Damping Characteristics of Inherent and Intrinsic Internal Friction of Cu-Zn-Al Shape Memory Alloys
نویسندگان
چکیده
Damping properties of the inherent and intrinsic internal friction peaks (IFPT + IFI) of Cu-xZn-11Al (x = 7.0, 7.5, 8.0, 8.5, and 9.0 wt. %) shape memory alloys (SMAs) were investigated by using dynamic mechanical analysis. The Cu-7.5Zn-11Al, Cu-8.0Zn-11Al, and Cu-8.5Zn-11Al SMAs with (IFPT + IFI)β3(L21)→γ′ 3(2H) peaks exhibit higher damping capacity than the Cu-7.0Zn-11Al SMA with a (IFPT + IFI)β3(L21)→γ′ 3(2H) peak, because the γ ′ 3 martensite phase possesses a 2H type structure with abundant movable twin boundaries, while the β3 phase possesses an 18R structure with stacking faults. The Cu-9.0Zn-11Al SMA also possesses a (IFPT + IFI)β3(L21)→γ′ 3(2H) peak but exhibits low damping capacity because the formation of γ phase precipitates inhibits martensitic transformation. The Cu-8.0Zn-11Al SMA was found to be a promising candidate for practical high-damping applications because of its high (IFPT + IFI) peak with tan δ > 0.05 around room temperature.
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