The influence of Al content on pore structures of porous Mo2TiAlC2 ceramics through powder metallurgy technique

Abstract

Porous Mo2TiAlC2 ceramics with different Al content in nominal compositions were fabricated through powder metallurgy technique of Mo, Al, and C elemental powders and TiH2 powders, which were carried out in vacuum environment. Systematic experimental results revealed that the pore structure of these Mo2TiAlC2 ceramics were affected by different Al content significantly. With ascending Al content changed from 0.9 to 1.3 mol, pore sizes and viscous permeability coefficients of these test specimen substantial reduce while volume demonstrated an ascending tendency, the phase is mainly Mo2TiAlC2, and the secondary phase Mo3Al2C decreased with the increase of Al content, and the reason for deviation of molar mass was attributed to the volatilization of Al. When the Al content continues to rise to 1.7 mol, the pore structure parameters including pore sizes, viscous permeability coefficients, and porosities increased, and the impurity phase appeared. Besides, evolution of pore structure parameters in sintering stage and the pore-forming mechanism was explored. The present work is of momentous significance in the preparation of quaternary and multi-element porous MAX phases ceramics/alloys.

Keywords

• powder metallurgy
• mo2tialc2
• porous ceramics
• porosity
• pore forming mechanism