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1

Thermal Operating Window in Selective Laser Melting Processes

Kozak Jerzy, Zakrzewski Tomasz, Witt Marta, Dębowska-Wąsak Martyna

Transactions on Aerospace Research

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2023

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Nr 4 (273)

18--32

EN

Selective laser melting (SLM) is one of the most effective methods of additive manufacturing (AM). It is used to manufacture products with very complex geometries using a wide range of materials. Practical process conditions are limited by the occurrence of undesirable melting instabilities that degrade the surface quality and lead to product defects. These disadvantages are related to the thermal limitations of the SLM process. The lower thermal limit is due to the need to completely melt the powder layer and partially remelt the underlying layer again to ensure proper bonding between the layers. Exceeding the upper thermal limit in the molten metal pool may cause extensive evaporation, boiling and ejection of molten metal droplets outside the melting area. The article presents an approach and methodology that enable the determination of thermal limits and the operating window of SLM/selective laser sintering (SLS) processes in a relatively simple way. The studies have been performed using various settings of SLM process parameters. The usefulness of the preliminary determination of thermal limitations and approximate prediction of operating window of SLM has been confirmed experimentally and by more accurate computer simulation.

2

Dynamic Behaviour of Selective Laser Melted 316L Steel : Mechanical Properties and Microstructure Changes

Białobrzewski Paweł, Sienkiewicz Judyta, Janiszewski Jacek, Kluczyński Janusz

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2023

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Vol. 14, Nr 2 (52)

51--72

EN

316L steel specimens with three different shear zones made by SLM (Selective Laser Melting) were subjected to dynamic tests using the Split Hopkinson Pressure Bar method. The effect of high-speed deformation on changes in microstructure was analyzed. In addition, the stress-strain relationship was determined from the SHPB results. To visualize the deformation process of the specimens during the tests, a camera with a high frame rate was used. It was shown that as the plastic deformation increases, the hardness of the material increases. Microstructural analysis of dynamically loaded areas revealed numerous defects. Twinning was found to be the main deformation mechanism. Large plastic deformation and many other microstructural changes such as shear bands, cracks and martensite nucleation were also observed.

PL

Próbki ze stali 316L z trzema różnymi strefami ścinania wykonane metodą SLM (Selective Laser Melting) poddano testom dynamicznym wykorzystując do tego metodę dzielonego pręta Hopkinsona (Split Hopkinson Pressure Bar). Przeanalizowano wpływ odkształceń o dużej szybkości na zmiany w mikrostrukturze. Ponadto na podstawie wyników badań SHPB wyznaczono zależność naprężenie- odkształcenie. W celu zobrazowania procesu odkształcania próbek podczas badań zastosowano kamerę o dużej częstości klatkowania. Wykazano, że wraz ze wzrostem odkształcenia plastycznego wzrasta twardość materiału. Analiza mikrostrukturalna obszarów obciążonych dynamicznie ujawniła liczne defekty. Stwierdzono, że głównym mechanizmem deformacji jest bliźniakowanie. Zaobserwowano również duże odkształcenia plastyczne i wiele innych zmian mikrostruktury, takich jak pasma ścinania, pęknięcia i zarodkowanie martenzytu.

3

High Temperature Oxidation Property of Ni Based Superalloy CM247LC Produced Via Selective Laser Melting Process

Lee Jung-Uk, Kim Young-Kyun, Seo Seong-Moon, Lee Kee-Ahn

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

107--112

EN

CM247LC alloy was manufactured by using selective laser melting (SLM) process, one of the laser powder bed fusion (L-PBF) methods. The hot isostatic pressing (HIP) process was additionally conducted on the SLM-built CM247LC to control its microstructures and defects. The high temperature oxidation property was investigated, and it was compared with conventional DS247LC sample (reference) prepared via the directional solidification process. The L-PBF HIP sample showed blocky-type MC carbides generated along the grain boundary with average size of about 200 nm. A semi-spherical primary γ' phase of size 0.4-1.0 μm was also observed inside the grains. Moreover, the DS247LC sample displayed a coarse eutectic γ' phase and many script-type MC carbides. Furthermore, cuboidal-type γ' with an average size of about 0.5 μm was detected. High-temperature oxidation tests were conducted at 1000°C and 1100°C for 24 hours. The results at 1100°C oxidation temperature showed that the measured oxidation weight gains for HIP and DS247LC were 1.96 mg/cm2 and 2.26 mg/cm2, respectively, indicating the superior high-temperature oxidation resistance of the L-PBF HIP sample. Based on the above results, a high-temperature oxidation mechanism of the CM247LC alloys manufactured by the SLM process and the directional solidification process has been proposed.

