The Mechanism of the High Resistance to Hydrogen-Induced Strength Loss in Ultra-High Strength High-Entropy Alloy

The resistance of the Al0.5Cr0.9FeNi2.5V0.2 high-entropy alloy (HEA) to hydrogen embrittlement (HE) was investigated by a slow strain rate test (SSRT), and the fracture surface was examined through a scanning electron microscope. Compared with other high-strength steels, Al0.5Cr0.9FeNi2.5V0.2 showed insignificant strength loss after hydrogen charging. The fracture surface of the hydrogen-charged specimens mainly consisted of dimples, and no intergranular morphology was observed. The coupling effect of the dispersed nano-structured precipitates and high-density dislocations in Al0.5Cr0.9FeNi2.5V0.2 improves the resistance to hydrogen-induced strength loss.