【摘要】 以Mo粉和Si粉为原料,采用热压反应烧结法原位合成了Mo-Si系化合物及其复合材料,利用扫描电镜、X射线衍射仪等技术对材料的相结构和力学性能进行了初步的研究.结果表明:随原料粉中Mo含量的增加,生成物依次向MoSi2→Mo5Si3→Mo3Si变化;材料的硬度和弹性模量主要受气孔率的控制,具有极其弥散组织的Mo5Si3-MoSi2材料的硬度高达12 88GPa;Mo-Si系材料均为脆性断裂,弯曲强度和断裂韧性随Mo含量变化的趋势相同,其中MoSi2-Mo5Si3原位复合材料具有较好的综合力学性能.更多还原

【Abstract】 Mo-Si compound composites were in situ fabricated by means of reactive hotpressing using Mo and Si powder as raw materials. Their phase composition and mechanical properties were investigated for design and fabrication of Mo-Si functionally graded material with hightemperature antioxidation properties in future. The results indicate that the reaction products in Mo-Si system vary in the order of MoSi2→Mo5Si3→Mo3Si with increasing content of Mo in the mixed powders. The hardness and the elastic modulus of insitu synthetic Mo-Si compound composites are mainly controlled by their porosity. The maximum hardness reaches to 1288 GPa in the Mo5Si3-MoSi2composites with very fine dispersive microstructure. The Mo-Si compound composites show macrobrittleness and the same varying tendency in flexural strength and fracture toughness with the change of Mo content. In Mo-Si compound composites, MoSi2-Mo5Si3 composite exhibits good combined mechanical properties.更多还原