Plastic compression of spheres

Abstract

An experimental investigation is reported of the compression of metal spheres between smooth parallel platens. Measurements have been made of the mean contact pressure P as a function of the radius of the contact area a. For work-hardened metals, P was found to increase to a maximum value of 0·7 to 0·8 times the Vickers hardness of the sphere material, at a value of a/R ≃ 0·20 to 0·28, where R is the radius of the sphere before deformation. The contact pressure then declined steadily with increasing a/R. Annealed metals showed oither no maximum in pressure, or a very broad peak. Qualitative explanations of these results are given by analogy with other deformation geometries.