Relationship between laser energy input, microstructures and magnetic properties of selective laser melted Fe-6.9%wt Si soft magnets

Garibaldi, Michele; Ashcroft, Ian; Hillier, Nicholas; Harmon, Stuart; Hague, Richard

doi:10.1016/j.matchar.2018.01.016

Cited by 104 publications

(42 citation statements)

References 12 publications

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“…All of the above considerations lead to concluding that this kind of alloy requires being printed at a low enough laser energy input to avoid transition or keyhole regimes, preventing both porosities and cracks. Absorptivity, printing modes' limits (conduction and keyhole), and porosity, derived through numerical modeling of the processes described in [10] and [13], referring to steels with 6.7% and 6.9% Si. Absorptivity, printing modes' limits (conduction and keyhole), and porosity, derived through numerical modeling of the processes described in [10,13], referring to steels with 6.7% and 6.9% Si.…”

Section: Methodsmentioning

confidence: 99%

Properties of Additively Manufactured Electric Steel Powder Cores with Increased Si Content

et al. 2021

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In this paper, the best laser powder bed fusion (L-PBF) printing conditions for FeSi steels with two different Si content (3.0% and 6.5%) are defined. Results show very strict processing window parameters, following a lack of fusion porosity at low specific energy values and keyhole porosity in correspondence with high specific energy values. The obtained microstructure consists of grains with epitaxial growth starting from the grains already solidified in the underling layer. This allows the continuous growth of the columnar grains, directed parallel to the built direction of the component. The magnetic behaviour of FeSi6.5 samples, although the performances found do not still fully reach those of the best commercial electrical steels (used to manufacture magnetic cores of electrical machines and other similar magnetic components), appears to be quite promising. An improvement of the printing process to obtain thin sheets with increased Si content, less than 0.5 mm thick, with accurate geometry and robust structures, can result to an interesting technology for specific application where complex geometries and sophisticated shapes are required, avoiding mechanical machining processes for electrical steel with high silicon content.

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Section: Methodsmentioning

confidence: 99%

Properties of Additively Manufactured Electric Steel Powder Cores with Increased Si Content

et al. 2021

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“…The as-built microstructure consisted of fine equiaxed grains, not very typical for materials processed using LENS and other welding based processes for which columnar grains and epitaxial growth is more common. Materials investigated in association with L-PBF include Ni-Fe14-Cu5-Mo4 (Bauer et al, 2016), Fe-Ni (Zhang et al, 2013a(Zhang et al, , 2013b and Fe-6.9 wt% Si steel (Garibaldi et al, 2016(Garibaldi et al, , 2018a(Garibaldi et al, , 2018b, where the latter has been studied most extensively. Bauer et al (2016) used a re-melt scanning strategy and observed that it resulted in a more homogeneous microstructure compared to single scan strategy and increased porosity as well as grain size.…”

Section: Introductionmentioning

confidence: 99%

Properties of soft magnetic Fe-Co-V alloy produced by laser powder bed fusion

Riipinen

Metsä-Kortelainen

Lindroos

et al. 2019

RPJ

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Purpose The purpose of this paper is to report on the developments in manufacturing soft magnetic materials using laser powder bed fusion (L-PBF). Design/methodology/approach Ternary soft magnetic Fe-49Co-2V powder was produced by gas atomization and used in an L-PBF machine to produce samples for material characterization. The L-PBF process parameters were optimized for the material, using a design of experiments approach. The printed samples were exposed to different heat treatment cycles to improve the magnetic properties. The magnetic properties were measured with quasi-static direct current and alternating current measurements at different frequencies and magnetic flux densities. The mechanical properties were characterized with tensile tests. Electrical resistivity of the material was measured. Findings The optimized L-PBF process parameters resulted in very low porosity. The magnetic properties improved greatly after the heat treatments because of changes in microstructure. Based on the quasi-static DC measurement results, one of the heat treatment cycles led to magnetic saturation, permeability and coercivity values comparable to a commercial Fe-Co-V alloy. The other heat treatments resulted in abnormal grain growth and poor magnetic performance. The AC measurement results showed that the magnetic losses were relatively high in the samples owing to formation of eddy currents. Research limitations/implications The influence of L-PBF process parameters on the microstructure was not investigated; hence, understanding the relationship between process parameters, heat treatments and magnetic properties would require more research. Originality/value The relationship between microstructure, chemical composition, heat treatments, resistivity and magnetic/mechanical properties of L-PBF processed Fe-Co-V alloy has not been reported previously.

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“…Specific work in intermetallics has been focused on materials such as titanium aluminides for high temperature strength, oxidation resistance, and creep resistance in the aerospace industry [1][2][3][4], or nickel titanium intermetallics for shape memory, damping, and biocompatibility for implants in the medical industry [5][6][7][8][9]. Only a few publications have investigated the potential for the selective laser melting (SLM) of magnetic intermetallics [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Grain Size Effects in Selective Laser Melted Fe-Co-2V

Everhart

Newkirk

2019

Applied Sciences

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The material science of additive manufacturing (AM) has become a significant topic due to the unique way in which the material and geometry are created simultaneously. Major areas of research within inorganic materials include traditional structural materials, shape memory alloys, amorphous materials, and some new work in intermetallics. The unique thermal profiles created during selective laser melting (SLM) may provide new opportunities for processing intermetallics to improve mechanical and magnetic performance. A parameter set for the production of Fe-Co-2V material with additive manufacturing is developed and efforts are made to compare the traditional wrought alloy to the AM version of the same chemistry. Evaluation includes magnetic properties, composition, and phase as a function of thermal history, as well as mechanical performance. Results show significant similarities in microstructure between AM and wrought materials, as well as mechanical and magnetic performance. Property trends are evaluated as a function of grain size and show effects similar to the Hall–Petch strengthening observed in wrought material, though with some underprediction of the strength. Magnetic properties qualitatively follow the expected trends but demonstrate some deviation from wrought material, which is still unexplained.

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Relationship between laser energy input, microstructures and magnetic properties of selective laser melted Fe-6.9%wt Si soft magnets

Cited by 104 publications

References 12 publications

Properties of Additively Manufactured Electric Steel Powder Cores with Increased Si Content

Properties of Additively Manufactured Electric Steel Powder Cores with Increased Si Content

Properties of soft magnetic Fe-Co-V alloy produced by laser powder bed fusion

Grain Size Effects in Selective Laser Melted Fe-Co-2V

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