Multiscale bifurcation and stability of multilattices
by
Ryan S. Elliott
in
Journal of Computer-Aided Materials Design, 14(Supplement 1):143-157, 2007.
Category: Journal Article
Click here to request an electronic copy of this paper.
Abstract:
A lattice-level model is developed for active materials, such as shape memory alloys, that undergo martensitic phase transformations. The model is investigated using equilibrium path following and bifurcation techniques. It is shown that a multiscale stability criterion is essential for correctly interpreting the stability of crystal equilibrium configurations under both thermal- and stress-loading conditions. A two-stage temperature-induced phase transformation is predicted from a cubic $B2$ phase to an orthorhombic Cmmm phase to a final orthorhombic $B19$ phase. Under stress-loading conditions, martensitic transformations from the $B2$ austenite phase to a number of possible martensite phases are identified. These include reconstructive transformations to $B11$, $B33$, and $C2/m$ structures and proper transformation to a $C2/m$ monoclinic phase which displays characteristic tension-compression asymmetry. The prediction of both temperature-induced and stress-induced proper martensitic transformations indicates the likelihood that the current model will exhibit shape memory behavior.
This entry has been accessed 707 times.