The Effects of Grain Size on Ductility of AZ31 Magnesium Alloy

Abstract

It is well known that the ductility of magnesium and magnesium alloy is too poor to be processed. After normal hot extrusion, the ductility of magnesium alloy will be improved, but not noticeably. In this paper, further extrusion (Extrusion Ratio is 6.25) is adopted to commercial AZ31 magnesium alloy rods (Extrusion Ratio is 2) at different temperatures in order to refine the size of grain, then the rods with the crystallite size between 4-10μm is obtained, and the influence of crystallite with different grain size on the ductility of this alloy is investigated further. A lot of experiments and research indicate that: the elongation of the initial billet with the grain size of 30μ m can reach about 12%; after extrusion at different temperatures, the grain size can be refined to below 10μm, and the ductility goes up to 24%-30%. It also shows that, when the grain size of AZ31 magnesium alloy is below 10μm, the ductility is effected obviously. Only when the grain size is about a few microns, the ductility of AZ31 magnesium alloy will be improved noticeably.

Increasing significantly the failure strain and work of fracture of solidification processed AZ31B using nano-Al2O3 particulates

“…2); and (d) the redistribution of basal plane (0 0 0 1) in the case of nano-composite samples. Grain refinement particularly benefits hexagonal metals in ductility increment [7,23]. In earlier studies Wang et al revealed an increase in ductility up to 30.82% by reducing the grain size to below 5 m. These results are consistent in principle with the results obtained in our study (see Tables 1 and 3).…”

“…This observation is not unique as ductility improvement in AZ31B was also attempted using addition of Mn [11] and Sr [21] and Li [22]. The increase in ductility of AZ31B/Al 2 O 3 formulations can primarily be attributed to: (a) grain refinement [23]; (b) presence and reasonably good distribution of Al 2 O 3 particulates [2]; (c) reduction in size and roundness of second phase (see Table 2 and Fig. 2); and (d) the redistribution of basal plane (0 0 0 1) in the case of nano-composite samples.…”

Effects of zinc, lithium, and indium on the grain size of magnesium

“…[5][6][7] The effect of fine grain size on the ductility of magnesium at room temperature has been observed since the 1960s. [8][9][10][11][12] Observations on coarse-grained material demonstrate an abrupt change in ductility at around 230 C (Fig. 1), while fine-grained structure smoothes out this inflexion.…”

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

“…This is a commercial magnesium alloy with wide application in the automotive and aerospace industries. 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.…”