Transformation toughening in zirconium tantalum ceramics

Toughness enhancement of zirconium tantalum ceramics is conducive to the new generation of thermal barrier coatings (TBCs). The phase transformation toughening mechanism of zirconium tantalum ceramics has been explored through the Vickers indentation of YTaO4 ceramic block, the phase transformation region is found near the indentation and the microcrack tip. The increased energy of stable phase Delta EM-M '>0, and the volume expanded Delta V approximate to 1.9%, so, the phase transformation is a process of energy absorption. The additional stress alpha(a) restraining the crack propagation was generated in the shielding area at the crack tip. In addition, combined with the toughening of ferroelastic domains switch, the traditional microcrack toughening, and crack propagation toughening, we summarized the toughening mechanism of YTaO4 ceramics with the increasing external load, which is followed by ferroelastic toughening, phase transformation, microcrack, and crack propagation. For the perspective of toughening, we found that Z(4+) doping in YTaO4 ceramics could broaden the phase transformation range in phase transformation toughening, significantly improve the toughness and reduce the generation of cracks in microcrack toughening and crack propagation toughening. Therefore, toughening mechanism of zirconium tantalum ceramics has important guiding significance for the service of TBCs.

Automated summary

This study explores the phase transformation toughening mechanism of zirconium tantalum ceramics and finds that the phase transformation region is near the indentation and microcrack tip. It also summarizes the toughening mechanisms of YTaO4 ceramics and the effect of Z(4+) doping on toughening. These findings have important guiding significance for the use of TBCs.