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 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.

scholarly journals TiAl-Based Materials by In Situ Selective Laser Melting of Ti/Al Reactive Composites

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1505
Author(s):  
Andrey A. Nepapushev ◽  
Dmitry O. Moskovskikh ◽  
Ksenia V. Vorotilo ◽  
Alexander S. Rogachev
Keyword(s):  
Selective Laser Melting ◽  
High Energy ◽  
Composite Particles ◽  
Exothermic Effect ◽  
Laser Melting ◽  
Intermetallic Materials ◽  
Al Composite ◽  
High Laser ◽  
One Step ◽  
Energy Ball

Additive manufacturing (AM) of refractory materials requires either a high laser power or the use of various easily melting binders. In this work, we propose an alternative—the use of spherical reactive Ti/Al composite particles, obtained by preliminary high-energy ball milling. These powders were used to produce high-temperature TiAl-based materials during the selective laser melting (SLM) process. When laser heating is applied, mechanically activated composite particles readily react with the release of a considerable amount of heat and transform into corresponding intermetallic compounds. The combustion can be initiated at relatively low temperatures, and the exothermic effect prevents the sharp cooling of as-sintered tracks. This approach allows one to produce dense intermetallic materials with a homogeneous structure in one step via SLM and eliminates the need for powerful lasers, binders, or additional post-processing and heat treatments.

Production of Rounded Reactive Composite Ti/Al Powders for Selective Laser Melting by High-Energy Ball Milling

2019 ◽  
Vol 50 (3) ◽  
pp. 1241-1247 ◽  
Author(s):  
A. A. Nepapushev ◽  
D. O. Moskovskikh ◽  
V. S. Buinevich ◽  
S. G. Vadchenko ◽  
A. S. Rogachev
Keyword(s):  
Ball Milling ◽  
Selective Laser Melting ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Laser Melting ◽  
Energy Ball

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.

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.

Microhardness Enhancement in Fully Dense Fe-Based Nanophase Metallic Alloys

1995 ◽  
Vol 400 ◽  
Author(s):  
L. He ◽  
E. Ma
Keyword(s):  
Grain Size ◽  
High Energy ◽  
Metallic Alloys ◽  
Full Density ◽  
Strengthening Effect ◽  
Two Phase ◽  
Grain Sizes ◽  
Sinter Forging ◽  
Interphase Boundaries ◽  
Energy Ball

AbstractNano-grained Fe-29Al-2Cr intermetallic and Fe-Cu two-phase composites have been consolidated to full density from powders produced by high-energy ball milling, using a sinter forging procedure developed recently in our laboratory. Grain sizes remained within nanophase range (<100 nm) after consolidation. Microhardness tests of Fe-29Al-2Cr samples consolidated to different density levels indicate a significant strengthening effect due to nanoscale grain size and a monotonic microhardness increase with decreasing residual porosity. Fully dense Fe-Cu composites exhibit enhanced microhardness as compared with rule-of-mixtures predictions, which may be attributable to interface strengthening at fcc-bcc interphase boundaries.

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 Microstructure and mechanical properties relationship of additively manufactured 316L stainless steel by selective laser melting

2019 ◽  
Vol 5 ◽  
pp. 23 ◽  
Author(s):  
Anne-Helene Puichaud ◽  
Camille Flament ◽  
Aziz Chniouel ◽  
Fernando Lomello ◽  
Elodie Rouesne ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Industrial Applications ◽  
Added Value ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties

Additive manufacturing (AM) is rapidly expanding in many industrial applications because of the versatile possibilities of fast and complex fabrication of added value products. This manufacturing process would significantly reduce manufacturing time and development cost for nuclear components. However, the process leads to materials with complex microstructures, and their structural stability for nuclear application is still uncertain. This study focuses on 316L stainless steel fabricated by selective laser melting (SLM) in the context of nuclear application, and compares with a cold-rolled solution annealed 316L sample. The effect of heat treatment (HT) and hot isostatic pressing (HIP) on the microstructure and mechanical properties is discussed. It was found that after HT, the material microstructure remains mostly unchanged, while the HIP treatment removes the materials porosity, and partially re-crystallises the microstructure. Finally, the tensile tests showed excellent results, satisfying RCC-MR code requirements for all AM materials.

scholarly journals Microstructure and Mechanical Properties of 316L Stainless Steel Fabricated Using Selective Laser Melting

MRS Advances ◽  
2019 ◽  
Vol 4 (44-45) ◽  
pp. 2431-2439
Author(s):  
N. Iqbal ◽  
E. Jimenez-Melero ◽  
U. Ankalkhope ◽  
J. Lawrence
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
Laser Scanning ◽  
316L Stainless Steel ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Laser Melting ◽  
Sample Height

ABSTRACTThe microstructure homogeneity and variability in mechanical properties of 316L stainless steel components fabricated using selective laser melting (SLM) have been investigated. The crack free, 99.9% dense samples were made starting from SS316L alloy powder, and the melt pool morphology was analysed using optical and scanning electron microscopy. Extremely fast cooling rates after laser melting/solidification process, accompanied by slow diffusion of alloying elements, produced characteristic microstructures with colonies of cellular substructure inside grains, grown along the direction of the principal thermal gradient during laser scanning. In some areas of the microstructure, a significant number of precipitates were observed inside grains and at grain boundaries. Micro hardness measurements along the build direction revealed slight but gradual increase in hardness along the sample height. Uniaxial tensile tests of as manufactured samples showed the effect of un-melted areas causing scatter in room-temperature mechanical properties of samples extracted from the same SLM build. The ultimate tensile strength (UTS) varied from 458MPa to 509MPa along with a variation in uniform elongation from 3.3% to 14.4%. The UTS of a sample exposed to the Cl- rich corrosion environment at 46oC temperature revealed a similar strength as of the original sample, indicating good corrosion resistance of SLM samples under those corrosion conditions.

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