In this paper, B4C/(W,Ti)C ceramic composites with different content of solid-solution (W,Ti)C were produced by hot pressing. The effect of (W,Ti)C content on the microstructure and mechanical properties of B4C/(W,Ti)C ceramic composites has been studied. Results showed that a chemical reaction took place for this system during hot pressing, and resulted in a B4C/TiB2/W2B5 composite with high density and improved mechanical properties compared to monolithic B4C ceramic. Densification rates of the B4C-based ceramic composites were found to be affected by addition of (W,Ti)C. Increasing (W,Ti)C content led to an increase of the densification rates of the composites. The sintering temperature was lowered from 2150℃ for monolithic B4C to 1850℃ for the B4C/(W,Ti)C composites. The fracture toughness and flexural strength continuously increased with increasing (W,Ti)C content up to 50wt.%, while the hardness decreased with increasing (W,Ti)C content.

In ultrasonic machining (USM), the material is removed primarily by repeated impact of the abrasive particles, and the material removal rate (MRR) and surface integrity are influenced by various factors including the material parameters of the workpiece materials. In this study, effect of the properties and microstructure of the workpiece materials on the MRR in ultrasonic machining of alumina-based ceramic composites was investigated. The distributions of strength of the ultrasonic machined specimens were used to evaluate the surface integrity. Results showed that fracture toughness of the ceramic composite played an important role with respect to MRR. In USM of whisker-reinforced alumina composites, the MRR depended on the whisker orientation. Studies of strength distributions of alumina-based ceramic composites machined by USMdemonstrated that the flexural strength varied narrowly from the mean value, and the composites with high fracture toughness showed higher Weibull modulus.

Good surface integrity is frequently required for structural ceramic components, since the lifetime of a ceramic component is in most cases determined by its surface features. In this study, the surface integrity of electro-discharge machined, ultrasonic machined, and diamond saw cut ceramic composites has been investigated and compared. The surface roughness, hardness, and topography of the machined surface were examined. Flexural strength and its distributions were used to evaluate the e

Sand blasting nozzle is the most critical part in the sand blasting equipment. Ceramics being with high wear resistance have great potentials as the sand blasting nozzle materials. In this paper, monolithic B4C andAl2O3/(W,Ti)C ceramic composite were developed to be used as nozzle materials. The wear behavior of nozzles made from these ceramic materials was compared by determining the cumulative mass loss and the erosion rates. Effect of the factors that influence the nozzle wear was investigated. Results showed that the hardness of the nozzles plays an important role with respect to its erosion wear in sand blasting processes. The monolithic B4C nozzles being with high hardness exhibited lower erosion rates, while the Al2O3/(W,Ti)C nozzles with relative low hardness showed higher erosion rates under the same test conditions. Studies of the worn surface of the ceramic nozzles demonstrated that monolithic B4C nozzles exhibited a brittle fracture induced removal process, while Al2O3/(W,Ti)C nozzles showed mainly a plowing type of material removal mode.

Good surface integrity is frequently required of struc-tural ceramic components, since the lifetime of a ceramic component is, in most cases, determined by its surface features. In this study, two mechanical surface treatments, i.e. ultrasonic and abrasive blasting sur-face finishing, have been introduced to the surface of electrodischarge machined ceramic composites to improve their surface integrity. T he surface roughness, hardness, and topography of the ceramic composites were examined after electrodischarge machining (EDM) and surface treatment. T he eVect of surface integrity on the strength and its distribution was investigated. Results show that ultrasonic and abrasive blasting surface finishing can produce an improvement in both flexural strength and Weibull modulus, and are two eVective procedures to improve the surface integrity of the EDM ceramic composites.