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1

Influence of strain rate and temperature on the mechanical behaviour of additively manufactured AlSi10Mg alloy – experiment and the phenomenological constitutive modelling

Stanczak Magda, Rusinek Alexis, Broniszewska Paula, Fras Teresa, Pawłowski Piotr

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 4

art. no. e141983

EN

The paper is related to the material behaviour of additively manufactured samples obtained by the direct metal laser sintering (DMLS) method from the AlSi10Mg powder. The specimens are subjected to a quasi-static and dynamic compressive loading in a wide range of strain rates and temperatures to investigate the influence of the manufacturing process conditions on the material mechanical properties. For completeness, an analysis of their deformed microstructure is also performed. The obtained results prove the complexity of the material behaviour; therefore, a phenomenological model based on the modified Johnson–Cook approach is proposed. The developed model describes the material behaviour with much better accuracy than the classical constitutive function. The resulted experimental testing and its modelling present the potential of the discussed material and the manufacturing technology.

2

Analysis of direct metal laser sintering - DMLS and heat treatment influence on the Inconel 713C nickel alloy structure

Ciftci Jakub, Sitek Ryszard, Mizera Jarosław

Welding Technology Review

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2021

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R. 93, nr 3

49--56

EN

The group of nickel-based superalloys produced in the DMLS (Direct Metal Laser Sintering) process is limited to materials, which produced conventionally do not have properties to allow to use them for rotating components of aircraft engines. This work attempts to optimize the technological parameters of the DMLS process for the Inconel 713C nickel superalloy. A heat treatment was performed for selected samples to investigate the effect on the morphology of the Ni3Al phase. The microstructure analysis and hardness tests were carried out. The material after the DMLS process was characterized by the presence of much smaller dendrites than the cast material and exceeded its hardness. Additionally, for the tested variants of heat treatment, the material was characterized by smaller sizes of the Ni3Al phase by more than half. In order to ensure the stability of the microstructure, further optimization of the dedicated heat treatment after the DMLS process is required, as the standard heat treatment for Inconel 713C cast nickel superalloy does not fully recrystallize the material.

PL

Grupa nadstopów niklu wytwarzanych w procesie DMLS (ang. Direct Metal Laser Sintering) ogranicza się do materiałów, które wytwarzane konwencjonalnie nie posiadają właściwości, pozwalających zastosować je na elementy wirujące silników lotniczych. W pracy podjęto próbę optymalizacji parametrów technologicznych procesu DMLS dla nadstopu niklu Inconel 713C. Dla wybranych próbek przeprowadzono obróbkę cieplną w celu zbadania jej wpływu na morfologię fazy Ni3Al. Przeprowadzono analizę mikrostruktury oraz badania twardości. Materiał po procesie DMLS charakteryzował się obecnością znacznie mniejszych dendrytów niż materiał odlewany oraz przewyższał jego twardość. Dodatkowo dla zbadanych wariantów obróbki cieplnej materiał charakteryzował się mniejszymi rozmiarami fazy Ni3Al o ponad połowę. W celu zapewnienia stabilności mikrostruktury, wymagana jest dalsza optymalizacja obróbki cieplnej dedykowanej po procesie DMLS, ponieważ standardowa obróbka cieplna dla odlewanego nadstopu niklu Inconel 713C nie zapewnia pełnej rekrystalizacji materiału.

3

Analiza możliwości poprawy struktury stereometrycznej powierzchni elementów wykonanych w technologii DMLS

Palczak A.

Problemy Nauk Stosowanych

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2016

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T. 5

85--92

PL

Wstęp i cel: W artykule dokonano analizy struktury stereometrycznej powierzchni i opisano podjęte próby poprawy jej właściwości dla elementów wykonanych metodą wytwarzania przyrostowego. Materiał i metody: Przebadano strukturę stereometryczną powierzchni elementów wytworzonych poprzez selektywne spiekanie wiązką lasera sproszkowanej stali 316L. Podjęto również próbę poprawy parametrów powierzchni wytworzonych elementów poprzez obróbkę skrawaniem, szlifowanie, nagniatanie ślizgowe i toczne. Wyniki: W wyniku przeprowadzonych badań uzyskano znaczą poprawę parametrów względem powierzchni surowych, uzyskanych bezpośrednio w procesie wytwarzania przyrostowego. Jednocześnie parametry powierzchni uzyskanych konwencjonalnymi metodami nie różniły się w znaczący sposób. Wniosek: Warstwa wierzchnia elementów wykonanych metodą laserowego spiekania proszków metali cechuje się znaczną chropowatością. Dodatkowa obróbka tak wytworzonych detali poprzez zastosowanie konwencjonalnych metod takich jak skrawanie lub nagniatanie pozwala w istotny sposób zmniejszyć chropowatość.

