Improvement of Mechanical Properties of 7475 Aluminium Alloy by the Combination of SPD Processing and Annealing
In the present study, SPD processing was combined with annealing in order to obtain synergic effect of grain size refinement and precipitate strengthening. Samples of 7475 alloy were solution heat treated, water quenched and then subjected to hydrostatic extrusion with a total true strain of about 4. Hydrostatic extrusion resulted in a significant grain refinement from 70 mm to about 70 nm. The samples were subsequently annealed at temperatures inducing the formation of nano-precipitates. The investigations of the structure and mechanical properties of the samples subjected to SPD and annealing revealed different precipitation path in micro- and nano-grained samples. Also, it was found that the combination of HE processing and low temperature annealing results in the formation of nano-precipitates in nano-grained structures which effectively strengthen nano-aluminium alloy.
Hajo Dieringa, Norbert Hort and Karl Ulrich Kainer
K. Wawer et al., "Improvement of Mechanical Properties of 7475 Aluminium Alloy by the Combination of SPD Processing and Annealing", Materials Science Forum, Vol. 690, pp. 311-314, 2011