Evolution of the stress-induced martensitic transformation in a CuAlBe shape memory alloy under uniaxial tension, pp. 247-265
Authors: F. M. Sánchez-Arévalo, G. Pulos, R. Pérez-Cabeza de Vaca
Abstract: The evolution of the stress-induced martensitic transformation was determined for a Cu-Al 11.2 wt%-Be 0.6 wt% shape memory alloy by digital image analysis. The CuAlBe tensile specimens were subjected to uniaxial tension; during the tension test, digital images of the polished and chemically etched surface‘s specimens were taken. From the tension test, the stress-strain curve representing the macromechanical behavior of the material was obtained. From the acquired images, the stress-induced martensitic transformation was observed and the number of grains, the area of the grains and the martensitic plates in the grains were estimated. Additionally, the orientation of the martensitic plates was determined for each image associated to the stress-strain curve. Image analysis showed that, during the tension test, the martensitic variants appeared and disappeared due to the interaction between a grain and its neighbors, which is caused by the stress state of the grain, the original variant or variants, and the state of transformation of the neighboring grains. With the results from the micromechanical behavior, the strain measured with the strain gage could be resolved into its elastic and transformational components.