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研究了１５ｍｏｌ％Ｙ２Ｏ３－Ｌａ２Ｏ３热压自韧Ｓｉ３Ｎ４的β－Ｓｉ３Ｎ４晶粒生长对强度、韦伯模量和断裂韧性的影响。在最佳的工艺条件下，其强度、断裂韧性和韦伯模量分别为９６０ＭＰａ、１１．７２ＭＰａ·ｍ１／２和２４．５。实验结果表明，烧结温度和时间对β－Ｓｉ３Ｎ４晶粒生长及力学性能有重要影响。随烧结温度升高，其强度、断裂韧性和韦伯模量值上升；超过１８００℃，其力学性能有一定下降。过长的烧结时间，将使β－Ｓｉ３Ｎ４晶粒粗大，因而其性能降低。韦伯模量取决于β－Ｓｉ３Ｎ４晶粒尺寸分布和显微结构均匀性。ＳＥＭ观察表明，裂纹偏转是该材料的主要增韧机制。另外，较大β－Ｓｉ３Ｎ４晶粒的拔出和裂纹分支也对增韧有所贡献。
The effect of the grain growth of β-Si3N4 on the strength, Weber modulus and fracture toughness of 15mol% Y2O3-La2O3 hot pressed Si3N4 was studied. Under the optimum conditions, the strength, fracture toughness and Weber modulus were 960MPa, 11.72MPa · m1 / 2 and 24.5, respectively. The experimental results show that the sintering temperature and time have an important influence on the grain growth and mechanical properties of β-Si3N4. With the increase of sintering temperature, the strength, fracture toughness and Weber modulus increase; when the temperature exceeds 1800 ℃, the mechanical properties will decrease. Too long sintering time will make the β-Si3N4 grains coarser, so its performance will decrease. Weber modulus depends on the β-Si3N4 grain size distribution and microstructure uniformity. SEM observation shows that the crack deflection is the main toughening mechanism of the material. In addition, the larger beta-Si3N4 grain pull-out and crack branches also contribute to toughening.