Microstructure of two-phase Al–1.7 at% Cu alloy deformed by equal-channel angular pressing Original Research Article

The microstructural changes of an aged Al–1.7 at% Cu alloy associated with severe plastic deformation have been studied by transmission electron microscopy (TEM) and energy-filtered transmission electron microscopy (EF-TEM). θ′ precipitates are almost completely dissolved after eight passes of equal-channel angular (ECA) pressing, and nearly single-phase α with a fine grain size of approximately 500 nm is obtained. When a severely deformed sample is aged for 24 h at 100°C, precipitation of equiaxed θ phase is observed along the grain boundaries, whereas only GP zones are formed in the undeformed sample. The dissolution and precipitation processes in severely deformed Al–1.7 at% Cu alloy have been examined by TEM and energy-filter mapping.