Molybdenum Disilicide Based Electric Materials Such As Cross-section Channel Angular Pressing

MoSi₂ is one of high temperature electrothermal materials with excellent performance which is appling widely. But in the the sintering process and moulding process, the distribution of powder particles and voids affect the singtering performance of samples immediacy. So it is thoretics and practicality to study the array of particles and voids in order to enhance the density and optimize the performance of M0S12. Equal-channel angular pressing is a valid technology to achieve severe plastic deformation. So far, the main research on ECAP has been conducted on structure, mechanical properties of material deformed by ECAP. There are a few foreign reports on metallic powders consolidation in EACP, Especially, on MoSi₂ electrothermal materials, but no domestic papers.Based on slippage line theory, this paper found the mathematic model under ideal condition and practical condition, and calculate the stress of ECAP. According to it, designing the die of ECAP, which has 0=90°. What' more, conventional area reduction extrusion mould is designed. The study apply two different pressing technology (Equal-channel angular pressing and Conventional area reduction extrusion) in the mould of M0S12, discuss the effect on the microstructure of this material under the different sintering time. It is considered that the particle and porosity are prone to nonuniform in the CE material. After sintering, its density is lower and the factor of porosity is higher, and there are large void and oxide. As a result of severe plastic deformation, the ECAP material can enhance the density and reduce the factor of porosity. It is because that the particle and porosity are uniform , during sintering, the rapidity of the grain growth and void shrink are approximately sameness in different directions, So the grain size are equality ,and the microstructure are more uniform . what's more , on the same molding process, the longer sinter time is, the more grain compact will be ,and the density are higher, microstructure are more uniform.According to Axis-gridding technique, This paper analysis the flow trend of powder particles during ECAP, found the arrange model of particles and voids, discuss the movement of particles and voids, and explain the trial result combined with sintering process.