Effects of hot forming cold die quenching and inter-pass solution treatment on the evolution of microstructure and mechanical properties of AA2024 aluminum alloy after equal channel angular pressing

Abstract

The aim of this research is to investigate the effect of hot forming cold die quenching (HFQ) equal channel angular pressing (ECAP) on the microstructural evolution and mechanical properties of AA2024 aluminum alloy. For this purpose, solution treated AA2024 aluminum alloy was initially ECAPed in HFQ and water quenched (WQ). Microstructural evolutions, dislocation density, and mechanical properties were investigated after up to 3 (WQ-ECAP) and 5 (HFQ-ECAP) passes of deformation. Intermediate solution treatment was conducted after each ECAP pass. The samples underwent aging treatment after deformation. Large amount of shear banding was observed in samples after the first ECAP pass which was reduced in the successive passes of ECAP through intermediate solution treatment. Tensile properties and microhardness enhanced by increasing number of ECAP passes. However; after the fifth pass of HFQ-ECAP, sudden decrease in mechanical properties was observed. Partial decomposition of supersaturated solid solution was found to occur at higher strains. Mechanical properties and deformability were improved in the HFQ-ECAP samples with respect to WQ-ECAP.