Microstructure and Mechanical Properties of Co-Cr-Mo-Si-Y-Zr High Entropy Alloy

Abstract

Presented work was focused on obtaining new, up to our knowledge, non-described previously in the literature high entropy Co15Cr15Mo25Si15Y15Zr15 alloy to fill in the knowledge gap about the six-elemental alloys located in the adjacent to the center of phase diagrams. Material was obtained using vacuum arc melting. Phase analysis revealed the presence of a multi-phase structure. Scanning electron microscopy microstructure analysis revealed the existence of three different phases with partially dendritic structures. Chemical analysis showed that all phases consist of all six principal elements—however, with different proportions. Transmission electron microscopy microstructure analysis confirmed the presence of amorphous and nanocrystalline areas, as well as their mixture. For the studied alloy, any phase transformation and solid-state crystallization were not revealed in the temperature range from room temperature up to 1350 °C. Nanoindentation measurements revealed high nanohardness (13(2) GPa and 18(1) GPa for dendritic and interdendritic regions, respectively) and relatively low Young’s modulus (185(23) GPa and 194(9) GPa for dendritic and interdendritic regions, respectively) of the observed phases.

Influence of Hafnium Addition on the Microstructure, Microhardness and Corrosion Resistance of Ti20Ta20Nb20(ZrMo)20−xHfx (where x = 0, 5, 10, 15 and 20 at.%) High Entropy Alloys

“…However, long years of studies have revealed that melting temperatures of the alloying elements ((Tm) i ) should also be considered in the solid solution process. In the literature, the thermodynamical parameter, Ω, described by Zhang et al could be used [ 27 , 28 ].…”

“…Our previous work presents the description of the aforementioned thermodynamical parameters calculations. The physical and chemical properties of all alloying elements in the studied materials have also been described [ 28 , 29 ]. The calculated thermodynamical parameters for all studied Hf-containing HEAs are collected in Table 1 .…”

Influence of Molybdenum on the Microstructure, Mechanical Properties and Corrosion Resistance of Ti20Ta20Nb20(ZrHf)20−xMox (Where: x = 0, 5, 10, 15, 20) High Entropy Alloys

“…Temperature factors such as melting points of alloying elements—T(m)i and an alloy’s empirical melting point—T(m) strongly influence solid solution formation [ 54 ]. A detailed description of the above-mentioned thermodynamic parameters was presented in [ 55 ]. The physical properties of all alloying elements and calculated thermodynamic parameters for studied alloys are presented in Table 1 and Table 2 , respectively.…”

Influence of Zirconium on the Microstructure, Selected Mechanical Properties, and Corrosion Resistance of Ti20Ta20Nb20(HfMo)20−xZrx High-Entropy Alloys

“…For all the studied alloys with various chemical composition, the thermodynamical parameters, such as atomic size mismatch (δ), mixing enthalpy (ΔH mix ), mixing entropy (ΔS mix ), electronegativity differences (Δχ), valence electron concentration (VEC), and Ω parameters, have been calculated ( Table 1 ). The parameters have been discussed in our previous work [ 37 ]. All of the above-mentioned thermodynamical parameters are used for phase formation predictions for high-entropy materials.…”