THE INFLUENCE OF SYNTHESIS PROCESS MODES ON THE PHASE COMPOSITION, STRUCTURE, AND PROPERTIES OF THE HIGH-ENTROPY Ti–Cr–Fe–Ni–Cu ALLOY

Abstract

The influence of production modes on the structure, phase composition, and properties of the high-entropy Ti–Cr–Fe–Ni–Cu alloy has been studied. The starting materials were Cr, Fe, Ni, Cu, and Ti powders in the equiatomic ratio. To prepare the starting charge, the powders were mixed and mechanically alloyed in a planetary-ball mill. The compacted billets were hot-forged and then annealed at 1000, 1100, and 1200 ºС. The phase composition of the hot-forged and annealed alloys is mainly represented by fcc structures. There are few peaks of bcc structures, intermetallides, and titanium. Mechanical synthesis leads to significant distortion of crystalline lattices of all elements of the powder mixture, which is evidenced by substantial expansion of interference lines. Annealing of the hot-forged samples and increase in the annealing temperature decrease hardness and lattice distortion. The materials made of the starting mixtures subjected to preliminary mechanical activation show higher hardness. The hardness increases with grinding time for both unannealed samples and those annealed at all temperatures concerned.