TEXTURE IN INTERMETALLICS

G. Gottstein, J. Ball, J. Fischer-Bühner, D. Raabe

Institut für Metallkunde und Metallphysik, RWTH Aachen, Kopernikusstr. 14, D-52056 Aachen, Germany

Keywords: Intermetallic Compounds, Deformation Textures, Annealing Textures.

A shape change of crystalline solids is generally accommodated by a shear deformation in order to conserve the crystal structure.Owing to the selection of only few but distinct slip systems during plastic deformation of crystalline solids, non-random crystallographic orientation distributions (textures) develop, which are converted to different but equally pronounced textures upon annealing.

The anisotropy of material properties introduced by these textures is of considerable concern for materials processing and performance. In contrast to pure metals and alloys, where the development of deformation and annealing textures has been extensively explored, little is known about texture evolution in intermetallic compounds. This is due to both the limited formability of most intermetallics at ambient temperature and the more complicated crystal structure of most compounds. There has been substantial progress recently in the development of structural materials on the basis of TiAl, NiAl, and FeAl, where conventional processing can be used for the production of structural components. Consequently, there has been increasing interest in the texture evolution during the processing of intermetallics from the liquid state to the final product. In this contribution we confine our consideration to the NiAl system, in particular Ni₃Al and NiAl. Deformation and annealing textures will be presented and discussed with regard to effect of crystal structure on the mechanism of plastic deformation as well as recovery and recrystallization.