Microstructure development during extrusion in a wrought Mg–Zn–Zr alloy

Effect of Ag on interfacial segregation in Mg–Gd–Y–(Ag)–Zr alloy

“…Fig. 5f indicates that Zr was not segregated either, which is consistent with a literature report [41]. comparisons, the same grain boundary angle of $144°is chosen for comparison in both alloys.…”

The role of Zr-rich cores in strength differential effect in an extruded Mg–Zn–Zr alloy

“…An earlier study by the same authors has shown that microstructure of the alloy in DC-cast condition contains Zr-rich cores within the grains where the concentration of Zr is over 1 wt.% [5]. Other microstructural features of the alloy are Zn-rich rings at the grain boundaries, some Mg-Zn eutectic constituents and the Zn-Zr intermetalics [5]. In addition to grain refinement, Zr addition enhances the homogeneity of the microstructure by making the grains round, and reduces the amount of eutectic at the grain boundaries, so that more Zn can go in the solid solution and contribute in strength [4].…”

“…An earlier study by the same authors has shown that Zr concentration in these cores is in the range 1-1.4 wt.% [5] which is much higher than the solubility limit of Zr in Mg at room temperature [14]. After deformation, these cores exhibit poor recrystallization behavior and depending upon the deformation conditions, some of the cores do not recrystallize and remain as deformed structures.…”

“…Changes in c/a ratio can alter the planar and directional densities and thus influence the activation of various slip systems and deformation twinning. It seems that in Zr-rich cores, which have much higher Zr concentration (1-1.4 wt.%) in comparison to the immediate neighborhood (0.1-0.3 wt.%) [5], the limited activation of c + a pyramidal slip and deformation twinning makes the deformation inhomogeneous and results in grain curling. FEM simulations indicate that the absence of pyramidal slip in Mg alloys causes curling of the grains [23].…”

“…The initial solid solution formed around Zr particles has much higher Zr concentration than its immediate neighborhood and these regions are usually referred as Zr-rich cores [4]. An earlier study by the same authors has shown that microstructure of the alloy in DC-cast condition contains Zr-rich cores within the grains where the concentration of Zr is over 1 wt.% [5]. Other microstructural features of the alloy are Zn-rich rings at the grain boundaries, some Mg-Zn eutectic constituents and the Zn-Zr intermetalics [5].…”