高温氧化性能的影响
(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 以Mo、W和Si粉为原料，采用自蔓延热爆合成和热压工艺制备不同W含量的(Mo1−x, Wx)Si2复合材料，研究W含量对(Mo1−x, Wx)Si2复合材料的力学性能和高温抗氧化性能的影响。结果表明：随着W含量的增加， (Mo1−x, Wx)Si2复合材料的力学性能逐渐增加，氧化激活能逐渐降低；(Mo0.5,W0.5)Si2复合材料的室温抗弯强度、 1 200 ℃高温抗弯强度、硬度和断裂韧性分别为363 MPa、480 MPa、9.28 GPa和3.82 MPa∙m1/2，与纯MoSi2比较，分别增加了40.7%、112.4%、12.1%和27.3%；(Mo1−x, Wx)Si2复合材料在1 673~1 873 K空气中能形成致密的氧化层，氧化增量符合抛物线规律。
关键字: 二硅化钼；合金化；力学性能；氧化行为
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:(Mo1−x, Wx)Si2 composites were prepared by the thermal explosion mode of SHS followed by hot pressing using Mo, W and Si powders as raw materials. The effect of W content on the mechanical properties and high temperature oxidation behavior of (Mo1−x, Wx)Si2 composites were studied. The results show that with increasing W content, the mechanical properties of (Mo1−x, Wx)Si2 composites gradually increase, and the activation energies of (Mo1−x, Wx)Si2 composites gradually decrease. The room temperature bending strength, high-temperature flexural strength at 1 200 ℃, hardness and fracture toughness of (Mo0.5, W0.5)Si2 composite are 363 MPa, 480 MPa, 9.28 GPa and 3.82 MPa∙m1/2, respectively, increased by 40.7%, 112.4%, 12.1% and 27.3% when compared with those of the monolithic MoSi2. (Mo1−x, Wx)Si2 composites can form compact oxidation layers in the air at 1673−1 873 K, and oxidation mass gain is accordance with parabolic law.
Key words: molybdenum disilicide; alloying; mechanical properties; oxidation behavior
