Selective laser melting of pure iron: Multiscale characterization of hierarchical microstructure

Lejček, Pavel; Roudnická, Michaela; Čapek, Jaroslav; Dvorský, Drahomír; Drahokoupil, Jan; Šimek, Daniel; Čı́žek, Jakub; Svora, Petr; Molnárová, Orsolya; Vojtěch, Dalibor

doi:10.1016/j.matchar.2019.05.012

Cited by 36 publications

(13 citation statements)

References 33 publications

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“…An irregular grain morphology similar to that of the EBM‐processed cp‐Fe presented herein was already reported for Fe after SLM. In studies published by Lejček et al [ 22 ] and Song et al, [ 23 ] this kind of final microstructural appearance was rationalized based on multiple α ↔ γ phase transformations, which in turn led to a fragmentation of priorly columnar solidified grains. Furthermore, the high dislocation density found in these studies was attributed to thermal contraction resulting from high cooling rates, leading in turn to work hardening of the material.…”

Section: Resultsmentioning

confidence: 99%

“…According to the aforementioned studies, [ 2,22,23 ] a tendency to grain fragmentation can be seen in case of AM processing of Fe‐based alloys. In these studies it is considered that grain refinement stems from the intrinsic heat treatment being characteristic of any AM process.…”

Section: Resultsmentioning

confidence: 99%

“…Apart from this, a grain refinement can also proceed as a consequence of repeated allotropic phase transformations. As stated in Lejček et al, [ 22 ] previously columnar grains can disaggregate in consequence of repeated phase transformations: First, an epitaxial solidification in the melt pool (at the bottom) enforces a columnar grain growth due to the selection of preferred orientations aligned to the temperature gradient. Thereby, as a result of extremely high cooling rates prevailing directly upon solidification, α phase grains are formed directly.…”

Section: Resultsmentioning

confidence: 99%

“…Lejček et al [ 22 ] processed cp‐Fe via selective laser melting (SLM) as a model material and reported on hierarchical structures consisting of subgrains and cells resulting from multiple α ↔ γ phase transformations during AM processing. Song et al [ 23 ] correlated the applied SLM process parameters to the microstructure as well as dislocation density of cp‐Fe and proposed a method to tailor the ultimate tensile strength.…”

Section: Introductionmentioning

confidence: 99%

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On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting

et al. 2021

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Additive manufacturing (AM) processes such as electron beam melting (EBM) are characterized by unprecedented design freedom. Topology optimization and design of the microstructure of metallic materials are enabled by rapid progress in this field. The latter is of highest importance as many applications demand appropriate mechanical as well as functional material properties. For instance, biodegradable implants have to meet mechanical properties of human bone and at the same time guarantee adequate cytocompatibility and degradation rate. In this field, pure iron has come into focus in recent studies due to its low toxicity. Hierarchical microstructures resulting from the EBM solidification processes and intrinsic heat treatment, respectively, allow for an adjustment of the degradation behavior and may promote enhanced fatigue strength. Herein, commercially pure iron (cp‐Fe) is processed by EBM. Microstructural analysis as well as an evaluation of the cyclic mechanical material properties are conducted. The results are compared to a hot‐rolled (HR) reference material. A contradiction observed as the EBM‐processed cp‐Fe (EBM Fe) shows lower ultimate tensile strength under monotonic loading but improved fatigue properties compared to the HR Fe. It is revealed that such a unique behavior originates from prevailing microstructural features in the EBM as‐built condition.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting

et al. 2021

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“…It is conducted in the layer-by-layer manner so that the laser beam melts only a small volume of powder each time. As a result, rapid cooling the melt at rates up to 103-106 K/s occurs during SLM [32,[51][52][53]. The rapidly solidified microstructure is therefore extremely fine (Figures 5, 7 In cross-section, the yttrium oxide inclusions have a typical elongated "river-like" shape, suggesting that their origin is in the oxide shells on the particles of the input powder.…”

Section: Microstructure and Chemical Compositionmentioning

confidence: 99%

Biodegradable WE43 Magnesium Alloy Produced by Selective Laser Melting: Mechanical Properties, Corrosion Behavior, and In-Vitro Cytotoxicity

Lovašiová

Lovaši

Kubásek

et al. 2022

Metals

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In this work, selective laser melting (SLM) technology was used to prepare Mg-4Y-3Nd-Zr (WE43) alloy. This alloy and production method are promising for the design of biodegradable implants. The aim of this study was to investigate the chemical composition, microstructure, mechanical properties, corrosion behavior in simulated body fluid (SBF), and cytotoxicity of the alloy produced by SLM method and to compare it with conventionally gravity cast reference alloy. Analysis of the surface of the revealed an oxygen content of 7 wt.%. Undesirable unmelted and only partially adhered spherical particles of the starting powder were also found. The microstructure of the material was very fine and consisted of α-Mg dendritic matrix, β-Mg41(Nd, Y)5 intermetallic phase, Y2O3 inclusions, and 0.6 vol.% of residual porosity. The Vickers hardness, compressive yield strength, compressive strength, and maximum compressive strain were 88 HV0.1, 201 MPa, 394 MPa, and 14%, respectively, which are close to the reference values in as-cast. The in vitro corrosion rates determined by immersion and potentiodynamic tests were 2.6 mm/year and 1.3 mm/year, respectively. Cytotoxicity tests indicated good biocompatibility of the 3D-printed alloy.

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Modification of Iron with Degradable Silver Phases Processed via Laser Beam Melting for Implants with Adapted Degradation Rate

et al. 2022

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Selective laser melting of pure iron: Multiscale characterization of hierarchical microstructure

Cited by 36 publications

References 33 publications

On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting

On the Microstructural and Cyclic Mechanical Properties of Pure Iron Processed by Electron Beam Melting

Biodegradable WE43 Magnesium Alloy Produced by Selective Laser Melting: Mechanical Properties, Corrosion Behavior, and In-Vitro Cytotoxicity

Modification of Iron with Degradable Silver Phases Processed via Laser Beam Melting for Implants with Adapted Degradation Rate

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