T. Omori, Y. Sutou, N. Koeda, R. Kainuma, K. Ishida, Tohoku University, Sendai, Japan
Shape memory alloys are known as materials that have high damping capacity in the martensite phase. The present authors reported that Cu-Al-Mn shape memory alloys show high cold-workability by degreasing the degree of order in the β (bcc) phase. Many varieties of microstructural control can be applied to the Cu-Al-Mn-base alloys because of the ductility, which causes a drastic enhancement of the shape memory properties. Particularly, it has been demonstrated that texture control is considerably effective for the improvement of the shape memory properties, therefore, it is expected that the damping properties are enhanced by the texture control. In this study, the effect of the texture on the damping properties was investigated in the Cu-Al-Mn-Ni alloys using DMS (Dynamic Mechanical Spectrometry) technique. A recrystallization texture {112}<110> was developed by a thermomechanical processing, which is a combination of annealing at 600ºC in the α (fcc) + β two-phase region followed by cold-rolling and subsequent solution-treatment at 900°C in the Cu-Al-Mn-Ni alloys. It was found that the damping properties are dependent on the loading direction and an excellent damping capacity of tanΦ = 0.1 was obtained in the martensite phase with a tensile strength of 600MPa in Cu71.3Al17Mn8.7Ni3 alloy. The high strength damping alloys possessing a tensile strength of 870MPa was also obtained by microstructural controls of the texture and precipitation.
Summary: The effect of the texture on the damping properties was investigated in the ductile Cu-Al-Mn-Ni shape memory alloys. A recrystallization texture {112}<110> was developed by a thermomechanical processing. It was found that an excellent damping capacity of tanΦ = 0.1 was obtained in the martensite phase with a tensile strength of 600MPa, and the high strength damping alloys possessing a tensile strength of 870MPa was also obtained by microstructural controls.
