Microstructure design strategies to mitigate hydrogen embrittlement in metallic materials

Abstract

Hydrogen embrittlement (HE) is characterized by the sudden loss of a material's mechanical property due to the premature failure induced by the ingress of H atoms and various H‐materials interactions. This phenomenon threatens almost all the metallic materials that brings an abrupt halt to some of the pending infrastructures needed for a H economy. The development of microstructure design strategies to mitigate HE is challenging, as the fundamental mechanisms for HE process are still not well understood. Nevertheless, some progresses in this field have been made in recent years. Here, we provide an overview on established microstructural approaches to mitigate HE in metallic materials. These methods include second‐phase trapping, grain refinement, grain boundary engineering, solute segregation and heterogeneity, and surface treatment. Their effectiveness and materials applicability are compared. The operating mechanisms, advantages, and limitations of these approaches are also discussed to guide their future development and successful industrial application.

Hydrogen Embrittlement as a Conspicuous Material Challenge─Comprehensive Review and Future Directions

“…Reported alloying and microstructural strategies for such purpose include (a) the introduction of H-trapping second phases, (b) grain refinement, (c) GB engineering, (d) solute segregation and heterogeneity, and (e) surface treatment. 26,868,869 Here we only provide a brief overview on their operating principles, advantages and limitations; more detailed information can be found elsewhere. 868 Due to the interaction between H and certain types of second phases (e.g., V-, Ti-, and Nb-based carbides in steels), they can be used to trap H within the microstructure, thereby reducing the rate of H permeation as well as H diffusion within the material.…”

“…26,868,869 Here we only provide a brief overview on their operating principles, advantages and limitations; more detailed information can be found elsewhere. 868 Due to the interaction between H and certain types of second phases (e.g., V-, Ti-, and Nb-based carbides in steels), they can be used to trap H within the microstructure, thereby reducing the rate of H permeation as well as H diffusion within the material. This factor, in principle, will enhance alloys' HE resistance, regardless of the prevalent damage mechanisms.…”

“…This factor, in principle, will enhance alloys’ HE resistance, regardless of the prevalent damage mechanisms. However, the effect can become detrimental if the precipitate itself and the related hetero-interfaces are prone to H-induced cracking. ,,, On the other hand, the trapping effect of second-phases will essentially increase the uptake of H. This additional amount of H, if trapped not deeply enough, might become diffusible particularly under elevated temperatures, which can enhance the risks of HE. It should also be noted that the effectiveness of the second-phase trapping approach is highly dependent on the service environment of a material.…”

“…In addition to the aforementioned coating approach, one alternative is to design the composition and microstructure of the alloys to enable a more intrinsic resistance to HE. Reported alloying and microstructural strategies for such purpose include (a) the introduction of H-trapping second phases, (b) grain refinement, (c) GB engineering, (d) solute segregation and heterogeneity, and (e) surface treatment. ,, Here we only provide a brief overview on their operating principles, advantages and limitations; more detailed information can be found elsewhere …”

Guest editorial of virtual special issue: Structural integrity in the context of carbon neutrality

“…However, hydrogen embrittlement brings an abrupt halt to some of the pending infrastructures needed for an H economy. Sun et al 1 addressed five microstructural approaches to suppress hydrogen embrittlement in metallic materials, including second‐phase trapping, grain refinement, grain boundary engineering, solute segregation and heterogeneity, and surface treatment. The effectiveness, advantages and limitations of these methods are discussed.…”