Database on the mechanical properties of high entropy alloys and complex concentrated alloys

This data article presents the compilation of mechanical properties for 370 high entropy alloys (HEAs) and complex concentrated alloys (CCAs) reported in the period from 2004 to 2016. The data sheet includes alloy composition, type of microstructures, density, hardness, type of tests to measure the room temperature mechanical properties, yield strength, elongation, ultimate strength and Young׳s modulus. For 27 refractory HEAs (RHEAs), the yield stress and elongation are given as a function of the testing temperature. The data are stored in a database provided in Supplementary materials, and for practical use they are tabulated in the present paper. The database was used in recent publications by Miracle and Senkov [1], Gorsse et al. [2] and Senkov et al. [3].


a b s t r a c t
This data article presents the compilation of mechanical properties for 370 high entropy alloys (HEAs) and complex concentrated alloys (CCAs) reported in the period from 2004 to 2016. The data sheet includes alloy composition, type of microstructures, density, hardness, type of tests to measure the room temperature mechanical properties, yield strength, elongation, ultimate strength and Young's modulus. For 27 refractory HEAs (RHEAs), the yield stress and elongation are given as a function of the testing temperature. The data are stored in a database provided in Supplementary materials, and for practical use they are tabulated in the present paper. The database was used in recent publications by Miracle and Senkov [1], Gorsse et al. [2] and Senkov et al. [3].

Subject area
Materials Science More specific subject area High-entropy alloys (HEAs) and complex concentrated alloys (CCAs) Type of data  [2].

Value of the data
The database covers the main mechanical properties of HEAs and CCAs tested under uniaxial loading from published reports since 2004 until end of 2016.
The database can be used to assess the potential of HEAs and CCAs as possible structural materials. The database can be used to represent various property spaces and calculate performance indices. The database can enable data mining to extract insights and uncover patterns to guide and accelerate the development of HEAs and CCAs.

Data
High entropy alloys (HEAs) and complex concentrated alloys (CCAs) represent a new branch of the metallic alloy tree. HEAs are defined as alloys with 5 or more principal elements that have concentrations between 5 and 35 atom percent, promoting the formation of single-phase-disordered solid solutions presumably stabilized by the configurational entropy of mixing. CCAs encompass all alloys, including HEAs, with three or more principal components. CCAs can have single-phase or multi-phase microstructure.
A detailed comparison of CCAs with competing commercial alloys is crucial to identify the most attractive alloys for structural applications and guide future studies [1][2][3]. The relative merits of these new alloys depend on combinations of properties specific to the applications and loading conditions. Thus, this data article is a compilation of the density and mechanical properties of CCAs published in the literature since 2004, allowing the performance indices for lighter, stronger and stiffer structures to be evaluated for different loading conditions [2]. The data are stored in a database and tabulated in the present article.

Experimental design, materials and methods
The database has a tree-like classification ( Fig. 1) which includes four different families: 3d transition metal (3d TM), refractory metal (RHEAs and RCCAs), light metal family, and bronzes and brasses HEAs/ CCAs. Each family is expanded in classes (a class is a unique combination of principal elements), and each class contains members having variations in principal element concentrations. Each member is characterized by a set of attributes which includes: alloy composition, phase content, density, hardness (Vickers), type of mechanical test (tension or compression), yield strength, ultimate strength, elongation, and Young's modulus. A listing of these entries makes up a material record. The database was used by Gorsse et al. [2] with Cambridge Education Software (CES) enabling users to (i) browse the materials data, (ii) search and filter to narrow down the set of materials using given parameters (e.g. alloy composition that contains a specific chemical element), (iii) represent material property maps by plotting any properties or combination of properties against any other property, and (iv) select materials using performance indices as defined by M. F. Ashby.
A representation of the data is illustrated in Fig. 2 where the room temperature yield strength is plotted against the density for CCAs.
Since this work reflects the state of the art of the field of HEAs and CCAs, the properties are not equally populated for every alloy due to the lack of literature data. The density of the alloy was estimated using the rule of mixtures (ROM): ρ ¼ P x i M i = P x i V i where x i , M i and V i are the atomic fraction, molar mass and molar volume of the element i. When not experimentally measured, the Young's modulus was estimated using ROM for single phase solid solutions only: E ¼ P x i E i where E i is the Young modulus of the alloy element i.
For practical use by all, the data are also given in the present article using Tables and shared on Google Drive via the following link: https://docs.google.com/spreadsheets/d/1hLiqmlysSKK7Ubv362v8 fasoh8-W17V7zqNzRfSoilw/edit?usp¼ sharing. The main entries for 370 alloy compositions are listed at room temperature in Table 1, while Table 2 shows the temperature dependence of the mechanical properties for 27 HEAs/CCAs. Each row in Table 1 corresponds to one mechanical test for an alloy composition in an experimentally characterized metallurgical condition.   Table 1 HEAs and CCAs for which mechanical tests are reported in literature. ρ represents the density, HV is the hardness in Vickers, σ Y is the Yield strength, σ max is the ultimate strength, ε is the elongation and E is the Young's modulus. Parentheses indicate values estimated using ROM. In the column "Type of tests", C and T stands for compression and tension. Im stands for Intermetallic. Each row represents the result of a test on a specific alloy composition.
Type of phases 3d TM HEAs and CCAs in the Al-Co-Cr-Fe-Mn      Table 2 HEAs and CCAs for which mechanical tests are reported in literature as a function of temperature.