Influence of graphite on the low-frequency fatigue behavior of zirconium diboride ceramics

作者：Wang, Anzhe; Wang, Shuai; Zhou, Peng^*; Zhang, Zhen; Dai, Yajie; Zhang, Dongyang^*

来源：Journal of the European Ceramic Society, 2022, 42(6): 2630-2639.

DOI：10.1016/j.jeurceramsoc.2022.01.055

• Ceramic
• Static fatigue
• Cyclic fatigue
• Stress intensity factor
• Fractography

The fatigue behavior of a ZrB2-based ceramic containing SiC and graphite was compared to a ZrB2-SiC reference material based on bending testing, quantitative calculations as well as crack growth and fracture characterization. The addition of graphite flake makes ZrB2-SiC-Graphite ceramics exhibit fatigue failure behavior at very high stress level (93% of the characteristic strength, sigma(0)), owing to the increased K-Ic promoted by crack deflection, bridging, bifurcation and pull-out of graphite, while the fatigue behavior of ZrB2-SiC appears when the maximum stress is below similar to 86%sigma 0. However, both the slow crack growth exponents of the graphite containing ceramic, n and nc values, which reflect the fatigue resistance in static and cyclic fatigue conditions, respectively, are only 1/4 as compared to the reference graphite-free ceramic. This may be due to the weak boride/graphite interfaces, which lead to the decrease of the initial critical stress intensity factor (Kc-initial) value from 2.6 to 2.0 MPa m(1/2).

• 单位
  Sun Yat-sen University