scholarly journals Production of magnets from the material of Fe - Cr - Co system by selective laser sintering

2021 ◽  
Vol 64 (10) ◽  
pp. 721-727
Author(s):  
D. B. Efremov ◽  
A. A. Gerasimova

The article presents results of the study of possibilities of selective laser melting (SLM), or so-called additive technologies, for production of permanent magnets. This process makes it possible to produce not only product models and prototypes, but also finished functional products using layer-by-layer addition of material and binding of particles and layers to each other. An alloy based on Fe - Cr - Co system has been chosen as the material for evaluation of the compared technologies for permanent magnets production. The application fields of selective laser melting (SLM/SLP) were considered. The powders obtained by different methods are taken for the research. Classical technology of magnetic alloy casting also was analyzed. The studies of magnetic materials and comparisons of the properties of powder magnets with standard data were carried out. On the basis of 25Kh15KA alloy powder sprayed by gas atomization, permanent magnets with a material density of 7.59 - 7.55 g/cm3 can be manufactured at the SLP plant. They meet the requirements recommended by the state standard GOST 24897 - 81, and achieve characteristics of magnets made by classical metallurgical technologies. To study the magnetic and physical properties, four samples were produced with the same geometry in the shape of a cube. During production of each of the test samples, different operating modes of the plant were selected. Samples were made on the basis of the “Kurchatov Institute” NRS enterprise (the “Prometheus” Central Research Institute of Construction Materials) as part of the NIO-35 technological complex. It was established that characteristics of the powders obtained by gas atomization qualitatively exceed characteristics of the powders obtained by other methods, and the produced magnets meet all the requirements for magnets.

2021 ◽  
Vol 346 ◽  
pp. 01010
Author(s):  
Dmitry Efremov ◽  
Alla Gerasimova ◽  
Nikita Kislykh ◽  
Cristina Shaibel

The paper presents the results of studying the possibility of using the selective laser melting method for production of permanent magnets. This process allows to manufacture not only product models and prototypes, but also finished functional products by adding material layer by layer and bonding particles and layers to each other. We have considered the application areas of selective laser melting (SLM) based on powders obtained by different methods for the study. In addition, we have analyzed the traditional magnetic alloy casting technology, studied magnetic materials, and compared the powder magnet properties with standard data. We have found that the parameters of powders obtained by gas atomization are qualitatively superior to those of powders obtained using other methods, whereas the resulting magnets meet the requirements for magnets. Based on the 25Kh15KA alloy powder atomized by gas atomization, a SLM plant allows to manufacture permanent magnets with a material density of 7.59–7.55 g/cu.cm, which meets the requirements recommended by the State Standard GOST 24897-81, and to obtain the magnet properties that can be achieved using traditional metallurgical technologies.


2015 ◽  
Vol 651-653 ◽  
pp. 1519-1524 ◽  
Author(s):  
Laurent van Belle ◽  
Alban Agazzi

The Selective Laser Melting (SLM) process of metallic powder is an additive technology. It allows the production of complex-shaped parts which are difficult to obtain by conventional methods. The principle is similar to Selective Laser Sintering (SLS) process: it consists, from an initial CAD model, to create the desired part layer by layer. The laser scans a powder bed of 40 μm thick. The irradiated powder is instantly melted and becomes a solid material when the laser moves away. A new layer of powder is left and the laser starts a new cycle of scanning. The sudden and intense phase changing involves high thermal gradients which induce contraction and expansion cycles in the part. These cycles results in irreversible plastic strains. The presence of residual stresses in the manufactured part can damage the mechanical properties, such as the fatigue life. This study focuses on the thermal and mechanical modelling of the SLM process. One of the key points of the mechanical modelling is the determination of the heat source generated by the laser in order to predict residual stresses. This work is divided in three parts. In a first part, an experimental protocol is established in order to measure the temperature variation during the process. In the second part, a thermal model of the process is proposed. Finally, an inverse method to determine the power and the shape of the heat source is developed. Experimental and computational results are fitted. The influence of several geometries of the heat source is investigated.


Author(s):  
I. E. Mal’tzev ◽  
A. A. Basov ◽  
M. A. Borisov ◽  
A. V. Bystrov

The article discusses the course and results of experimental work on the initial study of the possibility of using one of the varieties of additive technologies – the method of layer-by-layer selective laser melting (SLM) in the manufacture of elements of heat exchangers and hydraulic circuits of spacecraft. Traditional manufacturing techniques for hydro-control elements and spacecraft heat exchangers are based on machining and high-temperature vacuum soldering, leading to a long cycle and high manufacturing costs. As an alternative, the method of layer-by-layer selective laser melting can be considered as a manufacturing method using a three-dimensional model of the product and not requiring additional equipment. This method is based on sequential layer-by-layer fusion of a metal powder with previous fused product layers under the action of a laser beam forming a local region of liquid melt. The article describes experimental work to assess the possibility of using the selective laser melting method. Assessed weld-ability of a sample made by selective laser fusion technology with tips made by traditional technology. Directions for testing the method of selective laser sintering on real structures of heat exchanging units of spacecraft have been determined. A technique is proposed and the results of a study of a sample synthesized by selective laser sintering are presented. Based on the results obtained, an analysis is made of the prospects for using this method in the production of elements of hydraulic circuits and heat exchange units of spacecraft.


