Study of Size Effect on Microstructure and Mechanical Properties of AlSi10Mg Samples Made by Selective Laser Melting

The macroscopic mechanical performance of additive manufactured structures is essential for the design and application of multiscale microlattice structure. Performance is affected by microstructure and geometrical imperfection, which are strongly influenced by the size of the struts in selective laser melting (SLM) lattice structures. In this paper, the effect of size on microstructure, geometrical imperfection, and mechanical properties was systemically studied by conducting experimental tests. A series of AlSi10Mg rod-shaped samples with various diameters were fabricated using SLM. The uniaxial tensile test results show that with the decrease in build diameter, strength and Young’s modulus of strut decreased by 30% more than the stable state. The main reasons for this degradation were investigated through microscopic observation and micro X-ray computed tomography (μ-CT). In contrast with large-sized strut, the inherent porosity (1.87%) and section geometrical deviation (3%) of ponysize strut is greater because of the effect of thermal transform and hydrogen evolution, and the grain size is 0.5 μm. The discrepancy in microstructure, geometrical imperfection, and mechanical properties induced by size effect should be considered for the design and evaluation of SLM-fabricated complex structures.

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

MRS Advances ◽

10.1557/adv.2019.251 ◽

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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The Influence of Sub-Zero Conditions on the Mechanical Properties of Polylactide-Based Composites

Materials ◽

10.3390/ma13245789 ◽

2020 ◽

Vol 13 (24) ◽

pp. 5789

Author(s):

Olga Mysiukiewicz ◽

Mateusz Barczewski ◽

Arkadiusz Kloziński

Keyword(s):

Mechanical Properties ◽

Room Temperature ◽

Mechanical Performance ◽

Mechanical Analysis ◽

Uniaxial Tensile ◽

Uniaxial Tensile Test ◽

Mechanical And Thermal Properties ◽

Scanning Calorimetry ◽

Linseed Cake ◽

Static Mechanical

Polylactide-based composites filled with waste fillers due to their sustainability are a subject of many current papers, in which their structural, mechanical, and thermal properties are evaluated. However, few studies focus on their behavior in low temperatures. In this paper, dynamic and quasi-static mechanical properties of polylactide-based composites filled with 10 wt% of linseed cake (a by-product of mechanical oil extraction from linseed) were evaluated at room temperature and at −40 °C by means of dynamic mechanical analysis (DMA), Charpy’s impact strength test and uniaxial tensile test. It was found that the effect of plasticization provided by the oil contained in the filler at room temperature is significantly reduced in sub-zero conditions due to solidification of the oil around −18 °C, as it was shown by differential scanning calorimetry (DSC) and DMA, but the overall mechanical performance of the polylactide-based composites was sufficient to enable their use in low-temperature applications.

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Microstructures and Mechanical Properties of Stainless Steel AISI 316L Processed by Selective Laser Melting

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.898 ◽

2014 ◽

Vol 783-786 ◽

pp. 898-903 ◽

Cited By ~ 38

Author(s):

Anne Mertens ◽

Sylvie Reginster ◽

Quentin Contrepois ◽

Thierry Dormal ◽

Olivier Lemaire ◽

...

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Selective Laser Melting ◽

Uniaxial Tensile ◽

Layer By Layer ◽

Aisi 316L ◽

Laser Melting ◽

Uniaxial Tensile Testing ◽

Steel Aisi ◽

Stainless Steel Aisi

In this study, samples of stainless steel AISI 316L have been processed by selective laser melting, a layer-by-layer near-net-shape process allowing for an economic production of complex parts. The resulting microstructures have been characterised in details in order to reach a better understanding of the solidification and consolidation processes. The influence of the processing parameters on the mechanical properties was investigated by means of uniaxial tensile testing performed on samples produced with different main orientations with respect to the building direction. A strong anisotropy of the mechanical behaviour was thus interpreted in relation with the microstructures and the processing conditions.

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Effects of Homogenization Heat Treatment on Mechanical Properties of Inconel 718 Sandwich Structures Manufactured by Selective Laser Melting

Metals ◽

10.3390/met10050645 ◽

2020 ◽

Vol 10 (5) ◽

pp. 645 ◽

Cited By ~ 2

Author(s):

Sebastian Marian Zaharia ◽

Lucia Antoneta Chicoș ◽

Camil Lancea ◽

Mihai Alin Pop

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Selective Laser Melting ◽

Inconel 718 ◽

Mechanical Performance ◽

Sandwich Structures ◽

Laser Melting ◽

Homogenization Heat Treatment ◽

Finite Element Analysis Simulation ◽

Before And After

In this study, lightweight sandwich structures with honeycomb cores are proposed and their mechanical properties are investigated through experiments and FEA (finite element analysis) simulation. Sandwich structures were fabricated out of Inconel 718 using selective laser melting technique with two different topologies—sandwich structures with perforated skin (SSPS) and sandwich structures with perforated core (SSPC). In addition, the effect of the homogenization heat treatment on the mechanical properties of the sandwich samples subjected to compression and microhardness tests was analyzed. Results showed significant increases of mechanical performance before and after homogenization heat treatment of the Inconel 718 samples. Microstructure analysis was performed to compare the microstructures before and after homogenization heat treatment for Inconel 718 alloys manufactured by selective laser melting (SLM). The accuracy of experimental data were evaluated by modeling of sandwich samples in Ansys software at the end of this study.

