# Dual-phase nano-glass-hydrides overcome the strength-ductility trade-off and magnetocaloric bottlenecks of rare earth based amorphous alloys

## TL;DR

Hydrogenation in metal alloys improves strength and ductility while enabling efficient magnetic refrigeration.

## Contribution

A dual-phase nano-glass-hydride structure is shown to enhance mechanical and magnetic properties of amorphous alloys.

## Key findings

- Hydrogen forms nano-sized ordered hydrides in a glassy shell, increasing yield strength by 44% and plastic strain to over 70%.
- The composite GdCoAlH exhibits a magnetic entropy change 105.5% larger than hydrogen-free samples.
- This combination overcomes limitations of amorphous alloys in magnetic refrigeration.

## Abstract

Metal-hydrogen systems have attracted intense interest for diverse energy-related applications. However, metals usually reduce their ductility after hydrogenation. Here, we show that hydrogen can take the form of nano-sized ordered hydrides (NOH) homogeneously dispersed in a stable glassy shell, leading to remarkable enhancement in both strength and ductility. The yield strength is enhanced by 44% and the plastic strain is substantially improved from almost zero to over 70%, which is attributed to the created NOH and their interplay with the glassy shell. Moreover, the hydride-glass composite GdCoAlH possesses a giant magnetic entropy change (−ΔSM) of 18.7 J kg−1K−1 under a field change of 5 T, which is 105.5% larger than the hydrogen-free sample and is the largest value among amorphous alloys and related composites. The prominent ΔSM-ductility combination overcomes the bottlenecks of amorphous alloys as magnetic refrigerants. These results provide a promising strategy for property breakthrough of structural-functional alloys.

Metals often suffer from reduced strength and ductility after hydrogenation. Here, the authors show hydrogenation can lead to enhancement in strength and ductility accompanied by a large change in magnetic entropy, overcoming the bottlenecks of using amorphous alloys for magnetic refrigerants.