SiC/Ti(C,N)/Al2O3陶瓷复合材料的抗热震性能设计及其切削应用

抗热震性能是结构陶瓷材料的重要性能之一．以抗热震断裂参数表征材料的抗热震性能，采用理论与实验相结合的方法，建立了基于抗热震性能的陶瓷复合材料的组分设计模型，并采用计算机辅助优化设计技术求得材料的最优组分．结果表明：当Ti（C，N）和SiC的体积含量分别为10．4％和27．1％时，该材料具有最高的抗热震性能，比纯氧化铝陶瓷提高约55％．在此基础上，利用热压技术制得一种SiC／Ti（C，N）／Al2O3复合陶瓷材料．将该材料制成切削刀具，并在切削实验中通过设计切削条件使得刀具主要承受热载荷和热应力的作用，从而发生热）中击破损．实验发现，SiC／Ti（C，N）／Al2O3复合陶瓷刀具切削淬火钢时的抗热）中击破损性能较纯Al2O3陶瓷提高约62-68％，与抗热震性能设计的理论预测基本吻合．这表明，该设计方法是可行的．

Design of Thermal Shock Resistance of SiC/Ti(C,N)/Al2O3 Ceramic Composite and its Machining Application

Thermal shock resistance is one of the primary properties for structural ceramic materials.The thermal stress fracture resistance factor R is used to characterize the thermal shock resistance of the ceramic material.By means of the combination of both theoretical and experimental methods,an optimum model for the compositional design of the ceramic composite is built based on thermal shock resistance.The computer aided optimum design technique ia adopted to get the optimum material compositions.Results show that the developed SiC/Ti(C,N)/Al_2O_3 ceramic material can be expected to achieve the highest thermal shock resistance when the volume fraction of Ti(C,N) and SiC is about 10.4% and 27.1%,respectively.Then,a kind of SiC/Ti(C,N)/Al_2O_3 ceramic with optimum compositions is prepared for use as cutting tools.In cutting test,cutting conditions are purposely designed to make the tool insert mainly undertake the action of thermal load and thermal stress.It indicates that thermal fracture resistance of the SiC/Ti(C,N)/Al_2O_3 ceramic material is approximately 62-68% higher than that of the pure alumina ceramic when machining the hardened carbon steel,which coincides well with the theoretical prediction from the optimum model.It suggests that the method used here is feasible for the development of ceramic materials with designed thermal shock resistance.