Y－TZP强化Al_2O_3超细材料的组织性能研究

制备了纳米级Ｙ－ＴＺＰ（Ｙ＿２Ｏ＿３稳定的四方ＺｒＯ＿２多晶）强化Ａｌ＿２Ｏ＿３陶瓷复合材料，并研究了其组织性能。发现纳米粉末有利于提高制品的密度和获得细晶组织。有两种ＺｒＯ＿２粒子存在于该复合材料中，即Ａｌ＿２Ｏ＿３晶内的十分细小的ＺｒＯ＿２粒子和镶嵌于Ａｌ＿２Ｏ＿３晶界的ＺｒＯ＿２粒子，这两种粒子共同作用，十分显著地提高制品的强度，后者还有利于高温性能的改善。２０（ｖｏｌ）％（Ｙ－ＴＺＰ）－Ａｌ＿２Ｏ＿３纳米复合材料的抗弯强度和断裂韧性分别达到１７５０ＭＰａ和６．１ＭＰａ．ｍ￣（１／２）。断裂韧性的缓慢提高主要是由于制品的高密度及晶粒细化的结果。

STUDY ON MICROSTRUCTURE & MECHANICAL PROPERTIES OF Y-TzP STRENGTHENED Al_2O_3 NANOCOMPOSITES

The Y-TZP ( tetr agonal ZrO_2 polycrystal stabilized by Y_2O_3) strengthened Al_2O_3 nanocomposites have been prepared,and their microstructure and mechanical proper ties have also been investigated.It is found that the nanometer size powders are favorable to improve density and to obtain fine grain microstructure,and there are two kinds of ZrO_2 particles in the composites,i.e.,very fine ZrO_2 particles within Al_2O_3 grain and intergranular ZrO_2 stripped on Al_2O_3 grain boundry. They increase obviously the strength of the material, and the later will be beneficial for bettering properties at high telnperature.The flexural strength and fracture toughness of 20vol%(Y-TZP)-Al_2O_3 nanocomposite are 1750MPa and 6.1MPa·m￣(1/2) respectively. The slight enhancement of fracture toughness is mainly caused by high density and grain refinement of the material.