The Role of Grain Size and Strain in Work Hardening and Texture Development

Polycrystalline copper (99.999 pct) having four different grain sizes (from 4 to 220 μm) was strained in tension at room temperature to true plastic strains of 0.05, 0.10, 0.20, and 0.30. The initial texture of the materials was determined by neutron diffraction, as were the deformation textures. Both inverse pole figures and calculated TaylorM factors were then derived from the data.

In general, it was observed that the texture strengthens at increasing strain and that the effect of grain size on this development is not very pronounced. The measured change in the volume concentration of the (111) texture component was compared to that obtained from a model simulation, and in general, the experiments and the simulations agreed well.

The effect on the flow stress of the initial texture, and on the texture which develops during straining, could be accounted for on the basis of TaylorM factors calculated from the experimental results, and it was found that there is an effect of texture on the flow stress. The flow stress at strains above yield, expressed as a modified Hall-Petch relationship, was not greatly affected by corrections toM induced by strain and grain size.