The creep performance of a sand-cast Mg-2.8Nd-0.8Zn-0.5Zr-0.3Gd alloy at 241 to 262 °C

Secondary creep rates of sand-cast Mg - 2.8 Nd - 0.8 Zn - 0.5 Zr - 0.3 Gd (wt.%) alloy at 242.5 +/- 1.5 degreesC and 40 to 90 MPa applied tensile stress are shown to be a factor of similar to 24 smaller than reported earlier for chill-cast Mg - 2.4 Nd - 0.4 Zn - 0.3 Mn at 240degreesC. The relative contributions of grain/cell size and of alloying in achieving this improved creep resistance are discussed. Additionally, preliminary results at 248 and 262 degreesC indicate an activation energy for creep somewhat larger than that for the earlier alloy at 150 to 240 degreesC and that for lattice self-diffusion in magnesium.