陶瓷材料加工表面完整性及其对材料可靠性的影响

采用磨削-抛光加工、金刚石锯片切割加工、超声波加工和电火花线切割加工技术对Al2O3/TiC陶瓷材料进行加工.研究了各加工方法对陶瓷材料的加工表面完整性及其可靠性的影响.结果表明:加工方法对陶瓷材料加工表面完整性和可靠性有很大的影响.磨削-抛光加工的陶瓷试样表面粗糙度小,硬度高,抗弯强度及其可靠性最高.金刚石锯片切割加工和超声波加工次之;电火花加工陶瓷试样表面粗糙大,硬度低,抗弯强度及其可靠性最低.电火花加工陶瓷表面产生一硬度低且表面粗糙的约8μm厚的热影响层,加工表面含有大量的电火花腐蚀凹坑,随电流的增大,电火花加工陶瓷试样的抗弯强度及其可靠性降低.超声波加工陶瓷试样的表面完整性与磨料粒度有关,随磨料粒度的减小,陶瓷试样的抗弯强度及其可靠性增加.

Surface Integrity in Machining of Ceramic Composite and Its Effects on the Material Reliability

In this study,the surface integrity of Al 2O 3/TiC/Mo/Ni ceramic composites treated by grinding polishing,diamond saw cutting,ultrasonic machining,and electro discharge machining were investigated and compared.The surface roughness,hardness,and topography of the machined surface were examined.The flexural strength and its distribution were used to evaluate the effect of machining process on the surface integrity of the machined specimens.The results show that the machining process had an important effect on the surface integrity and reliability of the machined ceramics.Electro discharge machinig of ceramics created a heat affected surface layer with poor surface integrity,such as craters,and the variable surface damages on the electro discharge machined specimens resulted in low Weibull modulus.Within most machining conditions,the grinding polishing, diamond saw cutting and ultrasonic machined specimens behaved fairly consistently,and the flexural strength and Weibull modulus were higher than that of the electro discharge machined specimens.