Hardness of a surface containing uniformly spaced pyramidal asperities

Pyramidal asperities of different apical angle were machined on a flat copp er surface. Hardness was estimated from the load-displacement graphs obtain ed by pressing a spherical rigid indenter onto the asperities. The variatio n of hardness with apical angle and pitch was recorded with a view to contr ibuting to the development of a general framework for relating measured har dness to the surface roughness.