SiC/Mo界面反应的微观结构及对Mo力学性能的影响

Microstructure of high-temperature interfacial SiC/Mo reaction on Mo and its effect on mechanical properties of Mo

采用XRD、SEM分析测试方法研究在600~1200℃和1800℃真空热处理2 h条件下SiC/Mo界面反应层微观结构,并对SiC/Mo界面反应前后Mo金属的力学性能进行比较。研究表明：在800和1000℃热处理后,Mo与SiC分解的C在表面反应生成Mo2C;在1200℃热处理后Mo表面出现了Mo2C和Mo3Si相,以亚微米颗粒状反应层结构存在;当1800℃热处理后出现了Mo5Si3、Mo5Si3C以及扩散未分解的SiC。采用EDS方法在SiC/Mo界面反应层的断口处确定出Si扩散深度大于C。在600~1200℃热处理后,SiC/Mo界面反应对Mo金属的维氏硬度和延伸率均增大,而拉伸强度改变较小。

This paper aims to investigate the microstructure of interfacial SiC/Mo reaction layer on Mo between 600 - 1 200℃ and 1 800℃ for 2 h by XRD, SEM method, and presents the comparison of mechanical properties between Mo based reaction layer and Mo. The study shows that after 800 and 1 000 ℃ heat treatment, there appears Mo2C on Mo based reaction layer reacting with C from SiC; 1 200℃ heat treatment is followed by appearance of Mo3 Si and Mo2 C, in the interfacial layer with submicrometer grain structure; 1 800 ℃ heat treatment leads to appearance of MosSi3, Mo5Si3C and un-decomposed phase SiC on the reaction layer. Si shows a larger diffusive depth than C on the fracture of Mo based reaction layer, as valued by EDS. Mo based reaction layer, subjected to 600 - 1 200 ℃heat treatment demonstrates a greater Vickers Hardness and specific elongation than Mo, while the tensile strength varies little between Mo based reaction layer and Mo.