scholarly journals Influence of Selective Laser Melting Technological Parameters on the Mechanical Properties of Additively Manufactured Elements Using 316L Austenitic Steel

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1449 ◽  
Author(s):  
Janusz Kluczyński ◽  
Lucjan Śnieżek ◽  
Krzysztof Grzelak ◽  
Jacek Janiszewski ◽  
Paweł Płatek ◽  
...  
Keyword(s):  
Energy Density ◽  
Selective Laser Melting ◽  
Dynamic Testing ◽  
Positive Impact ◽  
Image Correlation ◽  
Material Strength ◽  
Compression Tests ◽  
Dynamic Tests ◽  
Technological Parameters ◽  
Laser Melting

The main aim of this study was to investigate the influence of different energy density values used for the additively manufactured elements using selective laser melting (SLM).The group of process parameters considered was selected from the first-stage parameters identified in preliminary research. Samples manufactured using three different sets of parameter values were subjected to static tensile and compression tests. The samples were also subjected to dynamic Split–Hopkinson tests. To verify the microstructural changes after the dynamic tests, microstructural analyses were conducted. Additionally, the element deformation during the tensile tests was analyzed using digital image correlation (DIC). To analyze the influence of the selected parameters and verify the layered structure of the manufactured elements, sclerometer scratch hardness tests were carried out on each sample. Based on the research results, it was possible to observe the porosity growth mechanism and its influence on the material strength (including static and dynamic tests). Parameters modifications that caused 20% lower energy density, as well as elongation of the elements during tensile testing, decreased twice, which was strictly connected with porosity growth. An increase of energy density, by almost three times, caused a significant reduction of force fluctuations differences between both tested surfaces (parallel and perpendicular to the building platform) during sclerometer hardness testing. That kind of phenomenon had been taken into account in the microstructure investigations before and after dynamic testing, where it had been spotted as a positive impact on material deformations based on fused material formation after SLM processing.

scholarly journals Influence of Selective Laser Melting Technological Parameters on the Mechanical Properties of Additively Manufactured Elements Using 316L Austenitic Steel

2020 ◽  
Author(s):  
Janusz Kluczyński ◽  
Lucjan Śnieżek ◽  
Krzysztof Grzelak ◽  
Jacek Janiszewski ◽  
Paweł Płatek ◽  
...  
Keyword(s):  
Energy Density ◽  
Selective Laser Melting ◽  
Dynamic Testing ◽  
Positive Impact ◽  
Image Correlation ◽  
Material Strength ◽  
Compression Tests ◽  
Dynamic Tests ◽  
Technological Parameters ◽  
Laser Melting

The main aim of this study is to investigate the optimization of the technological process for selective laser melting (SLM) additive manufacturing. The group of process parameters considered was selected from the first-stage parameters identified in preliminary research. Samples manufactured using three different sets of parameter values were subjected to static tensile and compression tests. The samples were also subjected to dynamic Split–Hopkinson tests. To verify the microstructural changes after the dynamic tests, microstructural analyses were conducted. Additionally, the element deformation during the tensile tests was analyzed using digital image correlation (DIC). To analyze the influence of the selected parameters and verify the layered structure of the manufactured elements, sclerometer scratch hardness tests were carried out on each sample. Basing on the research results it was possible to observe the porosity growth mechanism and its influence on the material strength (including static and dynamic tests). Parameters modifications that caused 20% lower energy density, elongation of the elements during tensile testing decreased twice, which was strictly connected with porosity growth. An increase of energy density by almost three times caused a significant reduction of force fluctuations differences between both tested surfaces (parallel and perpendicular to the building platform) during sclerometer hardness testing. That kind of phenomenon had been taken into account in the microstructure investigations before and after dynamic testing where it had been spotted a positive impact on material deformations based on fused material grains formation after SLM processing.

