KNOOP MICROHARDNESS OF SINGLE-CRYSTAL SULFUR

The Knoop microhardness of single crystal sulphur was measured as a fu nction of crystallographic orientation and applied test load on the (1 10) and (111) planes. Microhardnesses were determined to be in the ran ge of 25-35 kg mm(-2). Anisotropy of the microhardness and a normal in dentation size effect (ISE) were observed. The ISE was addressed by th e application of the traditional power law and the proportional specim en resistance model (PSR) of Li and Bradt. The load-independent hardne ss was determined, from which it was concluded that the (111) plane is harder than the (110) plane and also that the (111) plane is more ani sotropic in microhardness.