无压烧结原位合成制备WSi_2/MoSi_2复合材料及其性能

Preparation of WSi_2/MoSi_2 Composite by In-Situ Synthesis Pressureless Sintering and Its Properties

以钼、硅、钨粉为原料,利用无压烧结原位合成技术制备了不同成分的WSi2/MoSi2复合材料,研究了原位生成的WSi2含量对该复合材料显微结构和力学性能的影响。结果表明:制备的复合材料中除含有以固溶形式存在的WSi2、MoSi2相以外,还有微量的(MoyW1-y)5Si3相;复合材料的力学性能较纯MoSi2的有大幅度提高,其中含20%WSi2复合材料的性能最好,1 000℃的抗弯强度和室温断裂韧度分别为367.3 MPa和7.87 MPa.m1/2;复合材料的强化机制为第二相颗粒强化和固溶强化,韧化机制为第二相颗粒增韧和裂纹偏转。

WSi2/MoSi2 composites with different compositions were prepared by in-situ synthesis pressureless sintering using Mo, Si and W powders as raw materials. The effect of the in-situ synthesized WSiz content on mierostrueture and mechanical properties of the MoSiz composite was studied. The results show that the composite consisted of WSi2 and MoSiz phases which formed as solid-solution, in addition, a few of （MoyW1-y）5Si3 phase was found. Compared with the mono MoSi2, the mechanical properties of the composite improved significantly. The one with 20% WSi2 had the best properties, whose flexural strength at 1 000 ℃ and rooin temperature fracture toughness were 367.3 MPa and 7. 87 MPa · m^1/2 respectively. The strengthening mechanism of the composite was the second phase particles strengthening and solid solution strengthening , and toughening mechanism was the second phase particles toughening and crack deflection.