Oxidation-induced crack healing in Zr2Al4C5 ceramic

The crack-healing behavior of Zr2Al4C5 was investigated by oxidizing the pre-cracked sample. A Vickers indentation (∼80 μm in size) was introduced and the crack was healed under different temperature. Cracks could heal completely in air above 1000 °C, with oxidation products consisting primarily of t-ZrO2 and α-Al2O3. The bending strength of crack-healed specimen (188–283 MPa) is higher than that of cracked samples (182 MPa), but all of them are lower than the strength of as-sintered and polished specimens (420 MPa). This composite has self crack-healing ability at temperatures ranging from 800 to 1200 °C, with 1000 °C being the optimum healing temperature.