XXXVII. Interferometric studies of hardness test indentations: Investigations on tungsten carbide, steel, duraluminium and tin

Abstract

Studies are made on the surface distortions which occur on metal surfaces which have received hardness test indentations from both diamond pyramid and diamond cone indenters. The surface contours are evaluated by multiple-beam interference methods. Experiments are reported for indentations over a wide range of hardness, the surfaces studied being those of sintered tungsten carbide, niekel-steel, duraluminium and tin. The distortions found in polycrystalline masses resemble one another but reveal secondary differences. On single erystallites of tin unsymmetrical patterns are found, with piling-up in two directions and sinking-in in directions at right angles to these. The effects are deternfined by the directions of the crystal axes. The concavity and convexity of the sides of the pyramid indentations axe discussed in relation to piling-up and sinking-in, and the influence of recovery is indicated.