# hardened steel and cast iron QT420-10. The surface residual compressive stress affected the wear properties. The results indicated that the layered ceramic composite cutting tools exhibited higher erosion wear resistance over the single-layer ceramic cutting tool. Five-layer ceramic cutting tool showed good wear resistance when cutting cast iron QT420-10 at higher speed.