Two and three-dimensional characterisation of localised corrosion affected by lack-of-fusion pores in 316L stainless steel produced by selective laser melting

Pitting corrosion of 17-4PH stainless steel manufactured by laser beam melting

“…8a and b, respectively) showed that there was no clear evidence of a relationship between the gas pores present in the LBM steel and the pit initiation. This was in agreement with Laleh et al who showed that the critical condition for pit initiation was not easily established for gas pores because they were open to the solution [45].…”

“…The differences in NbC size between the LBM and wrought samples could therefore have an influence on the stable pit initiation step, leading to differences in stable pit density between both LBM and wrought samples, and therefore, for a similar charge passed, to changes in the stable pit size. In a similar way, despite the very low amount of pores detected inside the LBM samples, those defects were also susceptible to affect the stable pit initiation process as shown in literature [44,45]. Therefore, it was of great interest to determine whether differences in pit density and/or size could be observed between wrought and LBM samples.…”

“…Nevertheless, the influence of those metallurgical parameters, in particular the austenite content, on the pitting resistance of LBM samples remained an unresolved issue that required much more detailed study. Furthermore, attention had to be paid to the influence of pores on the pitting behaviour of the LBM samples, many authors having demonstrated their detrimental effect on the pitting resistance [44,45]. However, in the present study, such an analysis was made very difficult due to the very low amount of pores.…”

“…On the contrary, lack-of-fusion pores, with a very irregular shape, could lead to occluded volume favourable to pit initiation [44,45]. Observations of a lack-of-fusion pore before (OM, Fig.…”

Revealing the growth kinetics of atmospheric corrosion pitting in aluminum via in situ microtomography

“…Both laboratory-based and synchrotron XCT have been used to study pit growth under immersed and atmospheric conditions, for galvanic couples and the evolution of environmentally-assisted cracking 2,[4][5][6][7][8][9][10][11][12][13][14][15] . Several recent studies utilized X-ray microtomography to directly measure the rate and morphology of intergranular corrosion of AA7075 and AA2024 during the initial stages of atmospheric corrosion under millimeter-sized chloride salt droplets 3,16,17 .…”