HIGH-ENTROPY ALLOYS OF HF-MO-TA-W TYPE WITH NB OR NI CONTENT, MEANT FOR MANUFACTURING HIGH KINETIC ENERGY PENETRATORS AND CONSOLIDATION METHOD

The invention relates to high-entropy alloys of the HfMoNiNbTaW multi-element system meant for the manufacturing of high kinetic energy penetrators with high density and hardness, with resistance to impact and high compressive properties and to a process for the consolidation thereof. According to the invention, the alloys are made each of five metal elements of purity>99.5% having the following chemical compositions, the percentage being expressed by weight: a. Hf =25...26.5%, Mo =13...14%, Ni =7...8%, Ta = 26...27.5%, W = 27...28.5% for the HfMoNiTaW alloy and b. Hf = 24.5...26%, Mo = 12...13%, Nb = 6...8%, Ta = 26.5...28%, W = 28...29% for HfMoNbTaW alloy, with densities ranging between 13.5...14.5 g/cm3 and melting temperatures ranging between 2500...2700°C, materials which have, in the cast state, average values of micro-hardness of 550 HV0.5, for the first alloy, and 650 HV0.5, for the second, respectively, while, after applying the homogenization heat treatments for consolidation, they have an associated hardness of 570 HV0.5 for the first alloy and 760 HV0.5 for the second alloy, respectively, the alloys being made by melting and homogenization in a vacuum arc remelting plant under protective argon atmosphere. The claimed consolidation process consists in covering the alloys with aluminum foil, coating them with kaolin paste, introducing them in a metal crucible under a protective layer of quartz sand to prevent oxidation, followed by heat treatments consisting in heating up to 900°C, maintaining at said value plateau for 2 hours and quench hardening in water.