Microstructures and mechanical properties of Mg-Gd-Zn-Zr alloys prepared by spark plasma sintering.

Two Mg-Gd-Zn-Zr alloys (GZ100K and GZ122K) with Gd/Zn atomic ratios of 24 and 3 were prepared by spark plasma sintering (SPS) and the effect of sintering temperature on microstructures and mechanical properties of these two alloys was systematically investigated. With increasing sintering temperature, the volume fraction of β-(Mg,Zn) 3 Gd phase decreases accompanied with the grain size increasing. Besides, the normal grain growth turns into abnormal grain growth in the as-sintered GZ100K when the sintering temperature increases to 440 °C. A 14H long-period stacking ordered (LPSO) phase forms in the as-sintered GZ122K at 440–480 °C, which can delay grain coarsening. The GZ122K alloy sintered at 400 °C achieves ultimate compressive stress (UCS) of 410 MPa and yield stress (CYS) of 222 MPa. While, the GZ100K alloy sintered at 400 °C reaches the highest UCS of 386 MPa and CYS of 210 MPa. Compared with the as-cast counterparts, the increment in strength of as-sintered alloys is mainly due to grain boundary strengthening arising from the fine grains produced by SPS. • Two Mg-Gd-Zn-Zr alloys with different Gd/Zn ratios were first fabricated by SPS. • The formation of 14H-LPSO phase in GZ122K can delay the grain growth. • GZ122K and GZ100K alloys achieve maximum compressive strength sintered at 400 °C. [ABSTRACT FROM AUTHOR]