Creep rupture properties of die-cast Mg–Al–Ca alloys

Creep rupture tests were performed for die-cast AM50 + xCa (x = 0, 0.47, 0.95 and 1.72 mass pct) alloys at temperatures between 423 and 498 K. The creep curve for the alloys is characterized by a minimum in the creep rate, and the decrease in creep rate during transient stage becomes pronounced with calcium concentration. The minimum creep rate (ε˙m) and the creep rupture life (trup) follow the phenomenological Monkman–Grant relationship for each alloy; trup=C0/ε˙mm. It is found that the exponent m is unity for the alloys and the constant C0 is independent of creep testing temperature, which is reduced with increasing calcium concentration.