In situ synchrotron analysis of lattice rotations in individual grains during stress-induced martensitic transformations in a polycrystalline CuAlBe shape memory alloy

Sophie Berveiller (1) , Benoît Malard (1) , Jonathan Wright (2) , Etienne Patoor (1) , Guillaume Geandier (2)

1 LEM3 - Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux
2 ESRF - European Synchrotron Radiation Facility

Two synchrotron diffraction techniques, three-dimensional X-ray diffraction and Laue microdiffraction, are applied to studying the deformation behaviour of individual grains embedded in a Cu74Al23Be3 superelastic shape memory alloy. The average lattice rotation and the intragranular heterogeneity of orientations are measured during in situ tensile tests at room temperature for four grains of mean size 1 mm. During mechanical loading, all four grains rotate and the mean rotation angle increases with austenite deformation. As the martensitic transformation occurs, the rotation becomes more pronounced, and the grain orientation splits into several sub-domains: the austenite orientation varies on both sides of the martensite variant. The mean disorientation is 1 . Upon unloading, the sub-domains collapse and reverse rotation is observed.

Mots clés: Shape memory alloy; 3D-XRD synchrotron; Crystal lattice rotation; CuAlBe shape memory alloy; Superelasticity

Domaines: Matériaux; Mécanique des matériaux [physics.class-ph]

Sophie Berveiller, Benoît Malard, Jonathan Wright, Etienne Patoor, Guillaume Geandier. In situ synchrotron analysis of lattice rotations in individual grains during stress-induced martensitic transformations in a polycrystalline CuAlBe shape memory alloy. Acta materalia, 2011, 59 (9), pp.3636-3645. ⟨10.1016/j.actamat.2011.02.037⟩. ⟨hal-01195642⟩