Hydrogen induced slowdown of spallation in high entropy alloy under shock loading

Hydrogen embrittlement is ubiquitous in metals and alloys exposed to hydrogen, which has been extensively studied over a century. In contrast to traditional alloys, mechanisms of hydrogen embrittlement under shock loading are poorly understood, especially in recently emerging multiprinciple element and chemically disordered high entropy alloys (HEAs). By using a specially designed double-target technique, an unexpected phenomenon of hydrogen-retarded spallation was observed in CrMnFeCoNi HEA under plate impact loading. To reveal the underlying mechanism, a trans-scale statistical damage mechanics model was developed based on microstructural characterization and first principles calculations. The hydrogen-retarded nucleation of microvoids is attributed to hydrogen-vacancy complexes with high migration energy, while formation of nano-twins with high resistance reduces their growth rate. These results shed light on the better understanding of hydrogen embrittlement in chemically complex HEAs.

Automated summary

Hydrogen embrittlement in high entropy alloys (HEAs) was studied using a specially designed double-target technique, revealing the phenomenon of hydrogen-retarded spallation. A trans-scale statistical damage mechanics model was developed to explain the mechanism, attributing it to hydrogen-vacancy complexes and nano-twins. These results provide insights for a better understanding of hydrogen embrittlement in chemically complex HEAs.