Hydrogen embrittlement is a phenomenon where metals lose their ductility and load bearing capability due to the absorption of hydrogen, resulting in premature failure at stresses lower than the yield strength of the metal and severe damage to the employed components. This phenomenon is a crucial challenge affecting the safety, reliability and durability of engineering infrastructure used for the hydrogen value chain. Therefore, the prevention of hydrogen atom diffusion is one key consideration to avoid its adverse effects on materials' mechanical properties. Coating with diffusion barriers is a good approach to reduce hydrogen uptake in steels. This barriers can help preventing or delaying the entry of hydrogen into the material preserving favorable bulk attributes of the steel materials. Laser technology has been widely concerned because of its undeniable advantages such as high processing accuracy and easy automation. Laser processing makes it possible to modify the surface of any metallic material to generate different oxide layers that have been proven effective in reducing hydrogen damage.

In this work, the nanoindentation technique has been applied to evaluate how the hydrogen embrittlement phenomenon affects the surface mechanical properties of two austenitic stainless steels AISI 304L and 316L. Since nanoindentation is a simple and effective method for evaluating the mechanical response of films and coatings, this study has been extended to surfaces of the same steels modified by low energy laser surface modification, which have proven effective in reducing hydrogen damage. It is therefore noted that nanoindentation is a useful technique for evaluating damage caused by hydrogen and laser surface modification may be an effective tool to mitigate hydrogen permeation through the surface of structural materials.