Porosity effect on microstructure, mechanical, and fluid dynamic properties of Ti 2 AlC by direct foaming and gel‐casting

• Published in: Journal of the American Ceramic Society 2018-12, Vol.101 (12), p.5346-5357
• Main Authors: Potoczek, Marek, Chmielarz, Anna, Innocentini, Murilo D. de M., da Silva, Izabela C. P., Colombo, Paolo, Winiarska, Barbara
• Format: Article
• Language: English
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.15802

In this study, Ti 2 AlC foams were fabricated by direct foaming and gel‐casting using agarose as gelling agent. Slurry viscosity, determined by the agarose content (at a fixed solids loading), as well as surfactant concentration and foaming time were the key parameters employed for controlling the foaming yield, and hence the foam porosity after sintering process. Fabricated foams having total porosity in the 62.5‐84.4 vol% range were systematically characterized to determine their pore size and morphology. The effect of the foam porosity on the room‐temperature compression strength and elastic modulus was also determined. Depending on the amount of porosity, the compression strength and Young's modulus were found to be in the range of 9‐91 MPa and 7‐52 GPa, respectively. Permeability to air flow at temperatures up to 700°C was investigated. Darcian ( k 1 ) and non‐Darcian ( k 2 ) permeability coefficients displayed values in the range 0.30‐93.44 × 10 −11  m 2 and 0.39‐345.54 × 10 −7  m, respectively. The amount of porosity is therefore a very useful microstructural parameter for tuning the mechanical and fluid dynamic properties of Ti 2 AlC foams.