4

Process parameters effect on porosity rate of AlSi10Mg parts additively manufactured by Selective Laser Melting: challenges and research opportunities

Kiass E. M., Zarbane K., Beidouri Z.

Archives of Materials Science and Engineering

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2023

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Vol. 122, nr 1

22--33

EN

Purpose: The present study aims to conduct a literature review on the various methods explored to enhance the quality of AlSi10Mg parts manufactured via the Selective Laser Melting (SLM) process. Specifically, the research focuses on identifying strategies for reducing the porosity level in SLM-fabricated AlSi10Mg parts. Considering the highly competitive nature of the market in which SLM technology is employed, improving part quality is necessary to ensure business continuity and maintain a competitive edge. Design/methodology/approach: The present study offers a comprehensive examination of the SLM process, particularly emphasising the diverse parameters that can influence the porosity rate in SLM-fabricated parts. By providing a detailed description of the SLM process, we highlight the intricacy of this technology and discuss the significance of various parameters. Furthermore, we present a literature review of prior research on SLM, summarising the studied parameters and their impact on porosity. This research aims to enhance our understanding of the SLM process and the parameters that affect the density of SLM-fabricated parts. Findings: The present study aims to identify research opportunities in the field of SLM technology. One particularly promising area of investigation is exploring the correlation between scan direction and the porosity rate in SLM-fabricated parts. This research seeks to enhance our understanding of the relationship between these two parameters and their potential impact on the quality of SLM-fabricated parts. Practical implications: By reducing porosity, industries such as aerospace and aeronautics can attain enhanced performance through mechanical system optimisation. Originality/value: The present study summarises the various methods previously investigated for reducing the porosity rate in parts manufactured using the SLM process. Additionally, it proposes new avenues for achieving further parameter optimisation to attain higher levels of quality.

5

Nano-level mechanical and tribological behavior of additively manufactured AlSi10Mg plates

Murugesan Periyakaruppan, Satheeshkumar V., Jeyaprakash N., Prabu G., Yang Che-Hua

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e62, 2023

EN

This work focuses on the study of the selective laser melting (SLM) fabrication parameter of AlSi10Mg specimen. SLM parameters such as Power and scanning speed are varied to identify the defect-free samples. In addition, X-ray diffraction (XRD) analysis is carried out on the AM AlSi10Mg specimen to study the presence of phase. The results reveal that the Al matrix possesses (200), (220) and (311) phases whereas the AlSil0Mg powder has (111), (200), (220) and (311) phases. The microstructural characterization based on FESEM, TEM and EBSD analysis is carried out. The cross-section of the molten pool appears as a semi-cylindrical shape in the section that is parallel to the plane of powder deposition. The height, width and depth of the molten pool are measured as 150 ± 10 μm, 450 ± 10 μm and 50 ± 10 μm, respectively. TEM analysis reveals that the Si-precipitate and the eutectic Si element of the AM AlSi10Mg specimen are clearly formed in the AM AlSi10Mg specimen. Si precipitate spread within the grains whereas, the eutectic Si element is present at the grain boundary of the specimen. Then, the nanohardness and nanowear behavior are analyzed. Further, the influence of strain rate on the tensile strength is investigated. These mechanical tests are carried out on the defect-free AM AlSi10Mg specimen to assess its maximum performance. Very rough as well as irregular fracture surfaces are observed in the tensile test AM AlSi10Mg specimen. In addition to it, its magnified image reveals that the specimen fracture in the form of river patterns and contains a lot of micron-sized pores throughout the fracture surfaces.

