The properties of YA-TZP depend on its microstructures. Optimal combination of mechanical properties with
σb =940~1010 MPa and
K1c=10.9 MPa√
m was obtained as the critical grain size~0,7μm. No strength degradation after aging at 250℃ for 50h. The morphology of different phases in ZrO
2, the microcracks and particles of secondary phase wereinvestigated and dislocation networks and lines were found under TEM. Pre-liminary tests show good prospect on application for wire drawing dies.