Journal of Inorganic Materials, Volume. 38, Issue 11, 1265(2023)
To study the mechanical properties at high temperature of pre-stressed ceramics which were prepared by using higher expansion coefficient materials as coating and lower expansion coefficient materials as substrate, zirconia and alumina were chosen as the coating and the substrate, respectively, to fabricate ZrO2-Al2O3 (marked as ZcAs) pre-stressed ceramics with sandwich structure. Meanwhile, Al2O3-ZrO2 pre-stressed ceramics (marked as AcZs, which has the similar section ratio between substrate and coating to ZcAs), ZrO2 ceramics and Al2O3 ceramics were set as the reference samples. Combining the results of bending strength at different temperatures with the results of Vickers indentation, the existence form of residual stress and its influence on crack propagation behavior were clarified as well as the temperature dependence of residual stress. Results show that the residual tensile stress exists in the surface layer of ZcAs, while the compressive stress exists in the substrate. On the contrary, the compressive stress exists in the surface layer of AcZs and tensile stress exists in the substrate. Due to tensile stress promoting while compressive stress inhibiting crack growth, flexural strength of ZcAs is 13.2% lower than that of Al2O3, and AcZs possesses strength 25.0% higher than that of ZrO2 at room temperature. In addition, both tensile stress and compressive stress are decreased with the increase of temperature, which is mainly attributed to the relaxation of pre-stress caused by high temperature.
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Haiyan LI, Fenghua KUANG, Haolong WU, Xiaogen LIU, Yiwang BAO, Detian WAN.
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Received: May. 5, 2023
Accepted: --
Published Online: Mar. 6, 2024
The Author Email: BAO Yiwang (ywbao@ctc.ac.cn), WAN Detian (dtwan@ctc.ac.cn)