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Thermophysical properties of magnetic Thermophysical properties of magnetic Shape Memory Alloys
J. Brilloa, I. Egrya, Yu. Plevachukb
aDeutsches Zentrum für Luft- und Raumfahrt (DLR), Köl n, Germany
bIvan Franko National University, Lviv, Ukraine
EFAM project:
Objective:Development of energy efficient shape memory actuators for automotive applications
Material („desgined from the melt“):Ni-Mn-Ga-X (magnetic shape memory alloy)
Partners:
(coordination)
ETO MAGNETIC GmbH
Stockach Access e.V.an der
RWTH Aachen0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0,0 0,2 0,4 0,6 0,8 1,0 1,2
De
hn
un
g (
mm
)
Magnetfeld (T)
Dehnung-Feld-Kennlinie mit 1,5 MPa Vorspannung
Probengröße: 3x5x20 mm
Fraunhofer IWUInstitut für Werkzeugmaschinen
und Umformtechnik
Chemnitz & Dresden
ALD VacuumTechnologies
Hanau
DLRInstitut für
Materialphysikim Weltraum
Köln
DLR contribution:
Determination of thermophysical property dataneeded for simulation of foundring process, and formation of single crystalls, the configuration of the production furnace, and material characterization:
• density (liquid)• transition temperatures / heat of fusion (solid/liquid)• specific heat (solid/liquid)• specific heat (solid/liquid)• thermal diffusivity and conductivity (solid/liquid)• viscosity (liquid)• rate of evaporation (liquid)
Alloys (Ni-Mn-Ga-X) denoted A001, A002, B002exact composition is confidential
Density
Electromagnetic Levitation
DSC results
TS = 1114 °C TL = 1137 °C Hf = 257 J / gA002
Specific heat
Λ– transition at 755 °C, cP dependend on heating rate
Thermal diffusivity
2 < αααα[mm2/s] < 6.0 & dip at 700 °C
ραλ pc=
Thermal conductivity
For the liquid:λ = ?
ραλ pc=
Steady state concentric cylinder method
Thermal conductivity
Summary / Outlook
A comprehensive set of thermophysical property data could be established, although this a difficult system(high vapour pressure, very reactive)
Future:
Identification of key-properties which are to be investigated systematically over a broad concentration range
Future:
