Beryllium strain hardening

The strain hardening is studied of a polycrystalline berillium in various structural states: textured samples of a polycrystalline berillium were subjected to recrystallization annealing at 800 deg C in order to obtain grains of various sizes (from 31 to 116 mcm), irrespective of the strain conditions when tested on the breaking machine. For the berillium of varying grades the hardening process occurs in two parabolic stages. At the second strain stage the hardening coefficient varies similar to the variation of the flow stress with a reference slip, while at the first stage it varies similar to the variation of the flow stress with a prismatic slip