Abstract
It is hoped that shape memory alloys (SMAs) can serve as useful materials in cold regions of the earth. It is necessary to find a means to control the shift of these alloys at temperatures lower than atmospheric temperatures.
Cupper alloys are suitable materials for controlling the constituent elements and easily treating the sampling condition.
Improvements in the characteristics of these alloys have been performed, and these advances are demonstrated in this report.
The main results can be summarized as follows: (1) When the thickness of specimen became thiner, it was clarified that the width of the hysteresis curve of load and temperature increased. This occurs due to the thermal conductivities for shape memory reactions of the specimens. (2) The effect of shape memory behavior on saddle shape specimens was revealed under lower ice-forming temperatures as increasing the slope of load/°C in the hysteresis curve of load and temperature. (3) By adding Ti to a Cu-Al-Ni alloy and B and Celements to a Cu-Al-Ni-Ti alloy, it was recognized that the fracture strength of the alloy had increased and operation temperature of the shape memory behavior had shifted to a lower temperature.
