Control of microstructure and shape memory properties of a Fe-Mn-Si-based shape memory alloy during laser powder bed fusion

Ferretto, Irene; Borzì, A.; Kim, D.; Ventura, Nicoló Maria della; Hosseini, E.; Lee, W.J.; Leinenbach, Christian

doi:10.1016/j.addlet.2022.100091

Cited by 23 publications

(15 citation statements)

References 55 publications

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“…Evaporation of alloying elements, especially of manganese, due to welding processes of high manganese steels was reported in numerous studies. In particular for additive manufacturing of Fe-34Mn-15Al-7.5Ni-at.% [48] and Fe-17Mn-5Si-10Cr-4Ni-1(V,C)-wt.% [49] by laser powder bed fusion high losses of manganese are reported. Moreover, Gu ¨nther et al [50] show significant evaporation of manganese with increasing energy input during electron beam melting of Cr-Mn-Ni TRIP steel.…”

Section: Resultsmentioning

confidence: 99%

Electron Beam Welding of Hot-Rolled Fe–Mn–Al–Ni Shape Memory Alloy Sheets

Bauer

Wiegand

Wicke

et al. 2023

Shap. Mem. Superelasticity

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The present study focuses on the weldability of hot-rolled Fe–Mn–Al–Ni shape memory alloy sheets by vacuum electron beam welding. Tailored process-specific welding parameters, such as preheating with electron beam or beam oscillation during welding, allowed defect-free joining with very thin weld seams and heat-affected zones. By applying a post-weld cyclic heat treatment, abnormal grain growth can be promoted across the weld seams. However, regardless of the selected welding parameters, some specimens are characterized by the formation of smaller grains within the former fusion zone. In situ incremental strain tests reveal that the former fusion zone has only a minor influence on the functional properties and is not responsible for structural failure. Thus, electron beam welding is a promising welding technology for joining Fe–Mn–Al–Ni shape memory alloys.

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Section: Resultsmentioning

confidence: 99%

Electron Beam Welding of Hot-Rolled Fe–Mn–Al–Ni Shape Memory Alloy Sheets

Bauer

Wiegand

Wicke

et al. 2023

Shap. Mem. Superelasticity

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“…The beam is polarized by a multichannel polarizing-bender unit, which at BOA is permanently installed upstream of the collimation The material studied in this work is an Fe-based SMA with the nominal composition Fe-17Mn-5Si-10Cr-4Ni-1(V,C) (wt. %) from previous studies reported in Refs [3,22]. The powder was produced by gas atomization in Ar atmosphere (Boehler Edelstahl, Kapfenberg, Austria) and is characterized by spherical particles with a radius of 33 µm and a size distribution between 22 and 48 µm.…”

Section: Methods and Experimentsmentioning

confidence: 99%

“…By varying the LPBF process parameters, components with tailored phase volume fractions, grain size and texture can be fabricated, as the thermal history in the deposited material can be site-specifically controlled and modified [2]. In a recent study [3], it has been demonstrated that the microstructure of a Fe-Mn-Si-based SMA could be varied in a rather wide range by simply changing the laser scan velocity during LPBF. Specifically, the volume phase fraction of the bcc-δ ferrite and fcc-γ austenite phases could be tailored in the fabricated samples, showing an increase in material strength but a decrease in the shape memory properties with a higher amount of bcc-δ.…”

Section: Introductionmentioning

confidence: 99%

Time-of-flight polarization contrast neutron imaging for enhanced characterization of ferritic phase fractions in Fe-Mn-Si shape memory alloys

Busi,

Ferretto,

Malamud

et al. 2023

J. Phys.: Conf. Ser.

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The determination of the amount and distribution of different phase fractions in additively manufactured shape memory alloys processed with laser powder bed fusion is crucial for understanding the correlation between processing parameters, microstructure, and mechanical properties. Neutron imaging techniques, such as Bragg edge imaging and polarization contrast neutron imaging (PNI), have been introduced to complement and overcome the limitations of traditional characterization methods, which are often destructive and limited to surface analyses and small-sized specimens. Bragg edge imaging can distinguish and quantify crystallographic phase fractions with spatial resolutions of a few tens of micrometers, while PNI is highly sensitive to crystallographic phases and is particularly suited for sub-percent phase fractions and in-situ, time-resolved, and tomographic analyses. In this work, we present a time-of-flight PNI method that enables simultaneous measurements of phase fractions.

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“…In contrast to the copious literature on conventionally processed Fe-based SMAs, research on the additive manufacturing of this alloy system is in its infancy [20][21][22][23][24][25][26][27] . To the best of the authors' knowledge, alloy compositions of Fe-36Mn-7Al-9Ni (wt.%), Fe-17Mn-10Cr-5Si-4Ni (wt.%), and Fe-34Mn-8Al-7Ni (at.%) have been LPBF fabricated to date.…”

Section: Introductionmentioning

confidence: 99%

“…The authors suggested that the nucleation of the austenite grains from the δ-ferrite was possible at high laser power because of the low cooling rate in this setting. Lastly, Patriarca et al fabricated a bulk and micro-lattice structured Fe-34Mn-8Al-7Ni alloys and heat treated the alloys to achieve a microstructure desirable for the pseudoelastic property [27] .…”

Section: Introductionmentioning

confidence: 99%

Microstructure evolution in laser powder bed fusion-built Fe-Mn-Si shape memory alloy

2023

Microstructures

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The need for specialty powder composition limits the processing of a wide range of alloy products via the laser powder bed fusion (LPBF) technique. This work extends the adaptability of the LPBF technique by fabricating the first-ever Fe-30Mn-6Si (wt.%) product for potential use as a biodegradable shape memory alloy (SMA). Different LPBF processing parameters were assessed by varying the laser power, scan speed, and the laser re-scan strategy to achieve a fully dense part. The microstructure was found to respond to the processing conditions. For example, the microstructure of the parts produced by the high linear energy density (LED) had a columnar and strong crystallographic texture, while in the low LED, the parts were almost equiaxed and had a weak texture. To explain the evolved microstructure, the thermal history of the LPBF products was computed using the finite element analysis (FEA) of the melt pool gathered from a single-track laser scan experiment. The FEA results showed a varying temperature gradient, cooling and solidification rates, and temperature profile as a function of LED. Then, the relationship of hardness between grain size, phases present, and crystallographic misorientation of the LPBFbuilt alloy was analysed with reference to a control alloy of similar composition but prepared by arc melting. This study validates the LPBF processability of Fe-Mn-Si SMA and provides a new insight into the influence of processing parameters on the formed microstructure and hardness.

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Control of microstructure and shape memory properties of a Fe-Mn-Si-based shape memory alloy during laser powder bed fusion

Cited by 23 publications

References 55 publications

Electron Beam Welding of Hot-Rolled Fe–Mn–Al–Ni Shape Memory Alloy Sheets

Electron Beam Welding of Hot-Rolled Fe–Mn–Al–Ni Shape Memory Alloy Sheets

Time-of-flight polarization contrast neutron imaging for enhanced characterization of ferritic phase fractions in Fe-Mn-Si shape memory alloys

Microstructure evolution in laser powder bed fusion-built Fe-Mn-Si shape memory alloy

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