2018 ◽  
Vol 8 (10) ◽  
pp. 1879 ◽  
Author(s):  
Luis Santos ◽  
Joel de Jesus ◽  
José Ferreira ◽  
José Costa ◽  
Carlos Capela

Selective Laser Melting (SLM) is currently one of the more advanced manufacturing and prototyping processes, allowing the 3D-printing of complex parts through the layer-by-layer deposition of powder materials melted by laser. This work concerns the study of the fracture toughness of maraging AISI 18Ni300 steel implants by SLM built over two different conventional steels, AISI H13 and AISI 420, ranging the scan rate between 200 mm/s and 400 mm/s. The SLM process creates an interface zone between the conventional steel and the laser melted implant in the final form of compact tension (CT) samples, where the hardness is higher than the 3D-printed material but lower than the conventional steel. Both fully 3D-printed series and 3D-printed implants series produced at 200 mm/s of scan rate showed higher fracture toughness than the other series built at 400 mm/s of scan rate due to a lower level of internal defects. An inexpressive variation of fracture toughness was observed between the implanted series with the same parameters. The crack growth path for all samples occurred in the limit of interface/3D-printed material zone and occurred between laser melted layers.


2021 ◽  
Vol 58 (10) ◽  
pp. 630-643
Author(s):  
F. Trauter ◽  
J. Schanz ◽  
H. Riegel ◽  
T. Bernthaler ◽  
D. Goll ◽  
...  

Abstract Fe-Nd-B powders were processed by additive manufacturing using laboratory scale selective laser melting to produce bulk nanocrystalline permanent magnets. The manufacturing process was carried out in a specially developed process chamber under Ar atmosphere. This resulted in novel types of microstructures with micrometer scale clusters of nanocrystalline hard magnetic grains. Owing to this microstructure, a maximum coercive field strength (coercivity) μ0Hc of 1.16 T, a remanence Jr of 0.58 T, and a maximum energy product (BH)max of 62.3 kJ/mm3could, for example, be obtained for the composition Nd16.5-Pr1.5-Zr2.6-Ti2.5-Co2.2-Fe65.9-B8.8.


Author(s):  
Mohammad Masoomi ◽  
Xiang Gao ◽  
Scott M. Thompson ◽  
Nima Shamsaei ◽  
Linkan Bian ◽  
...  

Selective Laser Melting (SLM), a laser powder-bed fusion (PBF-L) additive manufacturing method, utilizes a laser to selectively fuse adjacent metal powders. The powders are aligned in a bed that moves vertically to allow for layer-by-layer part construction-Process-related heat transfer and thermal gradients have a strong influence on the microstructural features, and subsequent mechanical properties, of the parts fabricated via SLM. In order to understand and control the heat transfer inherent to SLM, and to ensure high quality parts with targeted microstructures and mechanical properties, comprehensive knowledge of the related energy and mass transport during manufacturing is required. In this study, the transient temperature distribution within and around parts being fabricated via SLM is numerically simulated and the results are provided to aid in quantify the SLM heat transfer. In order to verify simulation output, and to estimate actual thermal gradients and heat transfer, experiments were separately conducted within a SLM machine using a substrate with embedded thermocouples. The experiments focused on characterizing heat fluxes during initial deposition on an initially-cold substrate and during the fabrication of a thin-walled structure built via stainless steel 17-4 powders. Results indicate that it is important to model heat transfer thorough powder bed as well as substrate.


2020 ◽  
Vol 62 (1-2) ◽  
pp. 76-80
Author(s):  
P. A. Kuznetsov ◽  
I. V. Shakirov ◽  
V. V. Bobyr’ ◽  
A. S. Zhukov ◽  
V. N. Klimov

2019 ◽  
Vol 31 (2) ◽  
pp. 022306 ◽  
Author(s):  
Wei Lin ◽  
Denise Albertazzi Gonçalves ◽  
Adriano de Souza Pinto Pereira ◽  
Milton Pereira ◽  
Walter Lindolfo Weingaertner

2014 ◽  
Vol 783-786 ◽  
pp. 898-903 ◽  
Author(s):  
Anne Mertens ◽  
Sylvie Reginster ◽  
Quentin Contrepois ◽  
Thierry Dormal ◽  
Olivier Lemaire ◽  
...  

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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