Dislocation densities and dislocation structure arrangements in cold compressed polycrystalline commercial M2052 (Mn–20Cu–5Ni–2Fe) high damping alloy with various strains were determined in scanning mode by X-ray peak profile analysis and electron back-scattering diffraction. The results indicated that the Mn–Cu–Ni–Fe alloy had an evolution behaviour quite similar to the dislocation structure in Cu. The dislocation arrangement parameter showed a local minimum in the transition range between stages III and IV that could be related to the transformation of the dislocation arrangement in the cell walls from a polarized dipole wall into a polarized tile wall structure. This evolution was further confirmed by the results of local misorientation determined by electron back-scattering diffraction. In addition, during deformation, the multiplication of dislocation densities in the MnCu alloy was significantly slower than that in Cu, and the transition of the dislocation structure was strongly retarded in the MnCu alloy compared with Cu. These results could be explained by the mechanism of elastic anisotropy on the dislocation dynamics, as the elastic anisotropy in the MnCu alloy was larger than that in Cu, which could strongly retard the multiplication of the dislocation population and the transformation of the dislocation structure.

Dislocation Structure Evolution and Characterization in the Compression Deformed Mn-Cu Alloy. Y.Zhong, F.Yin, T.Sakaguchi, K.Nagai, K.Yang: Acta Materialia, 2007, 55[8], 2747-56