Mechanical and tribological properties of SiC whisker-reinforced SiC composites via oscillatory pressure sintering

摘要

SiC whisker (SiCw)-reinforced SiC composites were prepared by an oscillatory pressure sintering (OPS) process, and the effects of SiCw content on the microstructure and mechanical and tribological properties of such composites were investigated. The addition of SiCw could promote the formation of long columnar alpha-SiC, and the aspect ratio of alpha-SiC grains first increased and then decreased with the increase of SiCw content. When the SiCw content was 5.42 wt%, the relative density of the SiC-SiCw composite reached up to 99.45%. The SiC-5.42 wt% SiCw composite possessed the highest Vickers hardness, fracture toughness, and flexural strength of 30.68 GPa, 6.66 MPa center dot m(1/2), and 733 MPa, respectively. In addition, the SiC-5.42 wt% SiCw composite exhibited the excellent wear resistance when rubbed with GCr15 steel balls, with a friction coefficient of .76 and a wear rate of 4.12 x 10(-7) mm(3)center dot N-1 center dot m(-1). This could be ascribed to the improved mechanical properties of SiC-SiCw composites, which enhanced the ability to resist peeling and micro-cutting, thereby enhancing the tribological properties of the composites.