On applying superplastic Zn-22 wt.% Al alloy with nanocrystalline grains to general residential seismic dampers

Recently, a superplastic damping device, which is using Zn-22 wt.% Al alloys with an ultra-fine (nanometer order) grain size, has been put into practical use for a high-rise building. For the purpose of the development and mass-production of the damping devices for a general residence, we carried out an investigation about the design of the most appropriate damperʹs shape and the capability of superplastic forming. According to the results of a finite volume method analysis, the higher stress and strain at both sides of the inferior part of the gauge section were observed, but the strain was relatively small. No deterioration of mechanical properties due to the grain growth and cavitation during the forging was observed after the forging.