Hydrogen Embrittlement in Inconel 718 Produced by Selective Laser Melting

2021 ◽  
Author(s):  
Giuseppe Macoretta ◽  
Marco Beghini ◽  
Bernardo Disma Monelli ◽  
Renzo Valentini ◽  
Francesco Aiello ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Hydrogen Diffusion ◽  
Mechanical Test ◽  
Tensile Tests ◽  
Material Strength ◽  
Hydrogen Effect ◽  
Laser Melting ◽  
Production Of Hydrogen

Abstract Inconel 718 is widely used to produce components subjected to relatively high temperatures and heavy loads. However, this alloy is also employed in aggressive environments promoting the production of hydrogen on the metal surface. Selective Laser Melting (SLM) is an emerging technology for the production of structural components, thanks to its ability to create complex geometries and reduce material consumption. Components produced by SLM are typically characterized by a peculiar microstructure and residual stresses that can affect hydrogen migration and accumulation. While the mechanical properties and fatigue endurance were deeply investigated in recent years, the resistance of SLMed Inconel 718 to the Hydrogen Embrittlement (HE) requires further investigation. The present paper deals with the effects of the SLM process on reducing the strength and ductility of Inconel 718. Standard tensile tests and slow strain rate tests were carried out for different hydrogen concentrations. Hydrogen content was measured in each specimen after the mechanical test. Fractographic analyses, along with hydrogen diffusion models, were carried out to preliminarily investigate the hydrogen effect on the material strength.

scholarly journals Hydrogen Embrittlement Behavior of 18Ni 300 Maraging Steel Produced by Selective Laser Melting

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2360 ◽  
Author(s):  
Young Jin Kwon ◽  
Riccardo Casati ◽  
Mauro Coduri ◽  
Maurizio Vedani ◽  
Chong Soo Lee
Keyword(s):  
Hydrogen Embrittlement ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Solution Treatment ◽  
Tensile Tests ◽  
Constant Current ◽  
Hydrogen Atoms ◽  
Laser Melting ◽  
Constant Current Density ◽  
Hydrogen Charging

A study was performed to investigate the hydrogen embrittlement behavior of 18-Ni 300 maraging steel produced by selective laser melting and subjected to different heat treatment strategies. Hydrogen was pre-charged into the tensile samples by an electro-chemical method at the constant current density of 1 A m−2 and 50 A m−2 for 48 h at room temperature. Charged and uncharged specimens were subjected to tensile tests and the hydrogen concentration was eventually analysed using quadrupole mass spectroscopy. After tensile tests, uncharged maraging samples showed fracture surfaces with dimples. Conversely, in H-charged alloys, quasi-cleavage mode fractures occurred. A lower concentration of trapped hydrogen atoms and higher elongation at fracture were measured in the H-charged samples that were subjected to solution treatment prior to hydrogen charging, compared to the as-built counterparts. Isothermal aging treatment performed at 460 °C for 8 h before hydrogen charging increased the concentration of trapped hydrogen, giving rise to higher hydrogen embrittlement susceptibility.

scholarly journals Investigation of Porosity and Mechanical Properties of Graphene Nanoplatelets-Reinforced AlSi10 Mg by Selective Laser Melting

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Shiqiang Lu ◽  
Weihan Xiao
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Quantitative Relationship ◽  
Tensile Tests ◽  
High Energy ◽  
Graphene Nanoplatelets ◽  
Material Strength ◽  
Strengthening Effect ◽  
Laser Melting ◽  
Composite Powders

