Research on Natural Aging Behavior of High Purity Ag Sheets After Severe Plastic Deformation

摘要

High purity silver (Ag) powder was melted in vacuum at ~ 10~(-3) Pa and in an atmosphere with charcoal dust as a protective agent. Both samples were subjected to accumulative rolling with 95% thickness reduction and naturally aged for 1 year. The mechanical properties and microstructural studies of as melted and processed samples were evaluated. Results showed that after natural ageing for a year the sample melted in vacuum was responsible for total recrystallization and the sample melted in atmospheric conditions showed slight recovery. It is suggested that grain growth and rotation of Ag is hampered by some oxygen interstitial solute and a few of Ag_2O particles which can keep the orientation of Ag grains stable and obviously resist natural aging and softening.