SiCw/ZTA(Y)陶瓷基复合材料力学性能的研究

Study on Mechanical Properties of SiCw/ZTA(Y) Ceramic Composites

研究了不同ＳｉＣ晶须（ＳｉＣｗ）含量对ＺＴＡ（Ｙ）陶瓷基复合材料力学性能的影响。实验结果表明，ＳｉＣ晶须能明显提高复合材料的抗弯强度和断裂韧性，晶须含量为２０ｖｏｌ％时，复合材料性能可达σｂｂ＝８３０ＭＰａ，ＫＩＣ＝９．８ＭＰａｍ１／２。但晶须含量过高时，复合材料的强度有下降趋势。分析认为，晶须通过拔出及促进裂纹偏转等机制对复合材料起到明显的补强作用。由于晶须与基体热膨胀系数的差异而引入基体中的张应力将使复合材料中存在较多的单斜相ＺｒＯ２。复合材料断裂过程中发生明显的ＺｒＯ２（ｔ）→ＺｒＯ２（ｍ）相变，且晶须的增加有利于断裂过程中的相变。复合材料中存在着晶须补强和相变增韧等双重强韧化机制。

The influence of sic whisker volume content on the mechnical properties of the SiCw/ZTA(Y)composites is studied.The results show that the flexure strength and fracture toughness of the composition can be obviously increased by SiC whisker.The composite of 20 vol% SiC whiskers has a flexure strength of 830MPa and a fracture toughness of 9.8MPa·m 1/2 .When whisker content is over 20 vol%,the strength of the composite is decreased.The strength of the composite are obviously reinforcing by whisker pull out and cracks deflecting.The tensile stress introduced by the difference the thermal expansion coefficient between whisker and the matrix made more ZrO 2(m).ZrO 2(t)martensitic phase transformation occurs obvious ly,and the increases of the whiskers are profitable to the phase transformation during fracture.Both phase transformation toughening and whisker reinforcing are existed in the composite system.