Mechanical behaviour and pore morphology of functionally graded alumina preforms and their composites. Issue 8 (July 2023)

• Record Type: Journal Article
• Authors: Ho, Eric; Scarpa, Fabrizio; Su, Bo
• Is Part Of: Journal of the European Ceramic Society. Volume 43:Issue 8(2023)
• Page Start: 3454
• Page End: 3464
• Publication Date: 2023-07
• Subjects: 0000 -- 1111 -- 2000 MSC: 000 0 -- 1 111; Freeze casting -- Gelatine -- Functionally graded -- Composite -- Alumina; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2023.02.033
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Functionally-graded ceramic composites were produced using a hot pour-and-set method via freeze casting of alumina slurries with solid loading between 40% and 20%, with gelatine as a binder. The slurry and additives were tailored for controlling the microstructure and mechanical properties, such as pore morphology, preform density and compressive strength. Varying the gelatine concentration between 2.5% and 9%, transformed the pore morphology from lamelllar to honeycomb and into closed cell. At 3% concentration, increasing the solid loading from 10% to 30% yielded higher compressive strength from 48 MPa to 317 MPa. The resultant compressive behaviour closely matched to Gibson-Ashby closed cell predictive model. Alumina/epoxy composite mechanical performance plateau as the solid loading increased; the 20% solid loading composite produced the best performance. The compressive strengths of the alumina/epoxy and alumina/aluminium composites were on average 300% and 1110% higher than their respective preform counterparts, across a solid loading range of 10–20%.