Structure and Properties of TiCrFeNiC High Entropy Alloy Produced by Powder Metallurgy

Abstract

The equiatomic high entropy TiCrFeNiC alloy was prepared by sintering or hot forging of preforms from the initial or milled powder mixtures. It is shown that sintering does not provide close to non-porous state of the sintered material. The porosity of the sintered at 1300°C samples from the initial mixture is ≈ 5%, and from milled one ≈ 9%. Minimization of porosity samples (up to 1-1.5 %) was reached only at use of hot forging of porous preforms. Sintered and hot forged alloys consist of predominant high-entropy FCC phase. Dispersed inclusion of titanium carbide particles and a small content of chromium carbide Cr₃C₂ evenly distributed in matrix phase. The hot-forged alloy has a fairly high compressive strength, reaching 2250 MPa, and a hardness of 62 HRC. The annealing after hot forging and increasing of its temperature leads to a monotonic decrease in the level of strength and hardness. Annealing as well increases the level of crack resistance of the alloy, which reaches the value of 14.3 MPa·m¹/².