Abstract
High-entropy alloys (HEAs) are a new class of solid-solution alloys that have attracted worldwide attention for their outstanding properties. Owing to the demand from transportation and defense industries, light-weight HEAs have also garnered widespread interest from scientists for use as potential structural materials. Great efforts have been made to study the phase-formation rules of HEAs to accelerate and refine the discovery process. In this paper, many proposed solid-solution phase-formation rules are assessed, based on a series of known and newly-designed light-weight HEAs. The results indicate that these empirical rules work for most compositions but also fail for several alloys. Light-weight HEAs often involve the additions of Al and/or Ti in great amounts, resulting in large negative enthalpies for forming solid-solution phases and/or intermetallic compounds. Accordingly, these empirical rules need to be modified with the new experimental data. In contrast, CALPHAD (acronym of the calculation of phase diagrams) method is demonstrated to be an effective approach to predict the phase formation in HEAs as a function of composition and temperature. Future perspectives on the design of light-weight HEAs are discussed in light of CALPHAD modeling and physical metallurgy principles.
Highlights
High-entropy alloys (HEAs) have gained much attention for their ability to expand the limited range of traditional alloys systems and because of their outstanding mechanical properties [1,2,3,4,5,6]
In examining the two plots, it is obvious that the combinations of the thermodynamic parameters can only correctly predict the formation of single-phase solid solutions in classic HEAs, while failing to predict the formation of single-phase solid solutions in light-weight HEAs
The region forming single-phase solid solutions, while the blue region stands for the area forming single-phase solid solutions plus intermetallic phases, and they are separated by the φc = 7
Summary
High-entropy alloys (HEAs) have gained much attention for their ability to expand the limited range of traditional alloys systems and because of their outstanding mechanical properties [1,2,3,4,5,6]. In order to explore advanced light-weight HEAs, it is essential to adjust the alloy composition, and, the resulting constitutive phases in the microstructure in order to achieve the desired physical and mechanical properties, while keeping the density as low as possible. It is important to investigate these empirical phase-formation rules, as applied to light-weight HEAs. CALPHAD (the acronym of the calculation of phase diagrams) method is used here to compare the effectiveness of predicting the single-phase solid solutions versus the empirical parameters. CALPHAD (the acronym of the calculation of phase diagrams) method is used here to compare the effectiveness of predicting the single-phase solid solutions versus the empirical parameters In this regard, many developed formation rules have been summarized and discussed in this paper. Combined with the experimental results, the phase-prediction effectiveness of the phase-formation rules and CALPHAD method for light-weight HEAs are studied as a way to accelerate the design of new light-weight HEAs with targeted properties
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
