AlN对MoSi_2材料的显微结构与力学性能的影响

EFFECT OF AlN ADDITIVES ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF MoSi2 MATERIAL

研究了ＡｌＮ对热压ＭｏＳｉ２材料的显微结构与力学性能的影响．结果表明，ＡｌＮ与ＭｏＳｉ２原料中的ＳｉＯ２发生反应，生成Ｘ相等．这些相分布在ＭｏＳｉ２晶粒间具有平行于热压平面的取向．在室温下，添加ＡｌＮ提高了ＭｏＳｉ２材料的断裂韧性，最大为４．５ＭＰａ·ｍ１／２．在高温下（１３５０℃），断裂过程中发生屈服现象，复合材料的高温强度比纯ＭｏＳｉ２材料提高两倍。

In this article, the effects of AlN on the microstructure and mechanical properties of hot_pressed MoSi2 material are studied. The results show that during hot pressing process the X phase will be produced by the reaction of AlN with SiO2 existing in MoSi2 powder. The laminated X phase is parallel with the loading plane between MoSi2 grains. At room temperature, MoSi2 composites with AlN additive have the same values of bending strength of monolithic MoSi2, while their fracture toughness all exceeds that of MoSi2 material because of crack branching and deflecting, and the highest value is 4.5 MPam1/2,twice that of pure MoSi2 material. At higher temperature, these composites yield in bending test and yield strength increases to 150 MPa at 1 350 .