在研究了AlN-多型体15R,12H和21R的形成特性的基础上［1］,本工作测定了它们的力学性能，并利用SEM观察了显微结构.结果表明,尽管AlN-多型体的力学性能较差，但是具有适当烧结添加剂的AlN-多型体的抗折强度在室温至1250°C的范围内能保持不变，甚至提高50%,尤其是15R和12H.AlN-多型体的硬度随其组份向AlN方向靠近而增加，即21R的硬度最高(12.714.4GPa)，15R的硬度为最低(11.512.8GPa).AlN-多型体的强度和断裂韧性与AlN-多型体的类型之间没有这种明显的联系，它们的变化范围分别在313366MPa和3.84.8MPa1/2之间.本文依据AlN-多型体的结构特征及断裂形貌对它们的力学性能进行了讨论.
Based on our previous study on formation and densification behavior of AlN-polytypoids (15R, 12H, 21R)［1］, their mechanical properties and microstructure were studied. The results show that the AlN-polytypoid phases possess relatively poor mechanical properties, however, their flexural strength can remain constant(21R) or increase as high as 50%(15R and 12H) from room temperature till 1250C. The hardness varies with the species of AlN-polytypoids and the additives used in a range of 11.514.4GPa(Hv10). The 15R compositions possess the lowest hardness varying from 11.5 to 12.8GPa. For 12H and 21R compositions, the varying range increases to 12.613.8GPa and 12.714.4GPa, respectively. The longer stacking sequence in AlN-rich polytypoids is responsible for its higher hardness because of the longer Burgers vector required for slip dislocations. The fracture toughness and flexural strength has no such close relationships to the type of AlN-polytypoids. They varied in the range of 3.84.8MPa1/2 and 313366MPa, respectively. The pull out and micro-cracks formed in the AlN-polytypoids grains are supposedly the main mechanisms for the strengthening effect at high temperature
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