Microstructure evolution of the hot-rolled modified AA 5083 alloys during the two stage thermal treatment

Abstract

The effects of the two stage heat treatment on the structure of two hot-rolled 5083 aluminum alloys without and with 0.12% Zr addition were investigated. Combination of the metallographic and transmission electron microscopy (TEM) was carried on in order characterize grain structure as well as precipitates type and morphology. During the homogenization annealing recovery processes and grain structure polygonization were accomplished. Further annealing at the 460°C had little effect on the grain morphology. Two populations of the Mn-based secondary phases were identified: coarser particles containing Fe, while the Mn particles alloyed with Cr were finer. Zr did not precipitate in a form of the fine, coherent precipitate. However, in the alloy containing Zr the recovery appear to be easier and more advanced than in the other alloy.