Al(Cr)_2O_3-Cr(Mo)陶瓷基复合材料的制备与组织

Preparation and microstructure of Al(Cr)_2O_3-Cr(Mo) ceramic matrix composites

在Al-Cr2O3体系中引入稀释剂(Al2O3、Cr2O3)和反应性添加剂(MoO3)。利用热爆式燃烧合成法成功制备了含有细小棒状金属相共晶体的Al(Cr)2O3-Cr(Mo)陶瓷基复合材料。探讨了反应体系成分和制备工艺对复合材料微观组织的影响。对燃烧合成熔体施加1.26 MPa压力,致密度可达90%左右。陶瓷基体具有3种形态:边界较圆整的块状,细小的、按一定的取向交叉排列的长条状以及粗大的长条状。金属相以颗粒状分布在陶瓷晶体内或晶界处,或与陶瓷相形成共晶组织。产物的共晶体呈准规则的结构,细小棒状的金属相弥散分布在连续的陶瓷基体中。共晶体的分布具有区域性。原位生成的长条状陶瓷晶粒及金属相呈棒状的共晶结构是制得的复合材料的重要组织特征。

The diluents （Al2O3, Cr2O3） and reactive additive （MoO3） were added to Al-Cr2O3 system. Al（Cr）2O3-Cr（Mo） ceramic matrix composites with eutectic mixture of fine rod metal phase were successfully fabricated by means of the thermal explosive combustion synthesis method. The effects of the reactive system composition and preparation process on the microstructure of the composites were investigated. The products with about 90 percent relative density were obtained at a pressure of 1. 26 MPa on the synthesized material melt. The ceramic phase has three morphologies, block grains with round edges, fine rectangular slab grains with different orientations and coarse rectangular slab grains. Metal particles distribute intragranularly or intergranularly in the ceramic crystal grains, or eutectic structure forms. The eutectic mixture has a quasi-regular structure. The fine rod metal phase disperses in the continued ceramic matrix. The eutectic mixture is regionally distributed throughout the specimen. The microstructures of the fabricated composites are principally characterized by in situ rectangular slab ceramic grains and the rod eutectic mixture.