Improving microstructure and ductility in the Mg–Zn alloy system by combinational Ce–Ca microalloying

Development of high-strength, low-cost wrought Mg–2.5mass% Zn alloy through micro-alloying with Ca and La

“…Extrusion and the subsequent cooling process at temperatures lower than homogenization, accompanying with the large deformation caused by the extrusion, lead Ca and Zn to precipitate in the form of Ca 2 Mg 6 Zn 3 . Similar fine Ca 2 Mg 6 Zn 3 particles precipitating in Mg-4Zn-0.3Ca-0.1Ce alloy were reported [14]. Additionally, the number of fine Ca 2 Mg 6 Zn 3 particles in the Mg-4Zn-0.3Ca-0.1Ce alloy is much higher than that of the Ce-free Mg-4Zn-0.3Ca alloy, which indicates that Ce in Ref.…”

“…5a and b). Such densely-dispersed precipitates were not observed in an extruded Mg-Zn alloy containing similar Zn content, such as the Mg-2.7Zn alloy [48] and the Mg-4Zn alloy [14]. The fact that the addition of Ca and La promotes precipitation of Ca 2 Mg 6 Zn 3 in Mg-Zn alloy is straightforward.…”

“…In Mg alloys, Mg-Al and Mg-Zn alloys are promising candidates for the base alloys to be microalloyed as low-cost, high-strength Mg alloys due to high solubility of Al and Zn in Mg at elevated temperatures and ability of forming coherent and semi-coherent metastable intermetallics at room temperature [7]. In the Mg-Zn system, many trace elements including Ca, Sr, Ag, Zr, Mn, Y and Ce, have been added singly, doubly and even multiply, such as Mg-4Zn-0.1Ca (all compositions are expressed in mass% in this paper unless otherwise specified) [8], Mg-4.9Zn-0.2Ce [9], Mg-1Zn-0.12Sr [10], Mg-5Zn-0.9Y-0.16Zr [11], Mg-2Zn-0.3Zr-0.9Y [12], Mg-6.18Zn-0.16Ca-0.42Ag [13], Mg-4Zn-0.3Ca-0.1Ce [14], Mg-5.25Zn-0.6Ca-0.3Mn [15], Mg-6Zn-0.2Ca-0.8Zr [16], Mg-6.15Zn-0.42Ag-0.16Ca-0.57Zr [17], Mg-3Zn-0.25Ca-0.5Zr-0.15Mn [18], Mg-3Zn-0.5Ag-0.25Ca-0.15Mn [19] and Mg-3Zn-0.5Ag-0.25Ca-0.15Mn-0.5Zr [19,20]. Trace addition of Ca singly to Mg-Zn alloys causes significant grain refinement during solidification, extrusion and rolling [21], and weakens basal texture of the wrought Mg-Zn alloys [22].…”

“…Zn content in Mg-Zn base alloys reported in literature [8][9][10][11][12][13][14][15][16] usually ranges from 1-8% in mass. Lower content of Zn leads to high ductility but lower strength due to coarser grains and less precipitates [10,30], for instance, Mg-1Zn-0.5Ca [31] possesses YS 120 MPa and UTS 200 MPa after extrusion, which is far less than the strength requirement of structural parts.…”

Mechanical Properties of Magnesium-Rare Earth Alloy Systems: A Review

“…They also reported in [108] that after ageing, precipitates such as Mg24Y5, W-phase and I-phase were formed and affected the tensile properties of Mg-alloys as shown in Table 20. Langelier et al [50] reported that the combined micro alloying of Ce and Ca results in the formation of Mg6Ca2Zn3 particles and MgZnCe T-phase in annealed alloys that limit the texture effects due to their large size and coarse distribution. The improved properties of the alloys are due to the grain boundary pinning by Mg6Ca2Zn3 precipitates.…”