6

Microstructure and mechanical properties of 3D-printed dental Co-Cr alloys, produced with the use of selective laser melting

Cherneva Sabina, Petrunov Vladimir, Petkov Vladimir, Bogdanov Vladimir, Simeonova Silviya

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 2

29--40

EN

The aim of present work was to investigate microstructure and mechanical properties of 3D printed by selective laser melting (SLM) Co-Cr alloys, intended for additive manufacturing in dentistry. Methods: A scanning electron microscope (SEM), equipped with an integrated Energy-Dispersive X-Ray Spectroscopy (EDS) system was used for investigation of the surface morphology and elemental composition of the 3D-printed Co-Cr sample. The X-ray structural analysis of the 3D-printed Co-Cr sample was made with a Bruker D8 Advance powder X-ray diffractometer. An atomic force microscopy (AFM) was used to investigate the surface topography of the sample. Tensile test, a three-point bending test and nanoindentation experiments were conducted for investigation of mechanical properties of the 3D-printed Co-Cr sample. The influence of two different strain rates (1 mm/min and 60 mm/min) on the flexural strength was investigated as well. Results: Higher values of indentation hardness (6.76 GPa), tensile strength (1016 MPa), yield strength (636.5 MPa) and flexural strength (1908 and 1891 MPa) of the Co-Cr alloys produced with the use of selective laser melting have been obtained, compared to cast Co-Cr and Cr-Ni alloys. It was found that increasing the strain rate from 1 mm/min to 60 mm/min caused a proportional decrease in recorded flexural strength of ~0.9%. Conclusions: The obtained results showed that the laser-sintered Co-Cr alloy can fully replace the cast Co-Cr alloy in dentistry, regarding its good mechanics properties as well as the high precision of the final product.

7

Microstructure and mechanical properties of selective laser melted 18Ni300 steel

Liang Yan, Qing Luo, Yu He, Huili Zhao, Yuxin Wang

Materials Science Poland

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2022

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Vol. 40, No. 3

64--71

EN

The energy transfer process of selective laser melting (SLM) is highly complex. In this work, experiments were carried out to study the effects of SLM on the microstructure and mechanical properties of 18Ni300 martensitic steel. With the increase in laser power, the grain size of the cladding layer decreases and the microstructure becomes dense. The side hardness is higher than upper surface hardness, and the tensile strength and elongation both increase first and then decrease. When the laser power is 300 W and the scanning speed is 1,000 mm/s, the comprehensive mechanical properties are the best, as the tensile strength, microhardness, elongation at break, and elongation after fracture are 1,217 MPa, 37.5%, 37.6%, and 8.93%, respectively. EBSD (Electron Backscatter Diffraction) shows that columnar crystals grow along the growth direction (z direction) in XOZ and YOZ planes, and the grains show weak texture. There are many small-angle grain boundaries, and the grain sizes are <10 μm.

8

Microplasma spraying of hydroxyapatite coatings on additive manufacturing titanium implants with trabecular structures

Kadyroldina Albina, Alontseva Dayra, Voinarovych Sergey, Łatka Leszek, Kyslytsia Oleksandr, Azamatov Bagdat, Khozhanov Aleksandr, Prokhorenkova Nadezhda, Zhilkashinova Almira, Burburska Svitlana

Materials Science Poland

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2022

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Vol. 40, No. 4

28--42

EN

This paper presents new results of microplasma spraying (MPS) of laboratory-synthesized hydroxyapatite (HA) powder coatings onto trabecular substrates obtained by selective laser melting (SLM) of a certified titanium medical alloy powder. The aim of the study was to establish the possibility of combining the technologies of MPS and additive manufacturing (AM) for the possible production of custom-designed implants with increased surface biocompatibility, as well as to establish the MPS parameters that ensure chemical purity of the HA coating and satisfactory adhesion of the coatings to the substrate. The structural-phase compositions of the initial HA powder and the plasma-sprayed HA coating were studied by X-ray diffraction analysis and transmission electron microscopy, and the adhesion strength of the coating was tested according to the F1147 standard of the American Society for Testing and Materials (ASTM). The main results of the study are the following: the application of the MPS technology for HA coating with an average thickness of 150±50 μm on trabecular substrates obtained by the SLM method has been shown. The parameters of MPS of HA coatings onto titanium implants with a trabecular surface have been established. It is also proved that using the appropriate MPS parameters, it is possible to obtain a HA coating with a 95% level of HA phases, 93% level of crystallinity, and the adhesion strength to the trabecular substrate of 24.7±5.7 MPa, which complies with the requirements of the international medical standard (International Organization for Standardization [ISO] 13779-2:2018). These results are of significance for a wide range of researchers developing plasma spray technologies for the manufacture of biocompatible coatings.

