Dislocation structures were studied in cyclically deformed single crystals which had been tested at room temperature. The primary slip system, <001>{110}, was found to be operative for the <112> so-called soft orientation. The dislocation structure was found to contain a high density of dipoles and point defect clusters. Dislocation cross-grids were observed which accommodated the misfit between persistent slip bands and the matrix. Possible room-temperature cyclic hardening mechanisms were considered. The dipole density was not uniform, and was found to be modulated on the slip plane. This differed from the case of Ni3Al; which exhibited an homogeneous distribution. Computer simulations of the microstructure were performed on the basis of the dipole diffusion mechanism in a stress gradient.

C.G.Kallingal, T.R.Smith, N.S.Stoloff, K.Rajan: Acta Metallurgica et Materialia, 1994, 42[11], 3731-40