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Valuation of Mechanical Properties and Microstructural Characterization of ASTM F75 Co-Cr Alloy Obtained by Selective Laser Melting (SLM) and Casting Techniques

Materials Science Forum ◽

10.4028/www.scientific.net/msf.899.323 ◽

2017 ◽

Vol 899 ◽

pp. 323-328 ◽

Cited By ~ 1

Author(s):

Marcello Vertamatti Mergulhão ◽

Carlos Eduardo Podestá ◽

Maurício David Martins das Neves

Keyword(s):

Mechanical Properties ◽

Selective Laser Melting ◽

Rupture Strength ◽

Microstructural Characterization ◽

Tensile Yield Strength ◽

Uniaxial Tensile ◽

Laser Melting ◽

Standard Samples ◽

X Ray ◽

Astm F75

Advances in processes using the powder metallurgy techniques are making this technology competitive compared to the other traditional manufacturing processes, especially in medicine area. The additive rapid prototyping technique – selective laser melting (SLM) was applied in a biomaterial of CoCrMoFe alloy (ASTM F75), to study the mechanical properties and microstructural characterization in comparison between the conventional technique – casting. The gas atomized powder was investigated by their physical (as apparent density, bulk density and flow rate) and the chemical properties. The powder was analyzed using scanning electron microscope with energy-dispersed X-ray spectroscopy (SEM-EDS) and X-ray fluorescence. Specimens of standard samples were manufactured using these techniques to evaluate the mechanical properties as uniaxial tensile (yield strength, rupture tensile and elongation), transverse rupture strength and the micro hardness. The mechanical properties showed higher values in the SLM specimens than the casting specimens. Before the mechanical tests the specimens were examined using optical microscope (OM) and SEM-EDS. The micrographs revealed a microstructure with finer morphology in the SLM technique and the dendrites in the casting technique.

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A Further Analysis on Ti6Al4V Lattice Structures Manufactured by Selective Laser Melting

Journal of Healthcare Engineering ◽

10.1155/2019/3212594 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Saverio Maietta ◽

Antonio Gloria ◽

Giovanni Improta ◽

Maria Richetta ◽

Roberto De Santis ◽

...

Keyword(s):

Mechanical Properties ◽

Mass Transport ◽

Selective Laser Melting ◽

Mechanical Performance ◽

Stress Shielding ◽

Lattice Structures ◽

Laser Melting ◽

Tissue Ingrowth ◽

Architectural Features ◽

Bone Atrophy

Mechanical and architectural features play an important role in designing biomedical devices. The use of materials (i.e., Ti6Al4V) with Young’s modulus higher than those of natural tissues generally cause stress shielding effects, bone atrophy, and implant loosening. However, porous devices may be designed to reduce the implant stiffness and, consequently, to improve its stability by promoting tissue ingrowth. If porosity increases, mass transport properties, which are crucial for cell behavior and tissue ingrowth, increase, whereas mechanical properties decrease. As reported in the literature, it is always possible to tailor mass transport and mechanical properties of additively manufactured structures by varying the architectural features, as well as pore shape and size. Even though many studies have already been made on different porous structures with controlled morphology, the aim of current study was to provide only a further analysis on Ti6Al4V lattice structures manufactured by selective laser melting. Experimental and theoretical analyses also demonstrated the possibility to vary the architectural features, pore size, and geometry, without dramatically altering the mechanical performance of the structure.

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Effect of build orientation on the surface quality, microstructure and mechanical properties of selective laser melting 316L stainless steel

Rapid Prototyping Journal ◽

10.1108/rpj-04-2016-0068 ◽

2018 ◽

Vol 24 (1) ◽

pp. 9-17 ◽

Cited By ~ 35

Author(s):