9

In-situ metal matrix composites development for additive manufacturing: a perspective

Essien U. A., Vaudreuil S.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 111, nr 2

78--85

EN

Purpose: This paper presents an overview on some ceramic materials capable of achieving in-situ reinforcements in Al/Al-alloy metal matrix composites (MMCs) during laser processing. It also presents perspective on further exploitation of the in-situ reinforcement capabilities for high quality MMCs feedstock material development. Design/methodology/approach: The approach utilized in writing this paper encompasses the review of relevant literature on additive manufacturing (AM) of MMCs. Findings: It is widely accepted that the in-situ reinforcement approach has proven to be more advantageous than the ex-situ approach. Though there are still some challenges like the formation of detremental phases and the evaporation of low melting temperature elements, the in-situ reinforcement approach can be used to tailor design composite powder feedstock materials for the AM of MMCs. The preprocessing or tailor-designing in-situ metal matrix composite powder before laser melting into desired components holds more promises for metal additive manufacturing. Practical implications: The need for the development of MMCs powder feedstock that can be directly fabricated using suitable AM technique without prior powder processing like blending or mechanical alloying has not yet been addressed Therefore, having a pre-processed in-situ reinforced MMC feedstock powder can encourage easy fabrication of MMC and other advantages of AM technologies powder recycling. Originality/value: The idea explained in this article is relevant to materials development for AM processing of metal matrix composite. This paper has pointed out future trends for MMCs materials feedstock powder development and new ideas for further exploitation of MMCs and AM technologies. The advantages of tailor-designing composite powders other than merely mixing them has been emphasized.

10

Zastosowanie techniki SLM na wykrojniki blach

Benedyk Marcin, Król Mariusz, Tański Tomasz

Stal, Metale & Nowe Technologie

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2021

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nr 11-12

16--22

PL

Jedną z technik druku 3D, dzięki której można wytworzyć metodą przyrostową niemalże lite elementy metalowe, jest metoda laserowego przetapiania proszków SLM (ang. selective laser melting). Jest to nowoczesna technologia pozwalająca na tworzenie elementów, które znajdują zastosowanie w obszarach począwszy od przemysłu motoryzacyjnego i lotniczego, a skończywszy na przemyśle stomatologicznym czy medycznym [1-3].

EN

One of the 3D printing technologies thanks to which almost solid metal elements can be produced using the additive method is SLM (selective laser melting). This is a modern technology that enables creating elements which are used in areas ranging from the automotive and aviation industry to the dental or medical industry [1-3].

11

Use of Selective Laser Melting (SLM) as a Replacement for Pressure Die Casting Technology for the Production of Automotive Casting

Piekło J., Garbacz-Klempka A.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 2

9--16

EN

Selective laser melting is one of the additive manufacturing technologies that is used to produce complex-shaped components for applications in the automotive industry. The purpose of the changes in the design, technology, and material tests was to make a steering gear housing using the SLM method. The steering gear housing was produced by the pressure casting method using an AlSi9Cu3(Fe) alloy. The construction of this housing is adapted to the specifics of left-hand traffic. The change in technology was related to the change of the position of the steering system from right-hand to left-hand and the demand for a limited number of gear housings. It was necessary to make a virtual model of the housing on the basis of the part that was removed from the vehicle. In SLM technology, the AlSi10Mg aluminum alloy was used as a raw material in the form of CL 32Al gas-atomized powder. After the SLM process was completed, the housings were subjected to heat treatment. The AlSi10Mg alloy fabricated by the SLM method after heat treatment is characterized by good plasticity and an average value of tensile strength. The last stage was to check the geometry of the SLM housing with a 3D scanner. As a result, a map of the dimensional deviations from the nominal values was obtained. This data was used to modify the CAD model before the next fabrication process. The use of 3D printing technology allowed for the quick production of elements. The time to develop the technology and the production of the first two gear housings based on a 3D model was seven days.

12

Microstructure and mechanical properties of Titanium grade 23 produced by selective laser melting

Nikiel Piotr, Wróbel Mirosław, Szczepanik Stefan, Stępień Michał, Wierzbanowski Krzysztof, Baczmański Andrzej

