Calculations to introduce some light high entropy alloys based on phase formation rules

Despite high entropy alloys (HEAs), phase formation rules as a simple method have been seldom used to predict the solid solution phases in light high entropy alloys (LHEAs). Some terms and thermodynamic-based parameters are calculated via programing and all 4833 possible quintuple alloys out of proper elements are extracted and categorized in seven alloy groups and fifteen alloy systems with a density less than or equal to 5 g cm−3 defined for LHEAs in this research. As expected, most alloys had low-density elements like Li, Mg, Al, and Ti in their chemical composition. Al14Li11Mg35Ti15Zr25 alloy was identified as the lightest alloy (3.36 g cm−3). Various alloys can be obtained and designed with optimizing values for the atomic size difference, electronegativity difference, and other respective terms. All alloy groups and systems are discussed and limitations for alloying methods are described. Al19Li7Mg6Ti35Nb33 LHEA was chosen as a candidate alloy to fabricate by melting and characterization of the as-cast alloy showed the formation of a high hardness single-phase BCC solid solution structure. Acceptable uniformity in the chemical composition of the alloy with a density of 5.31 g cm−3 confirms the relative reliability of phase formation rules.