Researchers have discovered that chemical short-range order (CSRO) in CoNiV high-entropy alloys (HEAs) plays a crucial role in regulating hydrogen energetics and its interaction with dislocations. This finding is significant because hydrogen embrittlement is a major problem in many metallic materials, and understanding how hydrogen behaves at the atomic level is fundamental for developing more resistant alloys. Traditionally, much attention has been paid to overall composition and crystal structure, but this study highlights the importance of local atomic arrangement.

The team used a combination of first-principles simulations based on density functional theory (DFT) and transmission electron microscopy (TEM) experiments to investigate CoNiV alloys. Simulations revealed that CSRO can significantly modify the preferential occupation sites for hydrogen within the crystal lattice, as well as the energetic barriers for its diffusion. Experimentally, it was observed that the presence of CSRO influences the formation of hydrogen Cottrell atmospheres around dislocations, which directly affects their mobility and, consequently, the material's ductility.

The results show that a specific CSRO can stabilize hydrogen in certain sites, reducing its tendency to accumulate at dislocation tips and thus mitigating embrittlement. Conversely, a different CSRO could exacerbate this problem. This control over hydrogen-dislocation interaction through CSRO engineering opens new avenues for designing more robust HEAs resistant to hydrogen embrittlement, with potential applications in industries such as aerospace or energy, where material reliability is critical.