Cu-based shape memory alloys are a promising alternative to the widely used nitinol. The challenge for their use is related to the application temperature, shape memory properties as well as fabrication, and further processing. Knowledge of the transformation temperatures, microstructure, and deformation behavior is of fundamental importance. Research suggested that Cu-Al-Mn shape memory alloys could fulfill this combination of properties excellent.
For this purpose, a Cu-Al-Mn-Ni shape memory alloy was melted, cast, and the produced cast rods were subsequently heat treated. For a first idea of whether the chosen composition is a promising alloy depending on the homogenization time, the transformation temperatures and the resulting microstructure were investigated. The transformation behavior was determined by dynamic differential calorimetry. Microstructure investigations were performed by optical microscopy. In addition, to get a first knowledge concerning the deformation behavior the material was characterized by quasi-static compression tests. To this end, cylindrical specimens were turned from the cast bars.
The investigation demonstrates a pseudoelastic behavior of the chosen Cu-Al-Mn-Ni shape memory alloy. The study proves the influence of the homogenization time on the microstructure. Furthermore, excellent deformation behavior and good shape memory properties under compressive loading are shown.