On the Damping Property of Cu-Al-Ni Sintered Alloys

Abstract

Regardless of Ni contents in slack-quenching Cu-14 wt%Al-Ni sintered specimens, we obtained a maximum value of the internal friction at about 50°C in their heating curves, where Q30°C^-1 obtained at 30°C always amounts to about 80% of Q50°C^-1 and the concentration dependency of Q30°C^-1 coincides with that of Q50°C^-1.
The results obtained were as follows:
(1) The maximum value of Q30°C^-1 of Cu-Al-4 wt%Ni and Cu-Al-8 wt%Ni sintered alloys with different Al contents were found around 14 wt%Al in both the cases.
(2) Q30°C^-1 of Cu-14wt%Al-Ni sintered alloys increased up to 6 wt%Ni, kept the maximum value constantly between 6 and 9 wt%Ni, and decreased over than 9 wt%Ni.
(3) Judging from the X-ray diffraction patterns, we confirmed that the height of the above-mentioned convex curve corresponds to the quantity of γ' martensite, where the slack-quenching Cu-14 wt%Al-8 wt%Ni sintered alloy composed of only single phase of γ' martensite shows the maximum value of Q30°C^-1.