Understanding the Interaction between a Steel Microstructure and Hydrogen

Abstract

The present work provides an overview of the work on the interaction between hydrogen (H) and the steel’s microstructure. Different techniques are used to evaluate the H-induced damage phenomena. The impact of H charging on multiphase high-strength steels, i.e., high-strength low-alloy (HSLA), transformation-induced plasticity (TRIP) and dual phase (DP) is first studied. The highest hydrogen embrittlement resistance is obtained for HSLA steel due to the presence of Ti- and Nb-based precipitates. Generic Fe-C lab-cast alloys consisting of a single phase, i.e., ferrite, bainite, pearlite or martensite, and with carbon contents of approximately 0, 0.2 and 0.4 wt %, are further considered to simplify the microstructure. Finally, the addition of carbides is investigated in lab-cast Fe-C-X alloys by adding a ternary carbide forming element to the Fe-C alloys. To understand the H/material interaction, a comparison of the available H trapping sites, the H pick-up level and the H diffusivity with the H-induced mechanical degradation or H-induced cracking is correlated with a thorough microstructural analysis.

Addressing H-Material Interaction in Fast Diffusion Materials—A Feasibility Study on a Complex Phase Steel

“…The effect of H on high-strength steels has been widely studied [ 5 , 6 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ], but there are few studies regarding the interaction between H and CP steels. Malitckii et al [ 32 ] investigated the role of retained austenite in CP steel and proposed that fatigue intergranular areas might be formed due to H accumulation at the austenite/martensite interfaces, followed by H-induced decohesion.…”

Thermal Desorption Spectra of H in an Fe–C–Nb Alloy Evaluated by Diffusion Simulation

“…The reason for this is that free H is able to relocate to already strained and damaged regions, e.g., the tip of a crack, where it can contribute to further damage of the respective region. [6] The effective mobility of H in a material can be influenced. A major way of doing so is by providing positions within the lattice that provide a lower energy site for the hydrogen atoms and, thus, introduce an energy barrier that needs to be overcome to enable further positional changes once an H atom has moved into such a trap (see Figure 1).…”

“…The reason for this is that free H is able to relocate to already strained and damaged regions, e.g., the tip of a crack, where it can contribute to further damage of the respective region. [ 6 ]…”

Hydrogen-enhanced fatigue crack growth behaviors in a ferritic Fe-3wt%Si steel studied by fractography and dislocation structure analysis

“…Steels are commonly used structural materials that may be affected by HE [15][16][17][18]. There are mainly two different crystal structures in steels, namely face-centered cubic (FCC) and bodycentered cubic (BCC).…”