Damping Capacity of Composite Sheets Made by Superplastic Rolling/Joining Technique of Steel-Superplastic Alloy

Abstract

A study has been conducted to develop the composite sheets made by superplastic rolling/joining technique of steel-superplastic alloys which could be used for the damping material at high temperature. The superplastic alloys used were Zn-22%Al alloy, Al-6%Cu-0.5%Zr alloy and Al-12.9%Mg₂Si alloy and the composite sheets consisted of the three layers of steel and superplastic alloy (e. g. steel-s. p. alloy-steel, s. p. alloy-steel-s. p. alloy). In case of Zn-22%Al alloy, the volume percentage of the alloy was changed at five steps of 0, 25, 50, 75 and 100%. The specimens were rolled at 4 or 5 passes at 200°C and the final reduction became 80%. The laminar and granular structures could be obtained by heat treatments after rolling. In case of the other alloys, the volume percentage of the alloys was 50%. The specimens were rolled at 300°C and the final reduction became 80%. The results obtained were as follows;
(1) The damping capacity of the steel-Zn-22%Al alloy composite sheet could be obtained several times values of the steel in room temperature. The damping capacity increased with increasing temperature. Above the temperature of 200°C, the damping capacity exceeded 0.1.
(2) In the composite sheets of steel-Al superplastic alloys, good formability could be obtained by heat treatment.