Characteristic of cavity growth of superplastic al 7475 alloy containing a small amount of liquid

The change in an artificial hole during superplastic flow was measured at 773 and 806 K in AA 7475 Al alloy to investigate the effect of a small amount of liquid on plastic cavity growth during grain boundary sliding, where 773 K was lower than the incipient partial melting temperature and 806 K was slightly above the incipient partial melting temperature. The cavity growth rate at 806 K was lower than that at 773 K, indicating that cavity growth is suppressed by the presence of a small amount of liquid. The low cavity growth rate due to a small amount of liquid is suggested to be attributed to the change in the. stress state at the liquid boundaries.