关键词: 残余应力, 冲蚀磨损, 陶瓷喷嘴, 梯度功能材料, 应力分析

Abstract: The stress states of the nozzle in abrasive jet machining (AJM) process are analyzed. Results show that the maximum stress appears in entrance area of the nozzle and minimum stress in middle area, while the stress of exit area is lower than entrance area and higher than middle area. Blasting results reveal that the nozzle entry region always suffers form severe abrasive impact, and generates large tensile stress, which leads to an increased erosion wear at the nozzle entry area. The idea of functionally gradient material (FGM) theory is used to design ceramic nozzle. The design of composition distribution of the gradient ceramic nozzle is carried out with the aim of partial relaxation of the stress resulting from external loadings by residual thermal stress. Based on the design results, a SiC/(W,Ti)C gradient ceramic nozzle is produced. The erosion behavior of the SiC/(W,Ti)C gradient ceramic nozzle is investigated in comparison with the common ceramic nozzles. Results show that the SiC/(W,Ti)C gradient ceramic nozzles exhibit an apparent increase in erosion wear resistance over the common ceramic nozzles under the same test conditions.

Key words: Function gradient material, Ceramic nozzle, Erosion wear, Residual stress, Stress analysis