Absorbable magnesium alloy

A magnesium alloy consisting, by weight percent: 0.5 to 8.0 percent ytterbium; 0.1 to 2.0 percent calcium; and 0.2 to 6.0 percent zinc; and optionally up to 4.0 percent scandium; up to 2.0 percent of yttrium; 0.05 to 1.0 percent manganese; up to 1.0 percent zirconium; and up to 2.0 percent aluminum, wherein the balance up to 100% by weight is magnesium.