Masakatsu Hinai1, Showhachi Sawaya1 and Hakaru Masumoto1
1The Research Institute of Electric and Magnetic Alloys, Yagiyama-Minami 2, Sendai 982
The influence of cold working on the damping capacity and the mechanical properties was investigated for Al-Ni alloys containing 0.2 to 12%Ni. The logarithmic decrement δ and the rigidity modulus G were measured by an inverted torsion pendulum method, and the tensile strength σ t by an Instron-typemachine.
In both the furnace-cooled and water-quenched states the δ was increased in some degree by the Ni addition. By cold working after heat treatment, the δ became considerably higher with increasing reduction rate in area. The alloys cold-worked after furnace cooling was higher in δ than those cold-worked after water quenching; the Al-4%Ni alloy showed the highest δ value of 63×10-3 when cold-worked to 95% reduction rate in area. The increment in δ by cold working is considered to be due to a remarkable increase in density of dislocations and an action as pinning of a proper amount of compound Al3Ni (ε phase) on dislocation motion. Cold working after the heat treatment results in a decrease in G and an increase in σ t. The G and σ t both increased with increasing Ni concentration, irrespective of the heat treatment and the cold working that followed.
damping capacity, internal friction, logarithmic decrement, high damping material, aluminum-nickel alloy, cold-worked alloy, rigidity modulus, tensile strength
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