研究了不同SiC晶须音量的Al2O3/TiB2/SiCw陶瓷刀具材料的断裂韧性随温度的变化规律。结果表明：Al2O3/TiB2/SiCw陶瓷材料的K1e在1000℃内随温度的升高而增大；晶须含量越高，K1e增幅越大。通过计算分析表明：随温度的升高断裂时拔出的晶须大大增多。当晶须体积含量（下同）为20%时，Al2O3/TiB2/SiCw陶瓷在室温时只有长径比小于2.87的晶须在断裂时才有可能产生拔出，而在900℃时长径比小于10的晶须都能产生拔出。在同样温度条件下，晶须含量越高所能产生拔出的晶须增多。当晶须含量为40%时（晶须长径比为10），在温度大于620℃时能产生晶须的拔出，而当晶须含量为18%时, 只有温度大于940℃才能产生拔出。晶须含量越高其高温增韧效果越强。

A new ceramic cutting fool material has been developed by means of silicon carbide whisker (SiCw) reinforcement and silicon carbide particle (SiCp) dispersion. The material has the advantage of high bending strength and fracture tougbness. Compared with the mechanical properties of Al2O3(A), Al2O3/SiCp(AP), Al2O3/SiCw(AW), Al2O3/SiCw(JX-1) and Al2O3/SiCp/SiCw(JX-2), it confirms that JX-2 composite has obvious additive effect of both reinforcing and toughening. The reinforcing and toughening mechanisms of JX-2 composite have been studied based on the analysis of thermal-expansion mismatch and the observation of microstructure, Synergistic effects of toughening and strengthening for JX-2 have been researched systematically.

A review of advanced ceramic tool material, including its development, app]ication and the new trend in research, is offered in this article. As one of the most important tool materials to be used in the next century, advanced ceramic material has great potential and broad prospects. The major subject in the future study is the development of new type of ceramic tool material and finding ways to increase its strength and toughness as well as its reliability. The imperative task at present is how to popularise ceramic tools and how to use them more efficiently and reasonably.

A new criterion of fracture mechanics-stochastic characteristics for cemented carbide tool fracture in consideration of cutting temperature effect is proposed in the paper. Experimental results show that the theoretical tool life by fracture obtained from the criterion proposed for tool fracture presents a good agreement with the experimental one.

A new criterion of fracture mechanics-stochastic characteristics for ceramic tool fracture based on the analysis of its fracture features in intermittent turning, is proposed in the paper. A series of experiments on mechanical performance for ceramic tool as well as cutting tests on tool life by fracture have been done. The stresses in tool tip are analysed by finite element method Allof these show that the modified distribution function of theoretical tool life by fracture derived from the mentioned new criterion presents a good agreement with the experimental results, SEM analysis on the tool fracture faces indicates the late fracture of ceramic tool appears in fatigue features