HE-resistant Materials Design
Tailoring precipitates for enhanced hydrogen trapping in aluminum alloys
Yucheng Ji, Xiaoqian Fu, Mahdieh Safyari, Chenyang Yao, Fei Shuang, Xucheng Yin, Xiaogang Li, Masoud Moshtaghi, Chaofang Dong, Poulumi Dey
Enhancing the hydrogen embrittlement (HE) resistance of alloys caters to the urgent needs of
engineering safety and long-distance hydrogen transportation. Highly dense precipitates present
in the microstructure of alloys act as H traps, however, some of them cannot strongly trap H
thus failing to prevent its accumulation at the critical regions (e.g., crack tip, etc) resulting
in the material’s rapid failure. Experimentally, it is challenging to expeditiously identify and
generate phases causing strengthening and acting as strong H traps. Here, we demonstrate a
computation-based design strategy to generate precipitates strongly trapping H, decreasing
the HE susceptibility of Al alloy (by ~78%) by tuning the Cu distribution in the microstructure.
Our density functional theory results show that the Cu-doped Al3Sc exhibit strong Cu-H bond.
The quantum machine learning Al-Sc-Cu potential, developed within this study, aids in rapidly
determining the optimal processing parameters to create phases that can strongly trap H
even though they are metastable in nature. Our modelling approach provides insights
into the underlying mechanisms behind precipitation. Elemental mapping in the electron
microscope confirms the presence of Cu in Al3Sc, which exhibits a more deeply trapped
H peak than dislocations in the H desorption curve. Hence, we envisage the proposed
strategy will accelerate the design of HE-resistant microstructures of various
technologically relevant materials via identification of desirable phases.