Design and mechanical properties of body-centered cubic AlVCr medium-entropy aluminum alloys

Abstract

The formation of brittle intermetallic compounds and the poor solubility of other metallic elements in Al alloys render the design of high- and medium-entropy Al alloys (HEAls and MEAls, respectively) challenging. Herein, new AlVCr MEAls were developed based on a reverse approach, which involved starting from an equiatomic V–Cr alloy. Al20VCr, Al33VCr, and Al50VCr were synthesized as MEAls using a vacuum induction-based melting process. The microstructural evolution and mechanical properties of the synthesized MEAls were carefully investigated. Body-centered cubic single-phases formed in Al20VCr and Al33VCr MEAls, in keeping with thermodynamic calculation results as well as multiple phase-prediction parameters. While Al33VCr exhibited brittle fracturing owing to chemical ordering, Al20VCr MEAl exhibited a compressive strain and yield strength of ∼9.4% and ∼1.0 GPa, respectively. Thus, the reverse approach, which is based on the use of an Al-free system initially, should aid the development of a new class of lightweight HEAls and MEAls.