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 4

294--309

EN

Selective laser melted Titanium grade 23 was characterized by low porosity, relatively large surface roughness and pronounced surface texture (i.e. surface grooves orientation). The band/layer microstructure was built of mixed α and β phases. The as printed structure exhibited very high compressive residual stresses with strong anisotropy (i.e., − 512 ± 17 MPa and − 282 ± 14 MPa along the laser scanning direction and along the transverse direction, respectively) and strong fiber crystallographic texture. The latter one is responsible for the anisotropy of hardness in the material. Annealing at 600 °C during four hours significantly removed residual stresses (i.e. to − 14 ± 2.8 MPa) and slightly weakened the texture. Yield strength, 1120 ± 50 MPa, and ultimate tensile strength, 1210 ± 50 MPa, of the annealed material are significantly higher and tensile elongation, 3.9%, lower than for commercial Titanium grade 23. Final mechanical polishing to obtain flat and relatively smooth surface induced desired compression residual stress in the subsurface (i.e., equal to about − 90 MPa). Low absorbed gas contents (oxygen, nitrogen, hydrogen) and low porosity of the printed material indicates the correctness of the technology and allows the printed material to be classified as meeting the requirements of ASTM standards for Titanium grade 23. Besides traditional testing techniques, the optical profilometry, X-ray analysis (texture and residual stresses measurement) and infrared absorption method were applied for the product characterization and some potential of these testing methods and usefulness in technological practice was discussed, what can be particularly interesting both to practitioners from industry and researches from scientific laboratories.

13

Effects of equal channel angular pressing and heat treatments on the microstructures and mechanical properties of selective laser melted and cast AlSi10Mg alloys

Snopiński Przemysław, Król Mariusz, Pagáč Marek, Petrů Jana, Hajnyš Jiří, Mikuszewski Tomasz, Tański Tomasz

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

77--94

EN

This study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.

14

Wytwarzanie materiałów porowatych z proszku stopu Ti6Al4V w procesie selektywnego topienia laserowego

Gaweł Tomasz G.

LAB Laboratoria, Aparatura, Badania

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2020

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R. 25, nr 3

24--27

15

Optimization of the structure of titanium scaffolds reproducing the concellous bone

Skalski Konstanty, Filipowski Ryszard

Inżynieria Powierzchni

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2020

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nr 3-4

5--12

EN

The paper presents the scopes of examination of the cancellous bone, 3D CAD design of scaffolds of the cancellous bone and their creation with a laser beam in SLM incremental technology. The geometrical size of the scaffold and the material feature corresponding to the Young's modulus are the parameters describing the porous structure of the cancellous bone. In the statistical analysis, these values are defined as independent variables. The physical properties of the scaffold are defined by the strength parameters determined by hardness (e.g. HIT, HM, HV and are dependent variables). The REGMULT multiple regression program was used to develop the research results. However, to optimize the porous structure of the scaffold, the single-criteria optimization program SYEQL3 was used.

PL

W pracy przedstawiono zakresy badania kości gąbczastej, projektowania 3D CAD rusztowań (skaffoldów) kości gąbczastej oraz ich tworzenia wiązką lasera w technologii przyrostowej SLM. Parametrami opisującymi porowatą strukturą kości gąbczastej są: wielkości geometryczne rusztowania oraz cecha materiałowa odpowiadająca modułowi Younga. Wielkości te w analizie statystycznej definiowane są jako zmienne niezależne Własności fizykalne rusztowania zdefiniowane przez parametry wytrzymałościowe (twardości, np. HIT, HM, HV) są zmiennymi zależnymi. Do opracowania wyników badań zastosowano program regresji wielokrotnej o nazwie REGMULT. Do optymalizacji struktury porowatej skaffoldu, wykorzystano program optymalizacji jednokryterialnej SYEQL3.

16

Residual stress distribution in Cu-4.3%Sn alloys fabricated by selective laser melting (SLM)

Bunsch Adam, Ventura Anthony P., Cunningham Ross, Misiolek Wojciech Z.

Inżynieria Materiałowa

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2020

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Vol. 41, nr 1

10--17

EN

This paper is focused on the investigations of the residual stresses present in SLM Cu-4.3%Sn alloys, which were fabricated by the SLM process. The source Cu-4.3%Sn powder was analyzed for basic characteristics, and then the residual stress state was determined for 3D printed samples with different geometries before and after heat treatments. Stress measurements were performed using the X-ray diffraction ꞷ-sin2ψ method. Nonhomogeneous residual stresses were found to be present within SLM Cu-4.3%Sn alloys samples. Biaxial tensile stress was revealed in the interior of as-printed cube samples and it was reduced by annealing, whereas thin strip samples contained biaxial compressive stresses and after annealing the stress became more equi-biaxial but it was not reduced to zero near the sample surface. The results suggest how residual stresses are distributed within the copper SLM alloys with a simple shape. More complex geometries are expected to have correspondingly more complicated stress states. The performed investigation provides insight in to the residual stress distribution in copper alloys fabricated via SLM, which have not been widely studied yet. Application of the ꞷ-sin2ψ technique to the SLM process was analyzed and it was found that the methodology of utilizing the ꞷ-sin2ψ can be widely applied using standard X-ray diffraction facilities to study residual stresses within the additively manufactured metal alloy parts.

