Effects of grain size and dislocation density on the susceptibility to high-pressure hydrogen environment embrittlement of high-strength low-alloy steels

Analysis of hydrogen permeation tests considering two different modelling approaches for grain boundary trapping in iron

“…in a fine-grained material, it is expected that local concentration in grain boundaries are lower. This effect was also confirmed by (Takasawa et al 2012) who also pointed out that grain refinement mitigate embrittlement due to the reduction of the slip length of dislocations. Competition between dislocation-boundary interaction and hydrogen effects should be better understood.…”

“…strain rate dependence of hydrogen embrittlement). However, as found by other authors, (Takasawa et al 2012;Park et al 2015;Macadre et al 2015), the grain refinement mitigation of embrittlement in Slow Strain Rate tests (SSRT) is expected to happen due to the redistribution of the same amount of hydrogen over a higher boundary surface so the local segregation and the subsequent intergranular decohesion is reduced.…”

Effects of grain size on hydrogen embrittlement in a Fe-22Mn-0.6C TWIP steel

“…Therefore, the material with finer grain size become less sensitive to the hydrogen embrittlement, which has been evidenced by both stress and strain loss analysis in the present study. The improvement in the resistance to hydrogen embrittlement by grain refinement has also been reported in high strength low alloy steel in gaseous hydrogen of 45 MPa [29,30] and in pure nickel [17,18].…”

“…Some work has already been done in studying the effect of grain size on the susceptibility of materials to hydrogenrelated failures [17,29e31]. The tensile properties of highstrength low-alloy steels in a hydrogen atmosphere were examined and it revealed that both grain refinement and a reduction in dislocation density were effective in reducing the susceptibility to HE [29,30]. The effect of grain size on the susceptibility of martensitic steels to hydrogen related failure has also been examined by means of slow strain-rate test and the results are in good agreement with previous ones [31].…”

The advantage of grain refinement in the hydrogen embrittlement of Fe–18Mn–0.6C twinning-induced plasticity steel

“…It has been reported that the resistance to HE was enhanced by grain refinement due to the reduction in the concentration of hydrogen segregated at grain boundaries [23][24][25][26] for high strength low alloy steels [23], Fe-Ni alloys [24], and duplex stainless steels [25]. However, in the case of TWIP steel, grain refinement increases not only the area of grain boundaries but also reduces the volume fraction of mechanical twins [5,6,27], which provide strong sites for hydrogen trapping [16,28,29] and crack formation [30].…”