Masakatsu Hinai1, Showhachi Sawaya1 and Hakaru Masumoto1
1The Research Institute for Electric and Magnetic Materials, Yagiyama-Minami 2, Sendai 982
The logarithmic decrement δ and the rigidity modulus G were investigated for heat-treated and cold-worked Al-Ge alloys containing 2 to 20 mass%Ge. The δ and G values were measured by an inverted torsion pendulum method.
The δ values upon furnace cooling were somewhat higher than those upon water quenching, which were as low as 0.007. By cold working after heat treatment, the δ values of all alloys were increased considerably. With increasing Ge concentration, the δ upon cold working increased abruptly to 5 mass%Ge and then increased gradually. Moreover, in alloys cold worked after furnace cooling, the δ became higher than those cold-worked after water quenching.
With increasing Ge concentration, the G increased, and cold working after heat treatment caused G to decrease. The Δ G effect increased abruptly up to 5 mass%Ge and then increased gradually, and high δ values were obtained in the alloys with a large Δ G effect.
damping capacity, logarithmic decrement, high damping alloy, dislocation, aluminium-germanium alloy, Δ G effect, rigidity modulus, cold worked alloy.
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