The Influence of Chromium Content on the Structural and Mechanical Properties of AlCr_xFeCoNi High Entropy Alloys

Abstract

Many high entropy alloy systems have been exploited in the past decade and among them AlCrFeCoNi alloy is widely studied. The structural and mechanical properties of AlCrxFeCoNi alloy was studied in this paper for different content of chromium (atomic ratio, x= 0.2 to 2.0 at. %). In this study, ten samples having different chemical composition were prepared from raw materials using RAV equipment, type MRF ABJ 900. The microstructure features, crystallite sizes and microhardness depends on chemical composition of the alloy. The microhardness values for AlCrxFeCoNi (x = 0.2 to 2 at. %) increases from 389.6 to 562.6 HV0.1. The maximum value of microhardness for the high entropy alloy AlCrxFeCoNi (x = 1), has been obtained for 20.55 wt% Cr and has the value 562.6 HV0.1.

Characterization and Testing of High-Entropy Alloys from AlCrFeCoNi System for Military Applications

“…The hardness of the experimental materials was determined using the Shimadzu HMV2T microhardness apparatus in Lamet Laboratories from Politehnica University of Bucharest. The measurements were made in line, with mark distances of about 500 μm, using the fingerprint force of 0.1 N and pressing time of 10 seconds [9][10][11][12]. For the Al x Cr y Fe z Co v Ni w system, the entire spectrum of microhardness values in the x = y = z = v = w = 0.2 … 2 at% range was analyzed, as shown in Figure 4.…”

“…High-entropy alloys from the AlCrFeCoNi system feature very good mechanical properties for military applications, as shown in Table 1. Thus, the yield stress, the compressive strength, and the plastic deformation of these alloys reach unexpected values [8][9][10][11][12][13][14][15][16][17][18][19][20], making them usable as composite structures, resistant to dynamic stresses with high deformation velocity, applicable in the field of collective protection [9][10][11][12][13][14][15][16][17][18][19][20].…”

High Entropy Alloys for Medical Applications

“…HEAs are defined as alloys comprising more than five main elements mixed in an equiatomic or near-equiatomic fraction [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Many HEAs have been reported to have: superior mechanical properties, such as ultrahigh fracture even at high temperatures, high hardness, toughness exceeding that of most pure metals and alloys, excellent comparable strength to that of structural ceramics and some metallic glasses, exceptional ductility, and fracture toughness at cryogenic temperatures [1,3], and good physical properties, such as superconductivity, supermagnetism, and significant resistance to corrosion [5].…”

“…Furthermore, the decrease or increase in the ratio of additional elements can generate different metallographic structures with significant influences on the properties of alloys [6][7][8][9][10]. While high-strength conventional alloys are based mainly on the controlled distribution of one or two high-hardness phases at most, in high entropy alloys, the exceptional properties are based on the quenching effect of the supersaturated solid solution and on the suppression of the intermetallic phases [1,[4][5][6][7][8][9][10][11][12]. The complex distribution of the various chemical elements within the crystalline network of high entropy alloys appears to be the main cause of their special characteristics when compared to the classical or bi-component alloys.…”

Effect of Chemical Composition on Hard Deposits Properties in the Case of Weld Refurbishment of Heavy Crushing Hammers

“…In this case, different types of filler material are used to hardfacing the areas affected by wear phenomena. The chemical composition of the filler materials is chosen according to the type of stresses [4 and 5], the technological processes [6][7][8][9], the mechanical and technological characteristics required in operation, economic and endurance considerations, etc. When make hardfacing with alloys having a chemical composition different from that of the base material, it is important to limit the dilution effects and the decrease in the concentration of the chemical elements in the hard deposits.…”