Shape memory alloys, Part I: General properties and modeling of single crystals

International audienceThis two-part paper reviews the latest developments in the modeling of shape memory alloys (SMAs) constitutive behavior. The basic properties of SMAs are presented in Part I, including the shape memory effect, pseudoelasticity, as well as other properties such as the acquired and two-way shape memory effect, damping capacity and fatigue life. Part I focuses on the modeling at the single crystal level, dealing with the kinematics of the phase transformation and addressing different approaches for the development of the free energy and dissipation in order to derive constitutive equations. Some of the commonly used SMAs are reviewed by chemical composition and thermomechanical properties. The effects that different processing techniques have on their properties are also discussed. The kinematics associated with the martensitic phase transformation in a single crystal is described for a cubic to tetragonal and cubic to monoclinic transformation, and the lattice invariant strain by plastic slip is discussed. The transformation strain in a representative volume element (RVE) and its evolution are then defined. The free energy and dissipative potentials are derived together with the interaction energy for single variant and multivariant formulations in single crystals. A discussion on scale transitions to polycrystalline SMAs is finally presented. Part II deals with the polycrystalline modeling, considering both micromechanical approaches and phenomenological ones. It also includes considerations about the numerical implementation of SMA constitutive models and their integration into finite element codes