Quantifying Void Formation and Changes to Microstructure During Hydrogen Charging: A Precursor to Embrittlement and Blistering

Influence of stress triaxiality on hydrogen assisted ductile damage in an X70 pipeline steel

“…Particularly, most HELP-based numerical models examine the effect of hydrogen on ductile damage, either on a single void through unit cell analysis [15, [17][18][19], or implicitly using adapted continuum models such as the Gurson model for void growth [20][21][22] or the fracture strain model [23]. Asadipoor et al [24] employed void observations from experimental studies [25,26] to motivate choices during their numerical calibration procedure for modelling tensile tests on hydrogen charged dual-phase steel. In HESIV-based numerical models, the mechanistic effect of hydrogen is incorporated through an increase of the void nucleation parameter [7].…”

“…In the context of hydrogen-void interactions, X-ray micro-CT was used by Morrissey et al [26] to analyze the effect of hydrogen charging in ferritic stainless steel, 125 without any mechanical loading. They observed an increase in initial void volume fraction due to hydrogen charging.…”

A finite element model to study the effect of porosity location on the elastic modulus of a cantilever beam

“…Throughout the life cycle of a structure, exposure to various environmental conditions, sometimes harsh, is possible. Due to these environmental conditions, it is possible that porosity can be increased in the material, as shown by Morrissey et al (2019). As such, structures may be affected in various locations, and in differing intensities, depending on the exposure to the environment.…”

“…Conversely, it was shown in Long et al (2017) through experiments that the process of annealing SAC305 solder healed microdefects to reduce the reduction in elastic modulus caused by porosity. As such, while a proper heat treatment can reduce the effect of porosity prior to environmental effects, it is still critical to quantify the effect of porosity and its location on a structure as evident from the results of Morrissey et al (2019).…”