ZrO_2增韧Al_2O_3陶瓷的力学性能和增韧机制

对通过热压烧结法制备的3种陶瓷99.5vol%Al2O3(AD995)、ZrO2(15vol%)/Al2O3和ZrO2(25vol%)/Al2O3的力学性能和增韧机制进行了实验和理论研究。基于复合材料细观力学理论并考虑ZrO2的相变特性,建立了描述ZrO2/Al2O3陶瓷力学性能的本构模型。结果表明:ZrO2的加入细化了基体Al2O3晶粒,ZrO2/Al2O3陶瓷的致密性得到提高;3种陶瓷试件的破坏呈现小变形到脆性破坏的特点,压缩加载下试件应力-应变曲线近似为线性关系;AD995陶瓷的断裂韧性为5.65 MPa·m1/2,ZrO2(25vol%)/Al2O3陶瓷的断裂韧性为8.42 MPa·m1/2,提高了近50%;随ZrO2增韧相含量的增加,ZrO2/Al2O3陶瓷的弹性模量降低而断裂韧性增加,这一变化趋势与实验结果有良好的一致性。

Mechanical properties and toughening mechanisms of ZrO2 toughened Al2O3 ceramics

Mechanical properties and toughening mechanisms of three ceramics, 99.5vol% Al₂O₃ (AD995) ceramic, ZrO₂(15vol%)/Al₂O₃ ceramic and ZrO₂(25vol%)/Al₂O₃ ceramic prepared by hot pressing sintering were investigated by experimental and theoretical research. Based on the micro-mechanics theory of composites, a micromechanical constitution model was developed to describe mechanical properties of ZrO₂/Al₂O₃ considering phase transformation of ZrO₂. The results show that the grain size of Al₂O₃ matrix decreases and densification is improved with addition of ZrO₂. The failure of three ceramic specimens show characteristic of small deformation to brittle failure. The compression stress-strain curves show an approximately linear relationship. The fracture toughness of AD995 ceramic is 5.65 MPa·m^1/2, while ZrO₂(25vol%)/Al₂O₃ is 8.42 MPa·m^1/2, approximately 50% improvement.With toughening phase ZrO₂ content increasing, elastic modulus of ZrO₂/Al₂O₃ decreases and fracture toughness increases, which are consistent with experimental results.