Hydrogen is considered a clean and efficient energy carrier crucial for shaping the net-zero future. Large-scale production, transportation, storage, and use of green hydrogen are expected to be undertaken in the coming decades. As the smallest element in the universe, however, hydrogen can adsorb on, diffuse into, and interact with many metallic materials, degrading their mechanical properties. This multifaceted phenomenon is generically categorized as hydrogen embrittlement (HE). HE is one of the most complex material problems that arises as an outcome of the intricate interplay across specific spatial and temporal scales between the mechanical driving force and the material resistance fingerprinted by the microstructures and subsequently weakened by the presence of hydrogen. Based on recent developments in the field as well as our collective understanding, this Review is devoted to treating HE as a whole and providing a constructive and systematic discussion on hydrogen entry, diffusion, trapping, hydrogen-microstructure interaction mechanisms, and consequences of HE in steels, nickel alloys, and aluminum alloys used for energy transport and storage. HE in emerging material systems, such as high entropy alloys and additively manufactured materials, is also discussed. Priority has been particularly given to these less understood aspects. Combining perspectives of materials chemistry, materials science, mechanics, and artificial intelligence, this Review aspires to present a comprehensive and impartial viewpoint on the existing knowledge and conclude with our forecasts of various paths forward meant to fuel the exploration of future research regarding hydrogen-induced material challenges.

Hydrogen diffusion and uptake in nickel Alloy 625 under cathodic protection potential (−1050 mV_Ag/AgCl) and temperature (10 °C) were studied using electrochemical permeation tests. It is the first time hydrogen permeation of nickel alloy at a temperature lower than room temperature was investigated. The results revealed that the effective diffusivity of hydrogen $D_{\text{eff}}$ at −1050 mV_Ag/AgCl varied from 1.81 to 2.86 × 10⁻¹⁵ m²/s across the temperature range of 10–23 °C. The effective subsurface hydrogen concentration $C_{sub}$ was influenced by both the applied temperature and overpotential. Particularly, the change in $C_{\text{sub}}$ at 10 °C is dependent on the hydrogen absorption efficiency affected by the surface coverage fraction of hydrogen. Furthermore, the hydrogen fugacity on the sample surface $f_{{\mathrm{H}}_2}$, the applied overpotential, and the temperature have been successfully cross correlated to interpret hydrogen evolution and adsorption. It was demonstrated that $f_{{\mathrm{H}}_2}$ primarily changed with the applied overpotential, while the temperature affected the gradient of $f_{{\mathrm{H}}_2}$ during the potential increment. The current study provides valuable insights for industries, assisting in the prediction of hydrogen absorption and hydrogen-assisted failures in subsea nickel alloy components.

In the present work, in situ electrochemical nanoindentation was utilized to investigate the hydrogen effect on the nanomechanical properties of tensile pre-strained nickel alloy (0%, 5% and 20%). The study reveals that hydrogen-induced hardening occurs during cathodic polarization due to hydrogen incorporation and softening behavior during anodic polarization; this is due to the irreversible microstructure modification induced in the presence of hydrogen solutes. Their respective contributions were quantified by fitting the elastoplastic part of the load-displacement data. In addition, the differences in their plastic behaviors were investigated in detail by examining the dislocation structure underneath the indents. This study aims to shed light on hydrogen’s interaction with pre-existing defects.

In order to solve the vibration problem of mining equipment, a Simulink simulation model of current loop, speed loop and position loop of permanent magnet synchronous motor was established to track the input position signal of the motor system.[1] At the same time, the input shaper is introduced into the motor three loop control model to study the vibration suppression effect of the input shaper.[2] The essence of the input shaper is to filter the input signal. Usually, the parameters of the input shaper need to be accurately identified and the detailed parameters of the system need to be identified. However, the problem that the identification accuracy of the system is not enough often makes the parameters of the shaper uncertain. In view of the problem that the system identification is not accurate, a method of adjusting and setting input shaper parameters is designed, which is not very dependent on the system. The results show that the optimal parameters of the shaper can be selected by the method. Compared with the parameters of the shaper selected according to the identification model, the vibration suppression effect is better.