Deformation and fracture in a model brittle particulate composite system: quartz-perspex

Particulate composites are an important class of materials. The relationship between the strength of such composite materials and the constituent materialsʹ properties cannot be reliably predicted. This is particularly true for brittle matrix-brittle particulate systems, e.g. concrete, rock and advanced ceramic composites. The purpose of this article is to report the results of a systematic study of the effect of mean particle (quartz) size in the range 44–1125 μm and volume fractions in the range 0.01–0.5 on the hardness and compressive and tensile strengths of polymethylmethacrylate (perspex) matrix composites. It was found that the hardness results could be reasonably well described by the Hashin-Shtrikman lower bound approximation. The compressive and tensile strengths were decreased by factors of up to 50% and 65% respectively compared with the unfilled matrix. The strengths of the composites were generally dependent on the mean particle sizes, but were only dependent on the volume fraction of particles in some cases.