%0 journal article
%@ 2213-9567
%A Shi, H.,Huang, Y.,Yang, L.,Liu, C.,Dieringa, H.,Lu, C.,Xiao, L.,Willumeit-Römer, R.,Hort, N.

%D 2023
%J Journal of Magnesium and Alloys
%N 
%P 3161-3173 
%R doi:10.1016/j.jma.2023.09.005
%T Microstructural evolution of Mg–14Gd–0.4Zr alloy during compressive creep
%U https://doi.org/10.1016/j.jma.2023.09.005
 
%X The present work reports the creep behavior and microstructural evolution of the sand-cast Mg–14Gd–0.4Zr alloy (wt.%) prepared by the differential pressure casting machine. Their compressive creep tests at 250 °C were performed under various applied stresses (i.e., 60, 80 and 100 MPa). Among them, the sand-cast Mg–14Gd–0.4Zr samples examined under 250 °C/80 MPa for 39 and 95 h, respectively, were chosen to systemically analyze their creep mechanisms using high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). The obtained results showed that the enhancement of creep resistance can be mainly attributed to the coherent β' and β'F phases with an alternate distribution, effectively impeding the basal <a> dislocations movement. However, with the creep time increasing, the fine β'+β'F precipitate chains coarsened and transformed to semi-coherent β1 phase and even to large incoherent β phase (surrounded by precipitate-free areas) in grain interiors. The precipitate-free zones (PFZs) at grain boundaries (GBs) were formed, and they could expand during creep deformation. Apart from the main cross-slip of basal and prismatic <a> dislocations, <c + a> type dislocations were activated and tended to distribute near the GBs. The aforementioned phenomena induced the stress concentrations, consequently leading to the increment of the creep strain.