scholarly journals Investigation of the Possibility of Tailoring the Chemical Composition of the NiTi Alloy by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1470
Author(s):  
Evgenii Borisov ◽  
Kirill Starikov ◽  
Anatoly Popovich ◽  
Tatiana Tihonovskaya
Keyword(s):  
Energy Density ◽  
Selective Laser Melting ◽  
Laser Processing ◽  
Niti Alloy ◽  
Nickel Content ◽  
Energy Parameter ◽  
High Energy ◽  
Single Treatment ◽  
Technological Parameters ◽  
Laser Melting

In this work a study of the selective laser melting process of two NiTi alloys of equiatomic, and rich Ni composition were conducted. A study of the influence of the technological parameters on the alloy density was carried out. Values of technological parameters were obtained to ensure production of samples with the lowest number of defects. When using process parameters with the same energy density but different values of the constituent technological parameters, the amount of nickel carried away by evaporation changed insignificantly. An increase in the energy density led to an increase in the amount of nickel carried away, causing final samples with lower Ni content. When using multiple laser processing in the low-energy parameter set, it was possible to achieve a decrease in the nickel content in the alloy, similar to that with single high-energy processing. DSC studies showed a significant increase in transformation temperatures upon repeated laser processing due to the higher evaporation of nickel. The use of double laser treatment gave a decrease in the final density of the sample compared to a single treatment, but its value is still higher than when using a single treatment with a higher energy density.

Main Defects Observed in Titanium GRADE II and 316L Stainless Steel Elements Obtained by Selective Laser Melting

2020 ◽  
Vol 308 ◽  
pp. 33-50
Author(s):  
Anna Woźniak ◽  
Marcin Adamiak
Keyword(s):  
Stainless Steel ◽  
Energy Density ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Defect Formation ◽  
Pure Titanium ◽  
Parameters Optimization ◽  
Laser Melting ◽  
Grade Ii ◽  
Titanium Grade

Selective Laser Melting SLM is one of the most popular three dimensional printing methods, which can be used for manufactured real elements (with high geometrical complexity) in many application, such as medicine, automotive or aerospace industries. The SLM final parts are characterized by high mechanical properties and satisfactory physicochemical properties. However, the properties of parts depend of process parameters optimization. In this paper, effects of processing parameters, such as laser power P, scanning speed SP, layer thickness t or point distance PD on defect formation and relative densities of manufactured elements are explored. For the purpose the stainless steel 316L and pure titanium Grade II are used. The process optimization were carried out according to the formula of energy density, which is delivered to the powder material. The stainless steel samples were divided into 12 groups, depends of the energy density. The titanium parts were printed at the same value of energy, and the process parameters are changed. The microscope observation and relative density measurements were carried out. Based on the obtained results, it can be confuted that the SLM parameters have a significant effect on the samples properties and the mechanism formed defect in both material are similar.

Influence of specimen size on the mechanical properties of microlattices obtained by selective laser melting

2019 ◽  
pp. 095440621986974
Author(s):  
Matteo Gavazzoni ◽  
Laura Boniotti ◽  
Stefano Foletti
Keyword(s):  
Elastic Modulus ◽  
Selective Laser Melting ◽  
Test Procedure ◽  
Specimen Size ◽  
The Body ◽  
Image Correlation ◽  
Good Prediction ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Laser Melting

A detailed study of compression tests on lattice structures obtained by selective laser melting with AlSi7Mg powder is presented here. Two different cell topologies have been investigated: the body-centered cubic cell and the face centered cubic cell or 3D Warren structure. Specimens of different volume have been printed in order to investigate the effect of the size on the mechanical response and properties of the structure. Particular attention has been paid to the definition of the test procedure and the analysis of the data to properly characterize the microlattice. No remarkable effect of the specimen size has been found in terms of elastic modulus and yielding stress. On the contrary, the maximum stress and the failure mechanism are influenced by the size of the specimen; for the body-centered cubic cell, a detailed analysis has been performed through digital image correlation of the failure. Test results have been compared with the results of an elasto-plastic simulation performed on a single cell of lattice with periodic boundary conditions, showing a good prediction in terms of elastic modulus and yielding stress.

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.

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