Al2O3–B4C–Al Composite Material Systems via Pressureless Infiltration Methods

Abstract

Modification of the Al2O3–Al system's chemistry via the addition of B4C is described and is shown to result in fully dense structures via wetting techniques at high temperatures, without the need for pressure‐assisted infiltration. The relationships between the surface area of boron carbide and alumina powders, the effectiveness of infiltration, the material chemistry following infiltration, and the resulting mechanical properties of Al2O3–B4C–Al composites are evaluated. Additional approaches, including the incorporation of aluminum metal powder as an additional wetting agent before infiltration, are described in conjunction with a variation of both the surface areas and the volumetric ratios of inert Al2O3 to reactive B4C phases. These methods can provide the means to achieve low‐cost metal matrix composites in both vacuum and argon infiltration environments, and represent an approach that enables the generation of articles with complex geometries, requiring minimal secondary finishing treatment.