PL

Celem pracy było ustalenie stanu naprężeń własnych w stopach Cu-4,3%Sn wytwarzanych metodą selektywnego stapiania laserowego (SLM). Wyniki pomiaru naprężeń zostały skorelowane z uprzednio zmierzonymi właściwościami mechanicznymi i mikrostrukturą. W ramach pracy oceniono, czy zastosowany proszek ze stopu Cu-4,3%Sn spełnia oczekiwania stawiane materiałom na wyroby uzyskiwane techniką SLM oraz sprawdzono, czy metoda dyfrakcyjna ꞷ-sin2ψ jest odpowiednią metodą do pomiarów naprężeń szczątkowych w wyrobach ze stopu miedzi wykonanych metodą SLM.

17

Effect of Post-Heat Treatment on the Wear Properties of AlSi10Mg Alloy Manufactured by Selective Laser Melting

Park Tae-Hyun, Baek Min-Seok, Sohn Yongho, Lee Kee-Ahn

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 3

1073--1080

EN

Microstructure and wear property of AlSi10Mg alloy manufactured by selective laser melting (SLM) were investigated. Also, the effect of post heat treatment on the mechanical and wear properties was examined. Two kinds of heat treatments (direct aging (DA) and T6) were separately conducted to SLM AlSi10Mg alloy. As-built alloy had a cellular structure formed inside the moltenpool. Eutectic Si was also observed at the cellular boundary in as-built alloy. After DA heat treatment, the cellular structure still remained, and a large amount of nano-size Si particles were newly formed inside the cell structure. Both molten pool and cellular structure disappeared, and the size of Si increased in T6 alloy. The values of Vickers hardness measured as 139.4 HV (DA alloy), 128.0 HV (As-built alloy) and 85.1 HV (T6 alloy), respectively. However, concerning to wear property, T6 alloy showed better wear resistance than other alloys. The correlation between microstructure and wear mechanism of SLM AlSi10Mg alloy was also discussed.

18

A comprehensive study of mechanical and acoustic properties of selective laser melting material

Barile Claudia, Casavola Caterina, Moramarco Vincenzo, Vimalathithan Paramsamy Kannan

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 1

30--40

EN

In this research work, four groups of selective laser melted specimens were built from AlSi10Mg-0403 powder. Each group represents the direction with respect to the bed in which the specimens are built (X, Y, Z and 45° orientation). The mechanical properties of the specimens are characterized in terms of yield strength, ultimate tensile strength, Young’s modulus and elongation at break. In addition to that, the acoustic emission (AE) during the testing was monitored using wide-band high-accuracy piezoelectric sensors. The AE results were related to the mechanical characteristics of the specimens in terms of the acoustic parameter-based data, the peak amplitude, cumulative energy and count rate. The mechanical results show that the specimens built along the z direction have relatively lower strength and it can be attributed to the borderline porosity formed during the SLM process. The acoustic results can identify the critical points of failure under loading. The AE technique proves to be a powerful tool in characterizing the mechanical property and can unveil the concealed information which cannot be identified directly from the mechanical results.

19

LASERTEC 30 SLM 2nd Gen. Produkcja przyrostowa metodą selektywnego stapiania laserowego (SLM)

Świat Obrabiarek i Narzędzi

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2019

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R. 14, nr 3-4

8

20

Structure, Texture and Tensile Properties of Ti6Al4V Produced by Selective Laser Melting

Konečná Radomila, Medvecká Denisa, Nicoletto Gianni

Production Engineering Archives

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2019

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Vol. 25

60--65

EN

Additive manufacturing has recently expanded its potential with the development of selective laser melting (SLM) of metallic powders. This study investigates the relation between the mechanical properties and the microstructure of Ti6Al4V alloy produced by SLM followed by a hot isostatic pressing (HIP) treatment. HIP treatment minimizes the detrimental influence of material defects. Tensile specimens produced with reference to specific building axes were prepared using a Renishaw A250 system. It has been found that the tensile strength and elongation depend on specimen building direction. Microstructural and textural characterizations were carried out to identify the source of differences.