AlN／SiC_w（Y_2O_3＋SiO_2）复合材料热处理增强研究

STUDY ON HEAT-TREATMENT STRENGTHENING OF ALUMINUM NITRIDE-SILICON CARBIDE WHISKER COMPOSITES

研究了热处理对ＡｌＮ／ＳｉＣ_ｗ（Ｙ_２Ｏ_３＋ＳｉＯ_２）复合材料机械性能的影响。结果表明，该材料经热处理后强度提高，当添加剂Ｙ_２Ｏ_３／ＳｉＯ_２＝１／２．５摩尔比时，提高幅度最大。经ＸＲＤ，ＳＥＭ，ＴＥＭ／ＥＤＡＸ和ＨＲＥＭ分析，热处理增强的机理主要是粒界玻璃相在高温氧化气氛中和ＡｌＮ颗粒表层作用，生成的纤维状２Ｈ￣δＳｉａｌｏｎ相和ＳｉＣ_ｗ形成空间交错结构。

The effects of heat treatment on the mechanical properties of AlN-SiC whisker composites with Y_2O_3 and SiO_2 additives are studied. The flexural strength of the composite increases in the heat treatment.When the additives mole ratio Y_2O_3/SiO_2=1/2.5, the increase amplitude is the highest. The phase composition, microstructure and grain boundary phase are characterized by XRD, SEM, TEM/EDXA and HREM combined techniques. The strengthening mechanism of the composites results from crystallization of the glassy phase in the grain boundary at high temperature in oxidizing atmosphere, forming the crossing structure of fibrous 2H￣δsialon phase and SiC whisker.