Self‐Crack‐Healing Behavior of Mullite/SiC Particle/SiC Whisker Multi‐Composites and Potential Use for Ceramic Springs

To improve fracture toughness and encourage excellent self‐crack‐healing ability, mullite/SiC particle/SiC whisker multi‐composites and mullite/SiC whisker composites were hot pressed. The crack‐healing abilities and mechanical properties of these sintered composites were investigated. Based on the obtained results, the usefulness of the mullite composite as a material for springs was discussed. The part of mullite/15 vol% SiC whisker/SiC 10 vol% particle containing healed cracks retained high reliability over the whole measured temperature range. When the crack‐healing ability was endowed by SiC whiskers alone, the parts containing the healed pre‐cracks were found to have a heat‐resistance limit temperature. Mullite/15 vol% SiC whisker/10 vol% SiC particle multi‐composite had the best potential as a material for springs used at high temperatures, because it had an adequate crack‐healing ability as well as shear deformation ability almost two times stronger than that of monolithic mullite.