The effect of annealing at 800 C or 1000 C for 100 h on the structure and mechanical properties of refractory AlCr x NbTiV and AlNbTiVZr x (x ¼ 0e1.5) high-entropy alloys was studied. In the initial condition (annealing at 1200 C for 24 h), the AlNbTiV and AlCr 0.5 NbTiV alloys were composed of the B2 phase while the AlCrNbTiV and AlCr 1.5 NbTiV alloys had a mixture of the B2 and Cr 2 Nb-type C14 Laves phases. The AlNbTiVZr x (x ¼ 0.5e1.5) alloys in the initial condition consisted of the B2, Zr 5 Al 3 -type, and ZrAlVtype C14 Laves phases. Annealing of the AlCr x NbTiV (x ¼ 0e1.5) alloys at 800 C or 1000 C resulted in (i) precipitation of the Nb 2 Al-type s-phase or an increase in the fraction of the Laves phase; (ii) an increase in the microhardness and a pronounced drop in ductility. Annealings of the AlNbTiVZr x (x ¼ 0.5 e1.5) alloys at 800 C or 1000 C led to insignificant changes in the structure and microhardness but somewhat decreased ductility. Quasi-binary AlNbTiV-Cr and AlNbTiV-Zr phase diagrams constructed with a Thermo-Calc software and TCHEA2 database were used to analyze phase transformations in the experimental alloys. The differences in the behavior of the Cr/Zr-containing alloys and the relationships between the phase composition and mechanical properties of the alloys were discussed.
High-pressure torsion (HPT) at room temperature was applied to an AlNbTiVZr 0.5 refractory high entropy alloy. In the initial as-cast condition the alloy was composed of a coarse-grained B2 matrix phase and a continuous network of C14 Laves phase particles with the volume fraction of 19%. HPT resulted in the formation of a nanocrystalline structure in the B2 matrix with an average size of grains/subgrains of 25 nm after 5 revolutions. The B2 phase also underwent significant disordering during HPT. The Laves phase network was broken and individual particles became much thinner in comparison with those in the initial condition. Microhardness measurements have revealed typical of HPT gradient along the radius which decreased with increasing the number of revolutions. It was also found that the nanohardness of the B2 phase increased after HPT while the nanohardness of the Laves phase decreased. A strong decrease in the Young's modulus of the B2 phase was also found. Factors governing structure and properties evolution of the alloy during HPT were discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.