Which material is least likely to suffer hydrogen embrittlement?

• A. High-strength steels
• B. Some nickel alloys
• C. Titanium alloys
• D. Low-strength steels

Answer: (D)

Hydrogen embrittlement happens when hydrogen atoms diffuse into metal, especially under tensile stress, making the material more prone to brittle cracking. The tendency for this to occur rises with the metal’s strength and hardness because those conditions promote crack initiation and propagation at tiny defects or grain boundaries.

Low-strength steels have the lowest yield strength and are more ductile. That means they can deform more before cracking and don’t concentrate stress at cracks as easily, so hydrogen-assisted cracking is much less likely compared with stronger materials. In contrast, high-strength steels are well known for being highly susceptible, and some nickel and titanium alloys can also experience embrittlement under hydrogen exposure, depending on conditions.

So, among the options, the material least likely to suffer hydrogen embrittlement is the low-strength steel.