Effect of the intermediate action of hydrostatic pressure on the high-temperature creep and durability of copper

The intermediate action of hydrostatic pressure on the high-temperature creep of copper is studied at various creep stages. Tests performed at a constant tensile stress of 12.5 MPa at 773 K show that the application of a pressure at the creep third stage decreases the steady-state creep rate and extends the time to failure. At the steady-state stage of creep, the effect of the pressure may be ignored. At pressures of up to 1 GPa, this effect is found to be only related to healing of grain-boundary porosity. At higher pressures, the steady-state creep rate is governed by porosity healing and structural changes.