2007 Volume 48 Issue 3 Pages 510-514
The microstructural features of Al-Cu 2218 alloy after FSP were composed mainly of equiaxed 4 μm grains as well as a much more random orientation in SZ comparing to the extruded base metal. In this investigation, tensile properties of FSP specimens displayed an advanced performance than base metal. Furthermore, it should be noted that the FSP specimens possessed great elongation which even more than 100% at 400 °C. As the test temperature over 450 °C, the deterioration of the elongation could be responsible to second phase particles coarsening during tensile deformation process as well as abnormal grain growth. Ductility was commonly degenerated in both base metal and FSP specimens at 500 °C, whole grains within FSP sample grew into large ones that conducted the seriously descent of ductility. It is rational to deduce that the tensile strain promoted the coarsening of particles that would resulted from Ostwald ripening phenomenon. The declination of elongation could be ascribed mainly to the microstructural stability problem at elevated temperature.
