Improving creep property of Mg–Gd–Zn alloy via trace Ca addition

Abstract Only trace Ca addition to the Mg–2Gd–0.5Zn–0.2Zr (at.%) alloy leads to the precipitation of Guinier-Preston (GP) zones and remarkably improves the creep resistance at elevated temperatures. The Mg–2Gd–0.5Zn–0.4Ca–0.2Zr alloy exhibits a minimum creep rate of 5.75 × 10 − 8  s − 1 tested at 250 °C and 110 MPa, its superior creep resistance is attributed to the precipitation of dense GP zones on the basal plane, increment in number density of refined β phases on the prismatic plane of the α-Mg matrix, narrow precipitate free zones (PFZs) and strengthened long period stacking ordered (LPSO) phases by trace concentration of Ca.