FRACTURE AND STIFFNESS CHARACTERISTICS OF PARTICULATE COMPOSITES OF DIAMOND IN ZINC-SULFIDE

Diamond particles have been embedded in hot‐pressed zinc sulfide (ZnS) ceramic to improve various mechanical properties while preserving special optical properties. Roomtemperature mechanical tests on small specimens have shown that adding 10 wt% diamond to ZnS has no effect on the yield stress, but increases the tensile strength and the elastic moduli ∼20%, and increases the fracture toughness ∼100%. The doubling in fracture toughness can be explained by elastic interaction of the diamond particles with the crack‐tip stress field. The results and the interpretation presented here are believed to represent a class of composite materials where both constituents are brittle but the dispersed phase has a much higher elastic modulus than the matrix. Copyright © 1990, Wiley Blackwell. All rights reserved