Stress corrosion cracking of 316L manufactured by laser powder bed fusion in 6% ferric chloride solution

Susceptibility to Pitting and Environmentally Assisted Cracking of 17-4PH Martensitic Stainless Steel Produced by Laser Beam Melting

“…Furthermore, small cracks were observed in a direction perpendicular to the mechanical loading axis (white arrow in Figure 7 b)). Cracks were initiated at pits, which was in agreement with the commonly accepted hypothesis that pits act as preferential crack initiation sites [ 37 , 38 , 39 , 40 , 41 , 42 , 49 ].…”

“…Calabrese et al [ 35 , 36 ] monitored the stress-corrosion cracking (SCC) process for 17-4PH MSS in a hot MgCl 2 solution by electrochemical noise and acoustic emission techniques; they showed that the corrosion mechanisms evolved from localised pitting to SCC. This was in good agreement with largely accepted conclusions that assumed pits were preferential sites for SCC initiation for SS [ 37 , 38 , 39 , 40 , 41 , 42 ]. Therefore, it could be assumed that differences in the austenite to martensite ratio, which have been related to various pitting behaviours, were likely to lead to changes in the EAC susceptibility of 17-4PH MSS; thus, differences in EAC susceptibility between L-PBF MSS and its conventional counterpart could be observed.…”

Revealing the stress corrosion cracking initiation mechanism of alloy 718 prepared by laser powder bed fusion assessed by microcapillary method

“…These findings are also in complete agreement with the authors' previous investigations on L-PBF 316 L austenitic stainless steels, identifying the impact of columnar subgrain width on localized corrosion susceptibility [51,52]. Moreover, in a recent study on SCC behaviour of L-PBF 316 L by Cruz et al [74], they indicated higher SCC resistance of L-PBF specimens compared to wrought counterparts as a result of significantly higher resistance of L-PBF specimens to pitting corrosion, leading to less possible active sites for crack initiation.…”

“…The same behaviour was observed in the authors' previous investigations on L-PBF processed 316 L austenitic stainless steel [51,52], revealing the selective dissolution of subgrains and subsequent mechanical rupture of the intact subgrain boundaries as the mechanism responsible for SCC propagation that was different from wrought counterparts [50]. Moreover, a recent investigation on SCC characteristics of L-PBF 316 L by Cruz et al [74] confirms the selective dissolution of subgrain observed in the current investigation, which is confirming the extent of such a phenomenon on austenitic microstructure of stainless steel alloys. Selective corrosion attack was also detected for conventional 718 on a wider scale adjacent to precipitates showing higher resistance of such phases to corrosion attack as shown previously in Fig.…”

Correlation of Lack of Fusion Pores with Stress Corrosion Cracking Susceptibility of L-PBF 316L: Effect of Surface Residual Stresses

“…Furthermore, Lou et al [ 25 ] investigated the effect of post-processing heat treatments on the SCC propagation behaviour of L-PBF 316L in a boiling water reactor (BWR) environment and indicated the importance of high-temperature heat treatments on SCC morphology. Moreover, a recent investigation by Cruz et al [ 26 ] on the SCC behaviour of L-PBF 316L, utilizing the slow strain rate method, confirmed cellular dissolution as the dominant mechanism in crack propagation. In the light of recent limited investigations on the SCC susceptibility of L-PBF-processed materials, concerns have been raised that call into question whether other types of defects present in MAM-processed components, such as LOF pores, could dramatically alter the SCC resistance of the material compared to the almost-full-density case.…”