Unveiling the role of indium and tin in Al–Ga based alloys for on-demand hydrogen supply from simulation to validation

Abstract

Al–Ga based alloys are important on-line hydrogen supply materials under harsh working conditions. Up to now, the activation mechanism is still unclear, especially the reason why In or Sn is indispensable to the alloys' performance is unknown. Here, we elaborately designed and implemented the simulation and validation experiments to unveil the role of indium and tin in the alloys. In simulation experiments, we conducted the penetration of liquid metals (LMs) into Al sheets to analyze its influence on Al's microstructure and the effects of In or Sn on Ga's distribution. We found that the activation effects of In and Sn are different. Subsequently, the validation experiments confirmed the above conclusion that In favors inducing deeper and wider cracks inside the alloy compared with Sn, thus making the alloy easier to break during hydrolysis and ensuring higher yields. Moreover, we found that Sn facilitated the reaction rate, which was explained by experiments and the theoretical calculation. Finally, a novel Al matrix embrittlement mechanism based on low-melting-point phases was proposed for Al–Ga based alloys, which provided a reference for the interpretation of material properties and precise material design. In addition, we gave suggestions for sample selection in actual working conditions.