In situ measurements of the high-temperature mechanical properties of ZrO2-doped YTaO4 ceramic by three-point bending combined with a digital image correlation method

Abstract

ZrO2-doped YTaO4 ceramics with different ZrO2 contents (Y1-xTa1-xZr2xO4 ceramics, 2x = 0, 0.1, 0.15, 0.2) are prepared by a solid-state reaction method. The high-temperature mechanical properties are determined by an in situ high-temperature three-point bending combined with the digital image correlation (DIC) method. The results show that when the temperature rises from 25 °C to 800 °C, the temperature dependence of the elastic modulus, fracture toughness and fracture strength with a ZrO2 doping content of 10% mol is relatively small. The elastic modulus, fracture toughness and fracture strength decrease from 105.4 GPa to 96.1 GPa, from 2.6 MPa m1/2 to 2.3 MPa m1/2 and from 73.8 MPa to 64.8 MPa, respectively. Transgranular fracture is the main fracture mode. When the crack propagates through the twin band, a phase transformation and a typical domain change occur. Furthermore, the crack propagating through the twin band at room temperature (25 °C) is more tortuous than that at 800 °C, and more energy needs to be consumed. This illustrates that the fracture toughness and fracture strength at room temperature (25 °C) are higher than those at high temperature.