Evolution of the Structure and Phase Composition of Rapidly Quenched Ribbons of Al-Fe Alloys during Severe Plastic Deformation

摘要

Specific features of phase and structure transformations upon severe plastic deformation by torsion in Al-Fe thin ribbons produced by melt quenching have been studied. Using transmission electron microscopy, X-ray diffraction, and Mossbauer spectroscopy, it has been found that the rapidly quenched alloys with 1-4 at percent Fe contain nonequilibrium structures consisting of a metastable eutectic (formed by aluminides Al_(13)Fe_4 with a rhombohedral lattice and an a solid solution) and primary metastable aluminides Al_mFe with a tetragonal lattice. It is shown that the severe plastic deformation of these materials results in changes in the phase composition, a refinement of structure constituents, and the formation of aluminum-based solid solutions supersaturated with iron. Their formation is initiated by the dissolution of metastable iron aluminides. Melt quenching and severe plastic deformation by torsion allow one to produce in the Al-4 at percent Fe alloy two-phase nanocomposite materials with a hardness to 3 GPa.