Strength and dislocation density of Ni3Al alloys

Dislocation density in Ni-3(Al,Hf) single crystals was measured for various strains and temperatures and a detailed discussion about its correlation with stress is presented. The usual Taylor equation faces to some objections, especially the necessity to change systematically the parameter alpha with temperature. The applied stress is not proportional to the square root of measured dislocation density at the onset (gamma less than or equal to 3%) of the plastic deformation. An alternative explanation of the strain hardening based on the stress necessary for activation of Frank-Read sources is proposed.