Synthesis of Nanocrystalline and Amorphous Alloys From Elementary Powders by Intensive Plastic Deformation Under High Pressure

Abstract

Transmission electron microscopy is used to study the structure and phase composition of binary zirconium alloys with Group I-VIII metals produced from metal powders via severe plastic torsional deformation under pressure. The metal contents in the initial mixture, the type of reacting metals, and the degree of deformation are found to affect substantially the structure and phase composition of the alloys synthesized. It is found that the tendency of binary zirconium-based alloys to form an amorphous state depends on the position of an alloying metal in the periodic table. An amorphous state is formed in alloys with Group II ( Zn ), III ( Al ), VIII ( Co , Ni ), and I ( Cu ) metals; it is not formed in alloys with Group IV ( Ti ), V (V, Nb ), and VI ( Mo ) metals of the periodic table. Compositions that are close to equiatomic alloys are more favorable for the formation of an amorphous state or the smallest nanograins. In the course of mechanical alloying, high-pressure phases and intermetallic compounds are found to form.

Structure of Al-Fe alloys synthesized from elemental powders by severe plastic deformation under high pressure

“…The methods of energy action on powder mixtures [1][2][3][4][5][6][7][8][9][10][11][12][13] are to the ways that enable one to produce such alloys. Among them, the most promising is the synthesis of alloys from elemental powders through the application of severe plastic deformation under high pressure in Bridgman's anvils [14][15][16][17][18][19][20]. Deformation of powders, unlike deformation of monolithic samples, significantly increases both the refinement degree of forming material and the kinetics of mechanodiffusion due to a considerable increase in the total area of interacting surfaces.…”