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

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.

Better and more capable tool materials allow machine tools to cut at increasingly higher speeds and feeds. Inrecent decades, high speed machining has received an important interest as a technological solution for high productivityto increase economic efficiency in manufacturing. The recent developments of cutting tool materials in high speed ma-chining are reviewed. The appropriate applications of the high speed machining technology are presented. It can concludethat the optimal matching of meehardcal, physical, end chemical properties between teol and workpieee materials is veryimportant in high speed machining. The researeh is very grit beneficial to the design and the selection of re431 materials hihigh speed machining.

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.

Though there are already a varlety of models for comples, they are not so convenientneeded in practice. A hlerchical model and the principle of decomposition and reconstitution for complex surfaceshave beem proposed, which have the potential to enhance the support of automated design systems on creative work intelligently. Then the progress made is discused involving the application of the new principle in the following threeareas; conugation sudace calculation, tool path generation in numercally controlled machining, and maching proccessinnovation By re-recognition.