High-Toughness Silicon Carbide as Armor
Abstract:Silicon carbide, with single-edge precracked beam (SEPB) toughness greater than 7 MPa·m1/2, was made by hot-pressing using Al–B–C (ABC) or Al–Y2O3 (YAG) as additives. The hardness of SiC processed with a liquid phase was always less than SiC densified without a liquid phase despite having a similar or finer grain size. With increasing Al content, the ABC system changed from trans- to intergranular fracture with a drop in hardness and a two- to threefold increase in SEPB toughness. Strength and Weibull modulus for materials processed with a liquid phase were higher than those of solid-state densified SiC. Ballistic testing, however, did not show any improvement over SiC densified with B and C additives. Depth of penetration was controlled by hardness of the SiC-based materials, while V50 values for 14.5 mm WC–Co cored projectiles were in the range of 720–750 m/s for all materials tested.
Document Type: Research Article
Affiliations: Ceramatec, Inc., Salt Lake City, Utah 84119
Publication date: August 1, 2005