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

Yazdanpanah, Arshad; Franceschi, Mattia; Revilla, Reynier I.; Khademzadeh, Saeed; Graeve, Iris De; Dabalà, Manuele

doi:10.1016/j.corsci.2022.110642

Cited by 13 publications

(4 citation statements)

References 82 publications

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“…Such an increase in the acidity of the solution leads to the annihilation of the ability of the passive layer present in cavities to repassivate, leading to severe localized corrosion and/or SCC attack in such sites. What we observed in our recent investigations on the SCC initiation behaviour of L-PBF 718 nickel-iron-based superalloy [ 45 ], and also LPBF 316L under the short-range variation in energy input density [ 23 , 24 ], was that when the L-PBF-fabricated part was full density with small spherical pores, minor changes in pore size (by means of pore surface area) did not drastically change the corrosion behaviour. A recent study by Sander et al [ 31 , 46 ] also emphasized that even with an increase in chloride ion contamination level, small pores were not activating as active localized corrosion sites.…”

Section: Discussionmentioning

confidence: 72%

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

et al. 2022

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Stress corrosion cracking (SCC) of laser powder bed fusion-fabricated 316L was studied under the variation in energy input density to emulate the existence of distinctive types of defects. Various electrochemical polarization measurements were performed in as-received polished and ground states, to elucidate the effect of defect type on corrosion and SCC behaviour in marine solution. The results revealed severe localized corrosion attack and SCC initiation for specimens with a lack of fusion pores (LOF). Moreover, the morphology of SCC was different, highlighting a more dominant effect of selective dissolution of the subgrain matrix for gas porosities and a more pronounced effect of brittle fracture at laser track boundaries for the specimens with LOF pores.

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Section: Discussionmentioning

confidence: 72%

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

et al. 2022

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“…The unreacted metal surface acts as a passive-like film: that is, the result of a purely porous metallic film. This mechanism consistently creates layers, with diminutive fracture toughness, that have severely modified mechanical properties, causing many stress-corrosion cracking processes in alloys [ 36 , 37 , 38 , 39 , 40 ]. Dealloying was first established to deliver porous nickel, which is used as a catalyst in several chemical activities [ 41 , 42 , 43 , 44 ].…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Performance and Hydrogen Storage of Ni–Pd–P–B Glassy Alloy

et al. 2022

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The search for hydrogen storage materials is a challenging task. In this work, we tried to test metallic glass-based pseudocapacitive material for electrochemical hydrogen storage potential. An alloy ingot with an atomic composition of Ni60Pd20P16B4 was prepared via arc melting of extremely pure elements in an Ar environment. A ribbon sample with a width of 2 mm and a thickness of 20 mm was produced via melt spinning of the prepared ingot. Electrochemical dealloying of the ribbon sample was conducted in 1 M H2SO4 to prepare a nanoporous glassy alloy. The Brunauer–Emmett–Teller (BET) and Langmuir methods were implemented to obtain the total surface area of the nanoporous glassy alloy ribbon. The obtained values were 6.486 m2/g and 15.082 m2/g, respectively. The Dubinin–Astakhov (DA) method was used to calculate pore radius and pore volume; those values were 1.07 nm and 0.09 cm3/g, respectively. Cyclic voltammetry of the dealloyed samples revealed the pseudocapacitive nature of this alloy. Impedance of the dealloying sample was measured at different frequencies through use of electrochemical impedance spectroscopy (EIS). A Cole–Cole plot established a semicircle with a radius of ~6 Ω at higher frequency, indicating low interfacial charge-transfer resistance, and an almost vertical Warburg slope at lower frequency, indicating fast diffusion of ions to the electrode surface. Charge–discharge experiments were performed at different constant currents (75, 100, 125, 150, and 200 mA/g) under a cutoff potential of 2.25 V vs. Ag/AgCl electrode in a 1 M KOH solution. The calculated maximum storage capacity was 950 mAh/g. High-rate dischargeability (HRD) and capacity retention (Sn) for the dealloyed glassy alloy ribbon sample were evaluated. The calculated capacity retention rate at the 40th cycle was 97%, which reveals high stability.

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“…Porosity assessment was performed by optical microscopy (OM) using a LEICA DMRE optical microscope (Leica Microsystems S.r.l., Milan, Italy). With the aim of having a good statistical model for the pore characterization, 5 pictures were taken from each magnification of 50, 100, and 200× from both the center and surface of the cross-sectioned surface, according to the procedure reported by the authors in [9,10,60]. Subsequently, the images were analyzed with ImageJ 1.54d [61], and statistical analysis was performed utilizing the OriginLab 2023b software [62].…”

Section: L-pbf Fabrication and Parameter Optimizationmentioning

confidence: 99%

“…These techniques can be categorized into different groups [1], with laser powder bed fusion (L-PBF) being the most diffused method. Extensive research on L-PBF is available in the literature [5][6][7][8][9][10], highlighting its superior accuracy and the high quality of the final components it produces. L-PBF involves the deposition of layers of powders on a build platform and the subsequent melting, adopting a high-power laser beam.…”

Section: Introductionmentioning

confidence: 99%

Laser Powder Bed Fusion Fabrication of a Novel Carbide-Free Bainitic Steel: The Possibilities and a Comparative Study with the Conventional Alloy

Franceschi,

Yazdanpanah,

Leone

et al. 2024

Metals

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A newly developed medium-carbon carbide-free bainitic steel was fabricated for the first time utilizing the laser powder bed fusion (L-PBF) technique. Process parameters were optimized, and a high density of 99.8% was achieved. The impact of austempering heat treatment on the bainite morphology and transformation kinetics was investigated by high-resolution microstructural analysis (SEM, TEM, and EDS) and dilatometric analysis, and results were compared with conventionally produced counterparts. Faster kinetics and finer microstructures in the L-PBF specimens were found as a consequence of the as-built microstructure, characterized by fine grains and high dislocation density. However, a bimodal distribution of bainitic ferrite plate thickness (average value 60 nm and 200 nm, respectively) was found at prior melt pool boundaries resulting from carbon depletion at such sites.

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

Cited by 13 publications

References 82 publications

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

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

Electrochemical Performance and Hydrogen Storage of Ni–Pd–P–B Glassy Alloy

Laser Powder Bed Fusion Fabrication of a Novel Carbide-Free Bainitic Steel: The Possibilities and a Comparative Study with the Conventional Alloy

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