An approach to design single BCC Mg-containing high entropy alloys for hydrogen storage applications

• DOI: 10.1016/j.ijhydene.2021.05.087
• Publication Date: 2021-06-06T11:03:00Z
• Authors: R.B. Strozi; D.R. Leiva; J. Huot; W.J. Botta; G. Zepon
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract Mg is a lightweight element that can increase the gravimetric hydrogen storage capacity of high entropy alloys (HEAs). This work presents a new approach to design single-phase Mg-containing HEAs with attractive hydrogen storage properties. The design method is based on four calculated parameters (ϕ, VEC, Δ H ∞ ¯ and Δ H f o ¯ ) that allow us to find alloy compositions that form single body-centered cubic (BCC) solid solutions with high hydrogen affinity. The method was tested in the Mg–Al–Ti–Mn–Nb system and the Mg12Al11Ti33Mn11Nb33 alloy was selected among 1326 calculated compositions. This alloy was produced by high energy ball milling resulting in a homogeneous single-phase BCC alloy that absorbed 1.7 wt.% of H by forming a BCC monohydride. Despite its H uptake being H/M = 1, the gravimetric capacity of the lightweight Mg12Al11Ti33Mn11Nb33 alloy was comparable to refractory BCC-HEAs with H uptake of H/M = 2.