Graphene possesses many outstanding properties, such as high strength and light weight, making it an ideal reinforcement for metal matrix composite (MMCs). Meanwhile, fabricating MMCs through laser-assisted additive manufacturing (LAAM) has attracted much attention in recent years due to the advantages of low waste, high precision, short production lead time, and high flexibility. In this study, graphene-reinforced aluminum alloy AlSi10 Mg is fabricated using selective laser melting (SLM), a typical LAAM technique. Composite powders are prepared using high-energy ball milling. Room temperature tensile tests are conducted to evaluate the mechanical properties. Scanning electron microscopy observations are conducted to investigate the microstructure and fracture surface of obtain composite. It is found that adding graphene nanoplatelets (GNPs) significantly increases porosity, which offsets the enhancement of tensile performance as a result of GNPs addition. Decoupling effort is then made to separate the potential beneficial effects from GNPs addition and the detrimental effect from porosity increase. For this purpose, the quantitative relationship between porosity and material strength is obtained. Taking into consideration the strength reduction caused by the increased porosity, the strengthening effect of GNPs turns out to be significant, which reaches 60.2 MPa.

Investigation of Porosity and Mechanical Properties of Graphene Nanoplatelets Reinforced AlSi10Mg by Selective Laser Melting

2017 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Shiqiang Lu ◽  
Weihan Xiao
Keyword(s):  
Selective Laser Melting ◽  
Tensile Tests ◽  
High Energy ◽  
Material Strength ◽  
Strengthening Effect ◽  
Laser Melting ◽  
Tensile Performance ◽  
Energy Ball ◽  
High Flexibility ◽  
The Relationship

Graphene possesses many outstanding properties, such as high strengths, light weight, making it an ideal reinforcement for metal matrix composite (MMCs). Meanwhile, fabricating MMCs through laser assisted additive manufacturing (LAAM) has attracted much attention in recent years due to the advantages of low waste, high precision, short production lead time, and high flexibility. In this study, graphene reinforced aluminum alloy AlSi10Mg is fabricated using selective laser melting. Composite powder is prepared using high-energy ball milling. Room temperature tensile tests are conducted to evaluate the tensile properties. Scanning electron microscopy (SEM) observations are conducted to investigate the microstructure and fracture surface of obtain composite. It is found that adding GNPs significantly increases porosity and therefore deteriorates material tensile performance. The relationship between porosity and material strength are numerically investigated. Taking into consideration the strength reduction caused by large porosity, the strengthening effect of GNPs turns out to be significant, which reaches 60.2 MPa.

scholarly journals Very-High-Cycle Fatigue Behavior of Inconel 718 Alloy Fabricated by Selective Laser Melting at Elevated Temperature

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1001
Author(s):  
Zongxian Song ◽  
Wenbin Gao ◽  
Dongpo Wang ◽  
Zhisheng Wu ◽  
Meifang Yan ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Selective Laser Melting ◽  
Fatigue Resistance ◽  
Inconel 718 ◽  
High Cycle Fatigue ◽  
Cycle Fatigue ◽  
Laser Melting ◽  
Inconel 718 Alloy ◽  
Very High Cycle Fatigue ◽  
Very High

This study investigates the very-high-cycle fatigue (VHCF) behavior at elevated temperature (650 °C) of the Inconel 718 alloy fabricated by selective laser melting (SLM). The results are compared with those of the wrought alloy. Large columnar grain with a cellular structure in the grain interior and Laves/δ phases precipitated along the grain boundaries were exhibited in the SLM alloy, while fine equiaxed grains were present in the wrought alloy. The elevated temperature had a minor effect on the fatigue resistance in the regime below 108 cycles for the SLM alloy but significantly reduced the fatigue strength in the VHCF regime above 108 cycles. Both the SLM and wrought specimens exhibited similar fatigue resistance in the fatigue life regime of fewer than 107–108 cycles at elevated temperature, and the surface initiation mechanism was dominant in both alloys. In a VHCF regime above 107–108 cycles at elevated temperature, the wrought material exhibited slightly better fatigue resistance than the SLM alloy. All fatigue cracks are initiated from the internal defects or the microstructure discontinuities. The precipitation of Laves and δ phases is examined after fatigue tests at high temperatures, and the effect of microstructure on the formation and the propagation of the microstructural small cracks is also discussed.

Influence of Heat Treatment on Microstructure and Mechanical Properties of Selective Laser Melted TiAl6V4 Alloy

2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Room Temperature ◽  
Base Alloy ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Treatment Procedures

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.

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