Characterization of an Fe-Mn-Si-Cr-Ni shape memory alloy by X-ray diffraction and Electron Backscatter Diffraction

V. FUSTER; M. ÁVALOS; A.V. DRUKER; R. BOLMARO

Concepción

Congreso; Congreso Binacional de Metalurgia y Materiales CONAMET/SAM 2015; 2015

Departamento de Ingeniería de Materiales (DIMAT)-Universidad de Concepción

The shape memoryeffect (SME) of Fe-based alloys is due to a reversible martensitictransformation g (FCC) to e(HCP), induced by stress and reverted by heat-treatment above Af. In this condition, the martensitic variants most favorable oriented with respect to the applied stress axis develop. Numerous studies suggest that theimprovement of the SME can be achieved by controlling the material microstructural properties, namely by grain size refinement, austenitic matrix strengthening as a result of increasing dislocation and twin densities, as well as introducing a convenient preferential orientation (texture). In this work we identify and quantify the present phases, and analyze the microstructure of an Fe-15Mn-5Si-9Cr-5Ni mass % (nominal composition) shape memory alloy (SMA) in two states: (1) hot-rolled at 1000 and 800 °C in successive passes with a 10 % rolling reduction per pass, to 1 mm final thickness, and recovery annealed at 650 °C for 30 min; and (2) tensile tested to 4.6 % final strain. In both cases the material characterization was done by X-ray diffraction (XRD) and Rietveld refinement using Maud, and by Electron Backscatter Diffraction (EBSD). We discuss and correlate the experimental results obtained by both techniques.