Rate-dependent response of superelastic Cu–Al–Mn alloy rods to tensile cyclic loads

Abstract

We report the results of tensile cyclic loading tests conducted to examine the dependence of constitutive relations for superelastic Cu–Al–Mn alloy rods on loading rates. Recently, Cu–Al–Mn alloy rods with diameters up to 8 mm have been developed by the authors, and it has been demonstrated that these rods have excellent superelastic strains of more than 8%, which is comparable to Ni–Ti alloys and far superior to other Cu-based alloys. No information is available, however, on the rate dependence of constitutive relations for Cu–Al–Mn alloys. In this study, we prepare two Cu–Al–Mn alloy rod specimens, whose lengths and diameters are 150 mm and 8 mm, respectively. Their stress–strain relations are examined under the loading frequencies of 0.001, 0.5, and 1 Hz with constant strain amplitude of 4.5%. It was found from the tests that the maximum stress increase in Cu–Al–Mn alloys due to higher loading rate was less than 5%. Thermo-mechanical analysis predicts that stress increase in Cu–Al–Mn alloys is about 1/4 of that in Ni–Ti alloys, which agrees reasonably well with the experimental observations. Such low stress increase is highly desirable in the design of seismic devices such as dampers and isolators.

Laser welding of Cu-Al-Be shape memory alloys: Microstructure and mechanical properties

“…Cu-based shape memory alloys have potential applications as seismic devices for energy absorption [42,43]. However, for these materials to be used in such applications it is necessary that the superelastic behaviour is stable for a wide range of temperatures [44], below −10°C and up to 50°C, ideally.…”

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

“…These grain structures with a relatively large grain size are favorable for superelasticity. Another important factor is the crystallographic orientation because the transformation strain is greatly anisotropic in Cu-Al-Mn alloys (Araki et al, 2012). The crystallographic orientation of each grain in Specimens A, B, C and D is shown in Figure 6(b), where the solid and open circles show the orientation along the tensile loading direction of large and small grains, respectively.…”

“…It is known, however, that the superelasticity of Cu-Al-Be alloys is about half that of Ni-Ti alloys. On the other hand, Araki et al (2012) investigated the rate dependency and superelastic performance of Cu-Al-Mn alloy bars of 8 mm diameter up to 1 Hz loading rate, and found that the rate-dependency was about 1/4 that of Ni-Ti alloys while superelasticity was comparable to Ni-Ti alloys (Araki et al, 2011). Sutou et al (2009) and Niitsu et al (2011) studied temperature dependency of Cu-Al-Mn wires of 1 and 2 mm diameter, respectively, and found that the temperature dependency was less than half that of Ni-Ti alloys.…”

Study of SMA-dowelled timber connection reinforced by densified veneer wood under cyclic loading

“…The SMA utilising in this study is Cu-Al-Mn SMA provided by Shinko Metal Product Co., LTD, Japan. Araki et al [13] and Huang [14] stated that Cu-Al-Mn SMA has a large recovery strain and fracture strain, and the low-cycle fatigue of Cu-Al-Mn SMA was found to be superior. According to Araki et al [15], copper-based SMA is less expensive than NiTi SMA, and the Cu-Al-Mn alloy is the cheapest and even more inexpensive than other copper-based SMAs.…”