EN

Introduction and aim: The article shows the analyze of the surface texture and describes attempts to improve surface parameters for the components made with the use of additive manufacturing technology. Material and methods: The surface texture of the elements made of powdered 316L stainless steel with the use of direct metal laser sintering technology were studied. Also an attempt was made to improve the parameters of the surface of those elements by machining or grinding and after that by roller or slide burnishing. Results: During the studies a significant improvement was achieved, relative to the surface parameters obtained directly in the DMLS process. Surface parameters obtained by conventional methods did not differ significantly. Conclusion: The outer layer of elements made out of metal powders with the laser sintering technology is characterized by a high roughness. Additional mechanical treatment of these parts with the use of conventional methods like turning or grinding and than roller or slide burnishing can significantly reduce the roughness.

4

Zastosowanie technologii CAD/CAM w stomatologii odtwórczej : przegląd piśmiennictwa

Bębenek K., Błaszczyk A., Kiryk J., Kotowski D., Kowalska K., Szczygielski T., Mazgajczyk E., Szymczyk P., Badora G., Bryła E., Dobrzyński M., Rybak Z.

Inżynier i Fizyk Medyczny

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2016

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Vol. 5, nr 2

99--104

PL

Technologia CAD/CAM, obejmująca komputerowe wspomaganie projektowania CAD (Computer-Aided Design) oraz komputerowe wspomaganie wytwarzania CAM (Computer-Aided Manufacturing), już przeszło dwie dekady jest stosowana w stomatologii odtwórczej. W tym okresie nastąpił znaczny rozwój systemów wspomagających kliniczną pracę lekarza dentysty, co wynika przede wszystkim z rosnącego zapotrzebowania na coraz bardziej precyzyjne i wysoce estetyczne prace protetyczne, możliwe do wykonywania w jak najkrótszym czasie. Systemy wykorzystujące technologię CAD/CAM stanowią alternatywę dla tradycyjnych i czasochłonnych metod laboratoryjnych, tj. techniki traconego wosku, odlewnictwa z użyciem metalicznych stopów czy pokrywania ceramiką dentystyczną. Zaspokojenie wysokich wymagań pacjentów związanych z estetyką uzupełnień protetycznych uwarunkowane jest dostępnościąmateriałów niezbędnych do ich wykonania. Dlatego wciąż poszukuje się materiałów o jak najkorzystniejszych właściwościach fizykochemicznych oraz doskonałej estetyce przy jednoczesnym zachowaniu biokompatybilności. Pierwsze uzupełnienie protetyczne z użyciem systemu CAD/CAM zostało wykonane na początku lat osiemdziesiątych ubiegłego stulecia. Początkowo system ten wykorzystywano w wytwarzaniu m.in. koron, licówek, nakładów czy wkładów. Dynamiczny rozwój materiałoznawstwa, jak i samej technologii CAD/CAM umożliwił wykonywanie wielopunktowych mostów protetycznych oraz łączników bądź diagnostycznych szablonów implantologicznych.

EN

CAD/CAM technology, including computer aided design (CAD) and computer-aided manufacturing (CAM) more than two decades in restorative dentistry is used. Within this period, a significant development of systems has been observed to support the clinical work of a dentist. It is primarily due to the growing demand for increasingly precise and highly aesthetic prosthetic restorations as well as their quick performance. Systems using CAD/CAM technology constitute an alternative to traditional and time-consuming laboratory methods, ie. techniques of lost wax, molding using metallic alloys or dental ceramics coverage. Satisfying the high requirements of patients associated with aesthetic restorations results from the availability of materials necessary for their performance. Therefore, we continue to look for the materials with good physical and chemical properties as well as excellent aesthetics while maintaining biocompatibility. The first restoration using CAD/CAM system was made in the early eighties of the previous century. At the beginning, the system was used in the preparation i.e. crowns, veneers, onlays or cartridges. The dynamic development of dental materials and the CAD/CAM technology, allowed to perform multipoint bridges and prosthetic fittings or implant diagnostic templates.

5

Characteristics of Products Made of 17-4PH Steel by means of 3D Printing Method

Walczak M., Gąska D., Guzik M.

Applied Computer Science

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2016

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Vol. 12, no 3

29--36

EN

The article presents the results of tests of 17-4PH steel fabricated by means of the method consisting in laser additive manufacturing (LAM) – direct metal laser sintering (DMLS). This grade of steel is characterized by excellent stress corrosion resistance in the first place and is applied as construction material in chemical, aircraft, medical or mould making industry. 3D metal printing is a relatively new method enabling significant change of structural properties of these materials at printing parameters predetermined by printers manufacturer for ”offline” printing mode. In order to achieve this goal, the authors have carried out the analysis of chemical composition, SEM tests and the tests of products surface rough-ness. Furthermore the products have been subjected to X-ray analysis by means of computed tomography (X-ray CT). Structural discontinuities have been found in upper layer and inside printouts subjected to tests.

