Characterization of a CuAlBe Alloy with Different Cr Contents

In this article, the use of chromium (Cr) as a grain refiner for a CuAlBe shape memory alloy is discussed. Alloys with 0.1, 0.2, 0.3, and 0.5 wt.% Cr were characterized by optical microscopy, scanning electron microscope, and x-ray diffraction. Also, the influence of the different percentages of Cr on the grain size and on the mechanical properties was analyzed through macro- and microscopic evaluations and by tensile and hardness tests, respectively. Finally, the phase transformation temperatures of the alloys were determined by thermal analysis using differential scanning calorimetry. The results showed that the higher the Cr content, the greater the grain refinement effect and lower the hardness. In addition, at room temperature the alloys with 0.1 and 0.2 wt.% Cr were austenitic, while the rest were martensitic. The tensile tests showed that the alloy with 0.2 wt.% Cr provided the best strain-stress performance. The conclusion was that the use of 0.2 wt.% Cr as a grain refiner improved the mechanical properties of the CuAlBe alloy; however, the same was not observed for the other Cr contents.