颗粒补强锆英石复相陶瓷的力学性能、残余应力和增韧行为研究

Mechanical Properties, Residual Stress and Toughening Behavior of Particulate Reinforced Zircon Matrix Composites

本文采用X射线衍射方法测定了颗粒补强锆英石基复相陶瓷基体中的残余应力，通过力学性能测试，结合显微结构观察；讨论了残余应力与补强颗粒增韧行为之间的关系．结果表明：在基体热膨胀系数小于补强颗粒的情况下，适当增大补强颗粒与基体间热膨胀失配，能够提高复相陶瓷的增韧效果．其增韧机制主要为；补强颗粒所引起的裂纹偏转和分支．利用残余应力场增韧模型计算得到的复相陶瓷断裂韧性增量与实际值能够较好的吻合．

The residual stress in the particulate reinforced zircon matrix composites was characterizedby X-ray diffraction method. The relationship between the residual stress and toughening behaviorwas discussed on the basis of mechanical properties determination and microstructural observation.The results indicated that a bigger mismatch in the coefficients of thermal expansion of reinforcingparticle and matrix leads to a better toughening effect when the thermal expansion coefficientof particle (αp) is higher than that of matrix (αm). It was suggested that the main tougheningmechanisms were the crack deflection and branching, which were attributed to the existence ofresidual stress. The increments of fracture toughness of composites calculated by residual stressfield theory were in good agreement with the experiment values.