摘要
在研究了 ＡｌＮ－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ＡＩＮ－多型体的力学性能较差，但是具有适当烧结添加剂的ＡＩＮ－多型体的抗折强度在室温至１２５０℃的范围内能保持不变，甚至提高５０％；尤其是１５Ｒ和１２Ｈ．ＡＩＮ－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（１２．７～１４．４ＧＰａ），１５Ｒ的硬度为最低（１．５～１２．８ＧＰａ）．ＡＩＮ－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３１３～３６６ＭＰａ和３．８～４．８ ＭＰａ·ｍ^（１／２）之间．本文依据 ＡＩＮ－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 AIN-polytypoids (15R, 12H, 21R)[1], their mechanical properties and microstructure were studied. The results show that the AIN-polytypoid phases possess relatively poor mechanical properties, however, their fie-cural strength can remain constant(21R) or increase as high as 50%(15R and 12H) from room temperature till 1250℃. The hardness varies with the species of AIN-polytypoids and the additives used in a range of 11.5～14.4GPa(H_(v10)). The 15R compositions possess the lowest hardness varying from 11.5 to 12.8GPa. For 12H and 21R compositions, the varying range increases to 12.6～13.8GPa and 12.7～14.4GPa, respectively. The longer stacking sequence in AIN-rich polytypoids is responsible for its higher hardness because of the longer Burgers vector required for slip dislocations. The fracture toughness and fie-cural strength has no such close relationships to the type of AIN- polytypoids. They varied in the range of 3.8～4.8MPa·m^(1/2) and 313～366MPa, respectively. The pull out and micro-cracks formed in the AIN-polytypoids grains are supposedly the main mechanisms for the strengthening effect at high temperature.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2000年第4期756-760,共5页
Journal of Inorganic Materials
基金
国家自然科学基金重点项目资助!(59632100)
关键词
多型体
稀土氧化物
力学性能
结构
氮化铝
陶瓷
AlN-polytypoids
Sialon
rare-earth oxides
mechanical properties
microstructure
