Development and erosion wear of SIC/(W,Ti)C functionally gradient ceramic AJM nozzle

The idea of functionally gradient material (FGM) theory was used to the design of ceramic nozzle. The purpose was to reduce the stresses at the entrance and exit area of the nozzle during abrasive jet machining (AJM) processes. The SiC(WTi)C homogeneous and FGM nozzles were produced by hot pressing. The erosion wear of these nozzles caused by abrasive particle impact was investigated. Results showed that the hardness of the nozzle material played an important role in the erosion wear of the nozzles. The Vickers hardness of 45Vol.%SiC layer with high hardness exhibited lower erosion rates, and the Vickers hardness of 25Vol.%SiC layer with relative low hardness showed higher erosion rates under the same test conditions. The entrance and exit area of the SiC (W,Ti)C homogeneous nozzle we re worn badly owing to the wear mechanisms exhibited a brittle fracture induced by removal process. The middle area of the SiC (W,Ti)C homogeneous nozzle showed mainly plowing and microcutting. The entrance area of the SiC (W,Ti)C FGM nozzle exhibited a fracture induced by removal process. The exit area of the SiC (W,Ti)C FGM nozzle indicated that brittle fracture took place. The primary wear mechanisms of the middle area of the SiC (W,Ti)C FGM nozzle is plowing and microcutting by the abrasive particles.