This study introduces an innovative approach to alloy design by experimentally validating the semi-empirical concept of Griessen and Driessen, which predicts the hydrogen affinity of solid solutions. The work focuses on designing and synthesizing four equiatomic high-entropy alloys (HEAs) with compositions tailored to exhibit highly endothermic enthalpies of solution and formation, resulting in resistance to hydrogen absorption. Unlike conventional studies that prioritize hydrogen storage capacity, this research uniquely targets alloys optimized for minimal hydrogen interaction, addressing critical needs in hydrogen storage and transportation technologies prone to hydrogen embrittlement. Experimental results confirm the negligible hydrogen absorption of these alloys, with a maximum of 0.23 wt.% (H/M = 0.13) at 2 MPa and 175 °C. This study not only demonstrates the applicability of a theoretical model to guide alloy design but also highlights the potential of these materials for low-pressure hydrogen storage systems, where mechanical integrity and resistance to hydrogen degradation are paramount. The findings bridge the gap between theoretical predictions and practical applications, offering a novel perspective on alloy development for hydrogen-related technologies.

X-ray Absorption Fine Structure Spectroscopy (XAFS) has proven instrumental for the study of atomic-scale structures across diverse materials. This study conducts a meticulous comparative analysis between total electron yield (TEY) and absorption coefficients at the K absorption edge of polycrystalline Fe and Zr₆₀Cu₂₀Fe₂₀ alloy. Our findings not only highlight differences between TEY and transmission XAFS measurements but also demonstrate the capabilities and limitations inherent in these measurement modes within the context of XAFS. This article provides an experimental exploration of widely used X-ray absorption spectroscopy methods, shedding light on the nuances of TEY and transmission XAFS. Through presenting experimental results, we aim to offer insights crucial to the material science community, guiding experimentalists in optimizing measurements while raising awareness about potential misinterpretations.

TiVNbZrCr high-entropy intermetallic alloy was investigated as a deuterium storage material using gravimetric sorption measurements, thermogravimetric analysis, and temperature-resolved synchrotron X-ray diffraction during deuterium desorption. The as-prepared alloy had an experimentally determined composition of Ti₁₇V₁₉Zr₁₉Nb₂₂Cr₂₃ and a density of 6.59 g·cm⁻³. Empirical alloy-design parameters indicate that the alloy is not a single-phase bcc solid solution, but rather a compositionally complex intermetallic alloy. The calculated hydrogen-affinity descriptors suggest a strong thermodynamic driving force for deuteride formation. Under 5 MPa D₂, the alloy absorbed 3.28 wt.% D, corresponding to D/M = 1.1. After ex situ deuteration, additional diffraction reflections were indexed using tetragonal deuteride reference structures corresponding to ZrV₂D_2.35 and TiD₂, while the Cr-rich bcc phase remained comparatively stable. Thermal desorption released 2.28 wt.% D up to 600 °C in three partially overlapping steps. These results demonstrate that deuterium storage in TiVNbZrCr is governed by phase-selective deuteride formation and decomposition rather than by homogeneous bcc lattice expansion.

Medium-entropy alloys (MEAs) represent a promising class of materials for solid-state hydrogen storage due to their high hydrogen affinity, structural stability, and tunable properties. In this work, a compositional series of (TiZrNbTa)_{100−x}Al_x (x = 0–10 at. %) MEAs were prepared and systematically investigated to clarify the influence of aluminum addition on microstructure, mechanical response, and hydrogen sorption behavior. The alloys were synthesized by arc melting, homogenized by annealing, and characterized using microscopy, X-ray diffraction, density measurements, microhardness testing, nanoindentation, and hydrogen absorption/desorption experiments. Hydrogen sorption was evaluated by isobaric absorption measurements at 2 MPa H₂ over two consecutive cycles, complemented by thermogravimetric desorption analysis of hydrogenated samples. The results show that aluminum addition significantly affects activation behavior, hydrogen uptake, and residual hydrogen retention, while simultaneously increasing hardness and elastic modulus in a non-linear manner. The alloy containing 5 at. % Al exhibits the most balanced performance, combining reduced activation temperature in the second absorption cycle, relatively high hydrogen capacity, and moderate mechanical stiffness. These findings demonstrate that controlled aluminum alloying is an effective strategy for tailoring hydrogen–metal interactions and optimizing the performance of TiZrNbTa-based MEAs for solid-state hydrogen storage applications.