Lightweight AlCuFeMnMgTi High Entropy Alloy with High Strength-to-Density Ratio Processed by Powder Metallurgy

Abstract

In this study, we synthesized a new Al 16.6 Cu 16.6 Fe 16.6 Mn 16.6 Mg 16.6 Ti 16.6 lightweight high entropy alloy (LWHEA) by high energy ball milling and spark plasma sintering (SPS). The effect of milling time (15, 30, 45, and 60 h) and SPS conditions (600 and 700 °C) on microstructure, hardness, and density of LWHEAs were studied. The results showed that milled LWHEA is base centered cubic (BCC) structured, consisting of dual BCC1/BCC2 matrix with dispersed minor Cu 2 Mg precipitates and Ti. After SPS of milled samples, the BCC2 phase fraction was increased gradually. The distribution of Ti was uniform up to 45 h milled sample SPSed at 600 °C. However, porosity was built up beyond 45 h milling and higher SPS temperature (700 °C). The presence of finer secondary phases in the HEA matrix contributes to the dispersion hardening. The optimum microhardness and density of LWHEA AlCuFeMnMgTi were around 770 HV and 4.34 g cm − 3 which is superior to other conventional alloys such as Al or Ti-based alloys.

High Entropy Alloy Coatings and Technology

“…Various refractory HEAs developed so far are TaNbCrMo, TaMoNbW, TaNbZrHf, CrNbVZr series [31,32]. Metallic lightweight alloys have also been researched based on light elements to reduce their density for various lightweight structural applications, such as AlCuSiZnFe, AlLiMgScTi, AlCuFeMnMgTi, Al 20 Be 20 Fe 10 Si 15 Ti 35 , etc [23,[36][37][38].…”

Effect of light (X = Mg, Si) and heavy (X = Zn) metals on the microstructural evolution and densification of AlCuFeMnTi-X high-entropy alloy processed by advanced powder metallurgy

“…The average microhardness of the developed HEAs was determined by a Vickers hardness tester (Mitutoyo HM200, Japan) at a load of 100 gf for 10s. The relative density was determined from the measured and theoretical density of the developed HEAs [8,13].…”

“…In addition, there is little research on low-density HEAs composed of Mg and Si which are important for weight reduction and fluidity in automotive components. Transition metals have been added with or without Al to improve strength but at the expense of the density which is in the vicinity of 7.0 g cm −3 [8].…”

“…To prepare lightweight HEAs, authors have used various light elements in the past, such as Li, Be, Sc and heavy elements like V, Zn, etc. [6][7][8]. Most of these elements are either toxic or expensive elements to be used for commercialisation.…”

Tailoring Compressive Strength and Absorption Energy of Lightweight Multi-Phase AlCuSiFeX (X = Cr, Mn, Zn, Sn) High-Entropy Alloys Processed via Powder Metallurgy

“…Other researchers also produced a lightweight Al 20 Be 20 Fe 10 Si 15 Ti 35 HEA by casting with a density of 3.91 g/cm 3 and hardness of −911 HV [17]. However, most of the lightweight HEAs contain toxic, expensive, and scarce elements [18][19][20]. Various strengthening mechanisms, such as solid-solution hardening, grain refinement, precipitation hardening, and heterogeneous structure hardening, have been recommended to balance strength and plasticity Materials 2021, 14, 4945 2 of 13 in the existing HEAs [21][22][23][24][25].…”