Study on the effect of sample shapes on the thermal shock behavior of ZrB2‐SiC‐Graphite sharp leading edge

Abstract

Abstract Reliable evaluation of the thermal shock behavior of sharp leading edges (SLEs) was hampered by a lack of available experimental method in past decades. Herein, a novel water spraying method was utilized to investigate the shape effect of ZrB2‐SiC‐Graphite SLEs during thermal shock. Experimental results indicated that the critical failure temperature of ZrB2‐SiC‐Graphite SLEs was most sensitive to the wedge angle, which could lead to a dramatic attenuation by about 35% from 12° to 9°, and was relatively little affected by the tip radius of curvature and the thickness. Simulation results further revealed that the decay of critical failure temperature was mainly due to the significant stress concentration caused by the reduction of wedge angle. Scanning electron microscopy observation proved that cracks tend to bypass graphite flakes due to their weak interfacial bonding, while branching always occurred when encountering hard phases or inclusions.

Keywords

• fracture
• sharp leading edges
• thermal shock
• ultra‐high‐temperature ceramic