Multi-principle element alloys (MPEAs, among which alloys with ≥5 elements are also called high entropy alloys, HEAs) are a new alloy development philosophy 1, 2, where the base alloy has significant atom fractions of several elements. This strategy optimizes a suite of properties while retaining the characteristic properties of the base element that make this alloy family attractive. As many as a dozen other elements may be added, but conventional alloys still usually have a majority atom fraction of the base element. As the number of elements increases, the configurational entropy rises slowly while the probability of at least one pair of elements favouring formation of intermetallic compounds increases more rapidly, explaining this apparent contradiction.Ĭonventional alloys have one principal element, with minor modifications achieved by adding relatively small amounts of other elements. This contradicts the major premise of HEAs-that increased configurational entropy increases the stability of disordered solid solution phases. We find the surprising result that solid solution alloys become less likely as the number of alloy elements increases. ![]() We evaluate over 130,000 alloy systems, identifying promising compositions for more time-intensive experimental studies. Here we develop a new approach to rapidly assess structural metals by combining calculated phase diagrams with simple rules based on the phases present, their transformation temperatures and useful microstructures. ![]() Recent multi-principal element, high entropy alloy (HEA) development strategies vastly expand the number of candidate alloy systems, but also pose a new challenge-how to rapidly screen thousands of candidate alloy systems for targeted properties.
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