The plastic compression of copper cones

Annealed and unannealed (i.e. work-hardened) cones of included angles in the range 30°-170° of high-conductivity copper have been quasi-statically compressed against a hard transparent surface and their deformation stress measured under load. It was found that for the unannealed cones the deformation stress increased linearly with the cone angle whereas for the annealed cones the deformation stress peaked at a cone angle in the range 60°-90°. The deformation pattern of the cones has also been investigated and found to be quite different in the two types of cone. The deformation stress versus cone angle behaviour has been explained on the mode of deformation of the two types of cone.