Mechanical Characterization of Cu-Al-based Shape Memory Alloys: Influence of Mn, Be and Fe on Tensile Strength, Yield Stress, Yield Strain, Ductility and Hardness

Abstract

The pursuit of cost-effective and robust Shape Memory Alloys (SMAs) continues to expand, especially for applications in adaptive and smart structural systems, while Ni-Ti-based SMAs remain prevalent due to their superior pseudoelasticity and longevity. However, the limitations of NiTi alloys, including the high processing costs and fabrication difficulties, prompt the exploration of alternatives. This study investigates Cu-Al-based SMAs alloyed with Mn, Be, and Fe as cost-effective alternatives to NiTi systems. In the present work, Cu-Al-based alloy wires with Mn, Be, and Fe were betatized at 850 °C and water-quenched to achieve martensitic structures, followed by evaluation of tensile strength, yield behavior, ductility, and hardness. Mn addition significantly enhanced tensile strength (up to 425 MPa), while Be and Fe improved ductility through grain refinement. Hardness increased with Mn due to solid solution strengthening. Thus, the current work provides a comparative analysis of Cu-Al-Mn, Cu-Al-Be-Mn, and Cu-Al-Fe-Mn alloys, linking alloying strategies to microstructural evolution and mechanical performance, demonstrating their potential for advanced engineering applications.