Conjoint influence of equal channel angular pressing and annealing on microstructure and mechanical properties of aluminum alloy 7075 Gemeinsamer Einfluss des Gleichkanal-Winkelpressens und des Glühens auf das Gefüge und die mechanischen Eigenschaften der Aluminiumlegierung EN AW-AlZn5,5MgCu

Abstract

The effect of equal channel angular pressing combined with inter-pass and post-process annealing on the microstructure and mechanical properties of the Al-7075 alloy has been studied. The samples underwent successful equal channel angular pressing for three passes using the B_c route. The most significant changes in mechanical properties were observed after the first pass. Despite an 88 % reduction in grain size, the hardness of the alloy increased by 45 % and the fracture toughness decreased by 75 %. Post-process annealing was found to be an effective method for enhancing the alloy‘s toughness. Annealing the one-pass sample at 310 °C resulted in a 33 % increase in fracture toughness; from 15.8 J to 21.02 J. Inter-pass annealing had a lesser impact on improving fracture toughness compared to post-process annealing. It can be concluded that a balanced combination of strength and toughness can be achieved by utilizing a combination of equal channel angular pressing and inter-pass or post-process annealing. Examination of the fracture surfaces of the samples revealed intragranular fractures, with the annealed samples exhibiting higher energy absorption during impact and better toughness compared to the non-annealed sample.