A magnesium-based alloy consists of 1.5-4.0% by weight rare earth element(s), 0.3-0.8% by weight zinc, 0.02-0.1% by weight aluminum, and 4-25 ppm beryllium. The alloy optionally contains up to 0.2% by weight zirconium, 0.3% by weight manganese, 0.5% by weight yttrium and 0.1% by weight calcium. The remainder of the alloy is magnesium except for incidental impurities.