Characterization of Gas Atomized Ni-Mn-Ga Powders

Nilsén, Frans; Aaltio, Ilkka; Ge, Yanling; Lindroos, Tomi; Hannula, Simo‐Pekka

doi:10.1016/j.matpr.2015.07.422

Cited by 14 publications

(10 citation statements)

References 14 publications

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“…9b). A similar effect has been previously observed when magnetic properties of the as-atomized Ni-Mn-Ga powder are compared to heat-treated powder [19]. If the magnetization of the heat-treated powder and sintered samples are compared, the sintered samples have higher magnetization likely due to being solid and as they have larger grain size than the powder particles.…”

Section: Resultssupporting

confidence: 71%

“…20°C). The exact vacuum in the evacuated ampoules was not measured, however, the vacuum was pumped for over 30 min before sealing the ampoule and the expected level was of vacuum was better than 1.33 × 10-5 Pa, which we have measured previously when making similar heat-treatments in evacuated ampoules [16,19]. The crystal structures were studied using the PANalytical X'Pert Pro XRD and the magnetization of all samples was measured using a laboratory-built VSM applying a NIST nickel disk as a reference sample.…”

Section: Design Of Experiments For the Pbfmentioning

confidence: 99%

“…The atomization was carried out at VTT, Finland. The atomizing gas was argon and the atomization temperature was 1310°C and the pressure was 50 bar, the particle size of the powder was measured using Malvern Mastersizer 3000 and the D50 of the powder was 47.7 μm, the D10 was 17.5 μm and the D90 was 105 μm and the distribution followed the normal distribution as in previous experiments [19] and the measured density of the powder was 7.91 g/cm 3 , which is higher than the calculated theoretical density of 7.88 g/cm 3 indicating that there were no micropores [39]. To achieve an even flow of powder during the powder spreading in the PBF, the atomized powder was mechanically sieved [20] to obtain a size fraction from 25 μm to 45 μm.…”

Section: Powder Preparationmentioning

confidence: 99%

“…However, these techniques can produce structures of only limited sizes or foams with random distribution of pores. In the present study, we use powder bed fusion to manufacture samples from gas atomized Ni-Mn-Ga powder [19] having a nonmodulated crystal structure and good flowability [20].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of process parameters on non-modulated Ni-Mn-Ga alloy manufactured using powder bed fusion

Nilsén

Ituarte

Salmi

et al. 2019

Additive Manufacturing

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Increasingly, metal parts made by additive manufacturing are produced using powder bed fusion (PBF). In this paper we report upon the combined effects of PBF parameters, including power and scan speed, in layer-by-layer manufacturing of gas atomized non-modulated (NM) Ni-Mn-Ga alloy. The effects of process parameters upon PBF is studied by applying nine different parameter sets in the as-printed state and after homogenization and ordering. The chemical composition of the samples is analyzed using EDX attached to an SEM, and the crystal structures are determined by X-ray diffraction. The phase transformation temperatures are measured using a low-field ac susceptibility measurement system and the magnetic properties are measured with a vibrating sample magnetometer (VSM). Before the heat-treatment, all as-printed samples showed paramagnetic behavior with low magnetization and no phase transformations could be observed in the susceptibility measurements. After annealing, the samples recovered the ferromagnetic behavior with comparable magnetization to annealed gas atomized powder. The as-printed samples were composed of a mixture of different crystal structures. However, after annealing the original NM structure with a = b = 5.47 Å and c = 6.66 Å with a c/a-ratio of 1.22 was recovered and crystallographic twins could be observed in an SEM.

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Section: Resultssupporting

confidence: 71%

Section: Design Of Experiments For the Pbfmentioning

confidence: 99%

Section: Powder Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of process parameters on non-modulated Ni-Mn-Ga alloy manufactured using powder bed fusion

Nilsén

Ituarte

Salmi

et al. 2019

Additive Manufacturing

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“…Previous research has shown that Ni-Mn-Ga composites containing round particles have higher damping capabilities, as the round particles do not have a shape effect in the magnetic anisotropy [9]. The properties of gas atomized Ni-Mn-Ga powders have been studied previously [19] and the powder has been used to manufacture hybrid Ni-Mn-Ga composites [20].…”

Section: Introductionmentioning

confidence: 99%

Comparison of magnetic field controlled damping properties of single crystal Ni-Mn-Ga and Ni-Mn-Ga polymer hybrid composite structures

Nilsén

Aaltio

Hannula

2018

Composites Science and Technology

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Magnetically controlled hybrid Ni-Mn-Ga composites are potential candidates for actuation and damping applications. The combination of ductile polymer and gas atomized large grained Ni-Mn-Ga powder has many advantages compared to bulk single crystals. These advantages include ease of manufacturing and freedom of shape, while still being magnetically controllable. In this report, Ni-Mn-Ga-epoxy hybrid composite structures are manufactured at three different filling ratios 25, 30 and 35 vol-% and damping properties of the composites are compared to those of 5M Ni-Mn-Ga single crystal. The damping properties are characterized using a laboratory made high-frequency dynamic mechanical testing instrument and a dynamic mechanic analyzer (DMA) in single cantilever mode. The mechanical cycling experiments revealed that the damping ability of the Ni-Mn-Ga composites depends on the filling ratio. The magnetic field induced stiffening observed in the mechanical cycling experiments of the single crystal sample at 100 Hz correlated roughly with that of the composite sample having filling ratio of 35 vol-%.

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Motion and Solidification Behavior Analysis of Fe-Based Alloy Droplets During Gas Atomization

Zhou

et al. 2020

Metall Mater Trans B

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Characterization of Gas Atomized Ni-Mn-Ga Powders

Cited by 14 publications

References 14 publications

Effect of process parameters on non-modulated Ni-Mn-Ga alloy manufactured using powder bed fusion

Effect of process parameters on non-modulated Ni-Mn-Ga alloy manufactured using powder bed fusion

Comparison of magnetic field controlled damping properties of single crystal Ni-Mn-Ga and Ni-Mn-Ga polymer hybrid composite structures

Motion and Solidification Behavior Analysis of Fe-Based Alloy Droplets During Gas Atomization

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