6

Microstructural and micromechanical tests of titanium biomaterials intended for prosthetic reconstructions

Ryniewicz A. M., Bojko Ł., Ryniewicz W. I.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 1

121--127

EN

Purpose: The aim of the present paper was a question of structural identification and evaluation of strength parameters of Titanium (Ticp – grade 2) and its alloy (Ti6Al4V) which are used to serve as a base for those permanent prosthetic supplements which are later manufactured employing CAD/CAM systems. Methods: Microstructural tests of Ticp and Ti6Al4V were conducted using an optical microscope as well as a scanning microscope. Hardness was measured with the Vickers method. Micromechanical properties of samples: microhardness and Young’s modulus value, were measured with the Oliver and Pharr method. Results: Based on studies using optical microscopy it was observed that the Ticp from the milling technology had a single phase, granular microstructure. The Ti64 alloy had a two-phase, fine-grained microstructure with an acicular-lamellar character. The results of scanning tests show that titanium Ticp had a single phase structure. On its grain there was visible acicular martensite. The structure of the two phase Ti64 alloy consists of a β matrix as well as released α phase deposits in the shape of extended needles. Micromechanical tests demonstrated that the alloy of Ti64 in both methods showed twice as high the microhardness as Ticp. In studies of Young’s modulus of Ti64 alloy DMLS technology have lower value than titanium milling technology. Conclusions: According to the results obtained, the following conclusion has been drawn: when strength aspect is discussed, the DMLS method is a preferred one in manufacturing load structures in dentistry and may be an alternate way for the CAD/CAM system used in decrement processing.

7

Process optimization variables for direct metal laser sintering

Mierzejewska Ż. A.

Advances in Materials Science

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2015

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Vol. 15, nr 4(46)

38--51

EN

Manufacturing is crucial to creation of wealth and provision of quality of life. Manufacturing covers numerous aspects from systems design and organization, technology and logistics, operational planning and control. The study of manufacturing technology is usually classified into conventional and non-conventional processes. As it is well known, the term "rapid prototyping" refers to a number of different but related technologies that can be used for building very complex physical models and prototype parts directly from 3D CAD model. Among these technologies are selective laser sintering (SLS) and direct metal laser sintering (DMLS). RP technologies can use wide range of materials which gives possibility for their application in different fields. RP has primary been developed for manufacturing industry in order to speed up the development of new products (prototypes, concept models, form, fit, and function testing, tooling patterns, final products - direct parts). Sintering is a term in the field of powder metallurgy and describes a process which takes place under a certain pressure and temperature over a period of time. During sintering particles of a powder material are bound together in a mold to a solid part. In selective laser sintering the crucial elements pressure and time are obsolete and the powder particles are only heated for a short period of time. SLS uses the fact that every physical system tends to achieve a condition of minimum energy. In the case of powder the partially melted particles aim to minimize their in comparison to a solid block of material enormous surface area through fusing their outer skins. Like all generative manufacturing processes laser sintering gains the geometrical information out of a 3D CAD model. This model is subdivided into slices or layers of a certain layer thickness. Following this is a revolving process which consists of three basic process steps: recoating, exposure, and lowering of the build platform until the part is finished completely.

8

Material and Thermal Analysis of Laser Sintered Products

Hudák R., Šarik M., Dadej R., Živčák J., Harachová D.

Acta Mechanica et Automatica

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2013

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Vol. 7, no. 1

15-19

EN

Thermal analysis of laser processes can be used to predict thermal stresses and consequently deformation in a completed part. Analysis of temperature is also the basic for feedback of laser processing parameters in manufacturing. The quality of laser sintered parts greatly depends on proper selection of the input processing parameters, material properties and support creation. In order to relatively big heat stress in the built part during sintering process, the thermal simulation and thermal analysis, which could help better understand and solve the issue of parts deformations is very important. Main aim of presented work is to prepare input parameters for thermal simulations by the use of RadTherm software (Thermoanalytics Inc., USA), directly during the sintering process and after the process and find out the impact of the heat stress on a final shape and size of the prototype. Subsequently, an annealing process of constructed products after DMLS could be simulated and specified.

9

Wykonywanie elementów metalowych metodą DMLS

Wyszyński D., Chuchro M.

Mechanik

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2009

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R. 82, nr 11

946-946