Additive Manufacturing of Co-Ni-Ga High-Temperature Shape Memory Alloy: Processability and Phase Transformation Behavior

Lauhoff, C.; Fischer, Andreas; Sobrero, C.; Liehr, A.; Krooß, P.; Brenne, F.; Richter, Julia; Kahlert, Moritz; Böhm, Stefan; Niendorf, Т.

doi:10.1007/s11661-019-05608-z

Cited by 26 publications

(11 citation statements)

References 49 publications

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“…Figure 1) and, concomitantly, stress concentrations at unfavorable GB arrangements are avoided. Finally, in contrast to recent findings for Co-Ni-Ga HT-SMA processed by SLM using lower temperatures [25], material without substantial crack formation has been obtained due to a reduction of internal stresses and a suppression of the thermally induced MT upon cooling.…”

Section: Resultscontrasting

confidence: 74%

“…In consequence, alloy-specific microstructural design seems to be highly promising to provide for enhanced functional material properties in anisotropic SMAs. In a very recent study, the present authors processed Co-Ni-Ga HT-SMA via powder-bed based selective laser melting (SLM) technique [25]. Using this technique, a columnar-grained microstructure evolved.…”

Section: Introductionmentioning

confidence: 99%

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Excellent superelasticity in a Co-Ni-Ga high-temperature shape memory alloy processed by directed energy deposition

Lauhoff

Sommer

Vollmer

et al. 2020

Materials Research Letters

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A Co-Ni-Ga high-temperature shape memory alloy has been additively manufactured by directed energy deposition. Due to the highly anisotropic microstructure, i.e. columnar grains featuring a strong near-001 texture in build direction, the as-built material is characterized by a very low degree of constraints and, thus, shows excellent superelasticity without conducting a post-process heat treatment. As characterized by in situ deformation testing and post-mortem microstructural analysis, additive manufacturing employing directed energy deposition seems to be highly promising for processing of shape memory alloys, which often suffer difficult workability. IMPACT STATEMENTThe present work establishes a new pathway towards realization of high performance shape memory alloys by additive manufacturing and, thus, will stimulate further research in this field directed towards application.

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Section: Resultscontrasting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Excellent superelasticity in a Co-Ni-Ga high-temperature shape memory alloy processed by directed energy deposition

Lauhoff

Sommer

Vollmer

et al. 2020

Materials Research Letters

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“…For studies on the influence of different microstructures, the Co–Ni–Ga FMSMA was additively manufactured by two different techniques, namely, L‐PBF and DED. For fabrication, spherical‐shaped Co–Ni–Ga powder [ 22 ] was obtained by gas atomization of the as‐cast material carried out by TLS Technik (Bitterfeld, Germany). Its chemical composition was double checked using energy‐dispersive X‐Ray spectroscopy (EDS), conforming the same composition as the as‐cast material (Co 49 Ni 21 Ga 30 ), within the accuracy of the EDS technique.…”

Section: Methodsmentioning

confidence: 99%

“…[19][20][21] For Co-Ni-Ga alloys, a highly anisotropic microstructure, that is, columnar grained and in some cases even strongly textured, could be realized using additive manufacturing, namely, laser powder bed fusion (L-PBF) and direct energy deposition (DED). [22][23][24] During the L-PBF process, prealloyed powder is molten layer by layer utilizing a laser system operating under inert gas atmosphere to prevent oxidation. The microstructure can be directly tailored by choice of suitable processing parameters like laser power, hatch spacing, layer thickness, or scanning speed and strategy.…”

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confidence: 99%

On the Impact of Additive Manufacturing Processes on the Microstructure and Magnetic Properties of Co–Ni–Ga Shape Memory Heusler Alloys

et al. 2022

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Ferromagnetic shape memory alloys (FMSMAs) show a large magnetic fieldinduced strain up to 10%, [1,2] which makes this materials interesting for magnetic actuators. [3] A promising material class for FMSMAs are Heusler alloys, such as Ni-Mn-X (X: Ga, In, Sn, Al), [2,[4][5][6][7][8] Ni-Fe-Ga, [9] or Co-Ni-X (X: Al, Ga), [10][11][12] exhibiting a large shape memory effect owing to a reversible martensitic transformation. The investigated Co-Ni-Ga Heusler alloy undergoes a first-order magnetostructural transformation (FOMST) from hightemperature B2-ordered austenite to lowtemperature tetragonal L1 0 martensite. [13] A fully reversible superelastic response as well as excellent cyclic stability up to temperatures of 373 K has been reported for single crystals. [12] However, polycrystalline Co-Ni-Ga as well as other polycrystalline Heusler alloys suffer from intergranular cracking and premature failure after several transformation cycles due to the anisotropic volume change of randomly orientated grains. [14,15]

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“…Reasons for intensive research on CoNiGa alloys are high Curie temperature, exceptional hightemperature pseudoelastic properties and the ability to modify the properties of the material with heat treatment (Kuksgauzen et al, 2015;Gerstein et al, 2018;Lauhoff et al, 2018Lauhoff et al, , 2019Kuksgauzen et al, 2019). The latest use of Co-Ni-Ga MSMAs includes selective laser melting printing (Lauhoff et al, 2020) and the use of the material in the form of the nanoparticles (Wang et al, 2015(Wang et al, , 2017.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature martensite relaxation in Co–Ni–Ga shape memory alloy monocrystal revealed using in situ cooling, transmission electron microscopy and low rate calorimetry

Żak¹,

Dańczak²,

Dudziński³

2020

Acta Crystallogr Sect B

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This work presents the results of research on a Co49Ni21Ga30 magnetic shape memory single crystal. Based on a literature review, it was identified that analyses of phase transformations have been limited to specific heating and cooling rates, which could lead to an incomplete description of the resulting phenomena. Differential scanning calorimetry (DSC) performed with different heating/cooling rates enabled the precise determination of enthalpy values, which deviate from literature values. Weak and previously unnoticed thermal phenomena at temperatures below 190 K were also observed. Their presence was confirmed by low-temperature in situ transmission electron microscopy (TEM). Through DSC measurements and TEM observations, a model of the discovered phenomenon was proposed, which may have an impact on a better understanding of the physics of magnetic shape memory materials.

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Additive Manufacturing of Co-Ni-Ga High-Temperature Shape Memory Alloy: Processability and Phase Transformation Behavior

Cited by 26 publications

References 49 publications

Excellent superelasticity in a Co-Ni-Ga high-temperature shape memory alloy processed by directed energy deposition

Excellent superelasticity in a Co-Ni-Ga high-temperature shape memory alloy processed by directed energy deposition

On the Impact of Additive Manufacturing Processes on the Microstructure and Magnetic Properties of Co–Ni–Ga Shape Memory Heusler Alloys

Low-temperature martensite relaxation in Co–Ni–Ga shape memory alloy monocrystal revealed using in situ cooling, transmission electron microscopy and low rate calorimetry

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