A high strength alumina-silicon carbide-boron carbide triplex ceramic. Issue 10 (July 2017)

• Record Type: Journal Article
• Authors: Neuman, Eric W.; Hilmas, Gregory E.; Fahrenholtz, William G.
• Is Part Of: Ceramics international. Volume 43:Issue 10(2017)
• Page Start: 7958
• Page End: 7962
• Publication Date: 2017-07
• Subjects: Aluminum oxide -- Silicon carbide -- Boron carbide -- Strength -- Microstructure -- Hot-pressing; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2017.03.104
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: 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 Al2 O3 with 15 vol% SiC and 15 vol% B4 C additions was produced by hot-pressing at 1650 °C 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 Al18 B4 O33 was also detected following densification. Strength was ~880 MPa, which is greater than values reported for comparable composites of Al2 O3 containing 30 vol% SiC or B4 C. Vickers hardness was ~21 GPa, and fracture toughness was ~4.5 MPa m ½, comparable to values reported for the binary mixtures. The calculated critical flaw size of the material was similar to the size of the SiC/B4 C clusters and microcracking at grain boundaries. The latter resulting from thermal expansion mismatch between the Al2 O3 matrix and SiC/B4 C reinforcing phases.