A High Strength Alumina-Silicon Carbide-Boron Carbide Triplex Ceramic
A ceramic particulate composite composed of oxide, and carbide ceramics was found to have high strength, hardness, and fracture toughness values. A composition consisting of Al2O3 with 15 vol% SiC and 15 vol% B4C additions was produced by hot-pressing at 1650⁰C for 30 min, with full density reached after ~5 min at temperature. Both WB and WB2 were observed, with the W source presumably an impurity from WC milling media, and Al18B4O33 was also detected following densification. Strength was~880 MPa, which is greater than values reported for comparable composites of Al2O3 containing 30 vol% SiC or B4C. Vickers hardness was ~21 GPa, and fracture toughness was ~4.5 MPa m1/2, comparable to values reported for the binary mixtures. The calculated critical flaw size of the material was similar to the size of the SiC/B4C clusters and microcracking at grain boundaries. The latter resulting from thermal expansion mismatch between the Al2O3 matrix and SiC/B4C resuborcing phases.
E. W. Neuman et al., "A High Strength Alumina-Silicon Carbide-Boron Carbide Triplex Ceramic," Ceramics International, vol. 43, no. 10, pp. 7958 - 7962, Elsevier Ltd, Jul 2017.
The definitive version is available at https://doi.org/10.1016/j.ceramint.2017.03.104
Materials Science and Engineering
Keywords and Phrases
Aluminum oxide; Boron carbide; Hot-pressing; Microstructure; Silicon carbide; Strength; Binary mixtures; Fracture toughness; Grain boundaries; Hot pressing; Thermal expansion; Vickers hardness
International Standard Serial Number (ISSN)
Article - Journal
© 2017 Elsevier Ltd, All rights reserved.
01 Jul 2017