Influence of texture on the recrystallization mechanisms in an AZ31 Mg sheet alloy at dynamic rates

Abstract

An AZ31 rolled sheet alloy has been tested at dynamic strain rates (e~10 3 s _1 ) at 250°C up to various intermediate strains before failure in order to investigate the predominant deformation and restoration mechanisms. In particular, tests have been carried out in compression along the rolling direction (RD), in tension along the RD and in compression along the normal direction (ND). It has been found that dynamic recrystallization (DRX) takes place despite the limited diffusion taking place under the high strain rates investigated. The DRX mechanisms and kinetics depend on the operative deformation mechanisms and thus vary for different loading modes (tension, compression) as well as for different relative orientations between the loading axis and the c-axes of the grains. In particular, DRX is enhanced by the operation of (c + a) slip, since cross-slip and climb take place more readily than for other slip systems, and thus the formation of high angle boundaries is easier. DRX is also clearly promoted by twinning.

Anisotropy of the Mechanical Properties of Twin-roll Cast, Rolled and Heat-treated AZ31 as a Function of Temperature and Strain rate

“…A theoretical connection of the texture (evolution) with the material behaviour was interpreted from [5,9,10,19,24,[38][39][40][41]. The yield strength is a function of the initial texture [24].…”

“…An enhancement of the dislocation motion in the 0° deformation direction compared to the 90° direction led to dynamic recovery followed by increased dynamic recrystallization [39]. This became apparent through lower strain hardening in the flow curves [40]. In addition, grain boundary sliding could occur [41].…”

Grain size dependence of dynamic mechanical behavior of AZ31B magnesium alloy sheet under compressive shock loading

“…It should be mentioned that so far, the studies that have been conducted on the effect of grain size on the mechanical behavior of AZ31B magnesium alloys have been focused on the low strain rate conditions [11][12][13][14][15][16][17][18][19][20][21][22]. Besides, in the available reports in the literature on the high strain-rate deformation of AZ31B alloys [23][24][25][26][27][28][29][30], the effect of grain size is not investigated and there is a considerable knowledge gap in the correlation between the grain size and dynamic impact response of AZ31B magnesium alloys.…”

Transient x-ray diffraction with simultaneous imaging under high strain-rate loading

“…Measurements exhibiting similar deformation and failure features were obtained previously. [19][20][21][22] The strain maps E eq (x, y) for sample #AZ31-17 exhibit four stages of deformation ( Fig. 6): elastic deformation (t 1 -t 2 ), "inhomogeneous" plastic deformation (t 3 -t 5 ), homogenization of plastic deformation (t 6 -t 8 ), and shear failure (t 9 -t 10 ).…”