热压法制备Mo_5Si_3-Al_2O_3复合材料及力学性能研究

Mechanical properties of Mo_5Si_3-Al_2O_3 composite prepared by hot-pressing

以MoO_3粉、Mo粉、Si粉和Al粉为原料,采用机械合金化结合热压烧结法制备了Mo5Si3-Al_2O_3复合材料,研究了Al_2O_3含量对Mo5Si3-Al_2O_3复合材料微观结构和力学性能的影响。结果表明：复合材料的主要物相组成为Mo5Si3、Al_2O_3和Mo3Si,其平均晶粒尺寸在51~99 nm之间,具有纳米晶结构。Al_2O_3的引入细化了晶粒,提高了复合材料的致密度和力学性能。Mo5Si3-30%Al_2O_3复合材料的致密度、硬度、抗弯强度和断裂韧性分别为99.6%、13.2 GPa、322 MPa和6.43 MPa·m1/2。

Mo5Si3-Al_2O_3 composites were fabricated using Mo O3,Mo,Si and Al as starting materials by mechanical alloying and hot-pressed sintering method. The effects of Al_2O_3 content on microstructure and mechanical properties of the Mo5Si3-Al_2O_3 composites were investigated. The results show that the main phase of the composites are Mo5Si3、Al_2O_3and Mo3 Si. The grain size of Mo5Si3、Al_2O_3and Mo3 Si are 51 ~ 99 nm and the Mo5Si3-Al_2O_3 composites have nano-crystalline structure. Addition of Al_2O_3 may refine grain of the composites,and improve their density and mechanical properties. The density,hardness,flexure strength and fracture toughness of Mo5Si3-Al_2O_3 composites are 99. 6% 、13. 2 GPa、322 MPa and 6. 43 MPa·m1 /2,respectively.