Isochronal Annealing Behavior of Magnesium Alloy AZ31 after Hot Deformation

Abstract

Annealing behaviors of hot-deformed magnesium alloy AZ31 were studied at temperatures of 373 to 673 K by optical and SEM/EBSD metallographic observation. The hot-deformed alloy had fine-grained structures developed by grain fragmentation due to continuous dynamic recrystallization (cDRX). Temperature dependence of the average grain size (D) is categorized into three temperature regions, i.e. (a) an incubation period for grain growth at < 450 K, (b) rapid grain coarsening at 473-523 K, and (c) normal grain growth at T > 550 K. The number of fine grains per unit area, however, is reduced remarkably even in region (a). These lead to grain coarsening taking place continuously in the whole temperature regions. In contrast, the deformation texture scarcely changes even after full annealing at high temperatures. It is concluded that the annealing processes operating in hot-deformed magnesium alloy with cDRXed grain structures can be mainly controlled by grain coarsening accompanied with no texture change, that is continuous static recrystallization (cSRX).

New schemes of forging plates, shafts, and discs

“…These parameters depend on the chemical composition and microstructure of the product material. The usual process used to affect metal microstructure is heat treatment, but plastic deformation has a significant influence also, confirmed by numerous investigations [1][2][3][4][5][6][7][8]. Plastic deformation, under certain conditions can influence metal grain size and the distribution of carbide and other nonmetallic inclusions.…”

Annealing behaviour of Mg–3Al–1Zn alloy sheet obtained by a combination of high-temperature rolling and subsequent warm rolling

“…In contrast, little work has been done on static recrystallization (SRX) during annealing after deformation especially on the texture evolution and elucidation of the mechanism of SRX in wrought Mg alloys. The lack of information on SRX may be related to the fact that the basal texture, which is detrimental to formability, cannot be changed markedly by annealing, in most cases [3][4][5][6][7][8][9][10][11][12]. The final annealing texture is dominated by primary recrystallization and grain growth.…”

“…In addition, recrystallization and particularly grain growth tend to result in a single peak replacing a double peak in the basal pole during annealing [5,7]. Yang et al [3,4] reported that annealing mainly results in grain coarsening accompanied by a scarcely changed texture, i.e. continuous SRX, in the case of hot deformed Mg-3Al-1Zn (AZ31) alloy with a continuous DRXed microstructure.…”

Influence of initial texture on rolling and annealing textures of Mg–3Al–1Zn alloy sheets processed by high temperature rolling

“…Therefore, it is desirable to achieve a weakened texture with tilted basal poles. A great effort has been devoted to texture modification, however, the strong basal texture cannot be changed markedly by annealing in most cases [6][7][8][9][10][11][12][13][14][15]. In addition, annealing tends to result in a single peak replacing a double peak in the basal pole [8,10], even though the double peak may lead to an enhanced formability [16].…”