Hamza Hassn Alsalla ◽

Christopher Smith ◽

Liang Hao

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Surface Quality ◽

Selective Laser Melting ◽

Process Parameters ◽

Mechanical Performance ◽

Laser Melting ◽

Content Type ◽

Microstructure And Mechanical Properties ◽

Conventional Material

Purpose The purpose of this paper is to investigate the density, surface quality, microstructure and mechanical properties of the components of the selective laser melting (SLM) parts made at different building orientations. SLM is an additive manufacturing technique for three-dimensional parts. The process parameters are known to affect the properties of the eventual part. In this study, process parameters were investigated in the building of 316L structures at a variety of building orientations and for which the fracture toughness was measured. Design/methodology/approach Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens. Optical and electron microscopy were used to characterise the microstructure of the SLM specimens and their effects on properties relating to fracture and the mechanics. It was found that the density of built samples is 96 per cent, and the hardness is similar in comparison to conventional material. Findings The highest fracture toughness value was found to be 176 MPa m^(1/2) in the oz. building direction, and the lowest value was 145 MPa m^(1/2) in the z building direction. This was due to pores and some cracks at the edge, which are slightly lower in comparison to a conventional product. The build direction does have an effect on the microstructure of parts, which subsequently has an effect upon their mechanical properties and surface quality. Dendritic grain structures were found in oz. samples due to the high temperature gradient, fast cooling rate and reduced porosity. The tensile properties of such parts were found to be better than those made from conventional material. Originality/value The relationship between the process parameters, microstructure, surface quality and toughness has not previously been reported.

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Mechanical Properties of Selective Laser-Melted Components of Alsi10mg for Prototype Vehicles

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.399 ◽

2021 ◽

Vol 1016 ◽

pp. 399-406

Author(s):

Christoph Egger ◽

Florian Grünbart ◽

Zahra Silvayeh ◽

Olga Šulcová ◽

Christoph Seper ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Selective Laser Melting ◽

Computer Aided Design ◽

Cast Alloy ◽

Hot Isostatic Pressing ◽

Tensile Tests ◽

Uniaxial Tensile ◽

Laser Melting ◽

Pressure Die Casting

Fabrication of aluminum alloy components by traditional high-pressure die casting (HPDC) requires cost- and time-consuming tooling of steel dies, which makes HPDC uneconomic for producing low-volume components or prototypes. In comparison, powder bed-based additive manufacturing, e.g. selective laser melting (SLM), enables rapid prototyping and production of even complex-shaped components directly from computer-aided design models without needing expensive tools. However, SLM prototype components must have almost identical mechanical properties to HPDC serial components in order to emulate their functionality under different load conditions. In this work uniaxial tensile properties of cast alloy AlSi10MnMg (EN AC-43500) in condition T7, i.e. with 120-170 MPa yield stress, 200-240 MPa tensile strength and 9-12 % strain at fracture, shall be attained using selective laser melting of powder alloy AlSi10Mg (EN AC-43000). These properties were achieved by tailored heat treatment. Furthermore, the effect of hot isostatic pressing (HIP) was investigated. The results of the tensile tests confirmed the basic feasibility of substituting HPDC components with SLM components for prototyping. In particular, similar tensile strength and uniform strain were achieved for SLM samples in condition O, i.e. for SLM samples which were only annealed.

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Effect of Zr content on crack formation and mechanical properties of IN738LC processed by selective laser melting

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(21)65582-6 ◽

2021 ◽

Vol 31 (5) ◽

pp. 1350-1362

Author(s):

Yong HU ◽

Xiao-kang YANG ◽

Wen-jiang KANG ◽

Yu-tian DING ◽

Jia-yu XU ◽

...

Keyword(s):

Mechanical Properties ◽

Selective Laser Melting ◽

Crack Formation ◽

Laser Melting

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Experimental and Numerical Evaluation of Mechanical Properties of 3D-Printed Stainless Steel 316L Lattice Structures

Journal of Materials Engineering and Performance ◽

10.1007/s11665-021-05737-w ◽

2021 ◽

Author(s):

M. Carraturo ◽

G. Alaimo ◽

S. Marconi ◽

E. Negrello ◽

E. Sgambitterra ◽

...

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Mechanical Behavior ◽

Numerical Simulations ◽

Uniaxial Tensile ◽

Uniaxial Tensile Test ◽

Lattice Structures ◽

Stainless Steel 316L ◽

Research Attention ◽

Octet Truss

AbstractAdditive manufacturing (AM), and in particular selective laser melting (SLM) technology, allows to produce structural components made of lattice structures. These kinds of structures have received a lot of research attention over recent years due to their capacity to generate easy-to-manufacture and lightweight components with enhanced mechanical properties. Despite a large amount of work available in the literature, the prediction of the mechanical behavior of lattice structures is still an open issue for researchers. Numerical simulations can help to better understand the mechanical behavior of such a kind of structure without undergoing long and expensive experimental campaigns. In this work, we compare numerical and experimental results of a uniaxial tensile test for stainless steel 316L octet-truss lattice specimen. Numerical simulations are based on both the nominal as-designed geometry and the as-build geometry obtained through the analysis of µ-CT images. We find that the use of the as-build geometry is fundamental for an accurate prediction of the mechanical behavior of lattice structures.

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