Loading rate and temperature dependency of superelastic Cu–Al–Mn alloys

This paper presents results from recent experiments performed on superelastic Cu–Al–Mn alloy bars (rods) with different diameters under various loading rates and temperatures. Previously, Araki et al. [2] tested the rate-dependent response of 8 mm bars up to 1 Hz loading rate. In this paper, loading rate (up to 15 Hz) and temperature (−40 to 50 °C) dependency of three different bar diameters (8, 12 and 16 mm) was investigated. In addition, the cyclic behavior under large tensile strains (up to 14%) was studied. The motivation for this study was to investigate test parameter ranges that were not explored before (i.e., loading rate, temperature and bar diameter) and to determine the suitability of superelastic Cu–Al–Mn alloys for use in full-scale structures subjected to earthquakes. The ranges for loading rate and temperature as well as the bar diameter were selected with these objectives in mind. It was observed that all Cu–Al–Mn bars show excellent superelastic behavior up to 12% strain under a wide range of loading rates and temperatures. Microstructural analysis of the Cu–Al–Mn alloy bars indicates that the control of texture as well as the relative grain size is important for obtaining stable superelasticity.