Strengthening of AA7075 alloy by processing with high-pressure sliding (HPS) and subsequent aging

High-pressure sliding (HPS) is a new severe plastic deformation process for sheet samples under high-pressure. In this study, the HPS process is applied to an age-hardenable 7075 aluminum alloy for grain refinement. HPS was conducted under a pressure of 1.0 GPa for sliding distances of 7.0 mm at room temperature and for 10 mm at 373 K and 423 K, and thus the average grain size was reduced to ~280 nm, ~240 nm and ~250 nm. Ultimate tensile strength of ~600 MPa was achieved by this grain refinement. Aging at 373 K led to further hardening to 745 MPa of ultimate tensile strength with 4% of elongation to fracture through a fine dispersion of precipitates. It is shown that simultaneous strengthening due to grain refinement and fine precipitation is achieved in the AA7075 by application of HPS and subsequent aging.