Mater.Sci.Res.Int. 1, 23-30, 1995


OVERALL THERMOMECHANICAL BEHAVIOR OF
SHAPE MEMORY ALLOYS
A Micromechanical Approach Based on
Mean Field Theory

K. Tanaka¹, D. Hasegawa¹, H.J. Böhm² and F.D. Fischer³

¹Department of Aerospace Engineering,
Tokyo Metropolitan Institute of Technology, Hino, Japan
²Institute of Lightweight Structures and Aerospace Engineering,
TU Wien, Vienna, Austria
³Christian Doppler Laboratory for Micromechanics of Materials
University for Mining and Metallurgy, Leoben, Austria


Abstract - Overall thermomechanical behavior of polycrystalline shape memory allyos is described from the micromechanical point of view by modeling the alloys as a matrix-inclusion material system. The martensite inclusions are assumed to be born in the austenite matrix at the moment when a transformation condition is satisfied there during thermomechanical loading. The macroscopic constitutive equation is derived in rate form by means of Eshelby's inhomogeneous theory. The Mori-Tanaka theory is employed to take into account the interaction of the martensite inclusions. The formula of the overall thermomechanical material parameters, which exhibits the effect of transformation, is derived explicitly.


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