Biodegradable magnesium alloy

Abstract

A magnesium alloy includes a rare earth element alloy component comprising yttrium, a rare earth element (REE) other than yttrium, and a balance of magnesium. The rare earth element other than yttrium may comprise two or more rare earth elements other than yttrium. The rare earth element other than yttrium may include a heavy rare earth element and a light rare earth element. The alloy may include about 4-10 wt-% yttrium, 0-9 wt-% heavy REE, 0-7 wt-% light REE, 0-7 wt-% zinc, 0-0.7 wt-% zirconium, and a balance of magnesium. The balance of magnesium may be in an amount up to 90 wt-%.

What is claimed is: 
     
         1 . An alloy comprising:
 a rare earth element alloy component in an amount greater than 6 wt-% comprising:
 yttrium in an amount greater than 2 wt-%; and 
 a rare earth element other than yttrium in an amount greater than 1% selected from gadolinium, dysprosium, erbium, neodymium, lanthanum, cerium, and combinations thereof; and 
   magnesium in an amount up to 90 wt-%.   
     
     
         2 . The alloy according to  claim 1 , wherein the amount of yttrium is no less than 4.5 wt-%. 
     
     
         3 . The alloy according to  claim 2 , wherein the amount of the rare earth element other than yttrium is no less than 4 wt-%. 
     
     
         4 . The alloy according to  claim 3 , wherein the amount of the rare earth element alloy component is no less than 9.5 wt-%. 
     
     
         5 . The alloy according to  claim 3 , wherein the rare earth element other than yttrium is a heavy rare earth element selected from gadolinium, dysprosium, and erbium. 
     
     
         6 . The alloy according to  claim 2 , wherein the amount of the rare earth element other than yttrium is no less than 5 wt-%. 
     
     
         7 . The alloy according to  claim 6 , wherein the rare earth element other than yttrium comprises a combination of two rare earth elements other than yttrium. 
     
     
         8 . The alloy according to  claim 7 , wherein the rare earth element other than yttrium comprises a heavy rare earth element and a light rare earth element, wherein the heavy rare earth element is selected from gadolinium, dysprosium, erbium, and combinations thereof, wherein the light rare earth element is selected from neodymium, lanthanum, and cerium, and combinations thereof. 
     
     
         9 . The alloy according to  claim 8 , wherein the amount of the heavy rare earth element is greater than the amount of the light rare earth element. 
     
     
         10 . The alloy according to  claim 1 , wherein the amount of yttrium is greater than or equal to the amount of the rare earth element other than yttrium. 
     
     
         11 . The alloy according to  claim 1 , further comprising at least one of zinc in an amount greater than 0.1 wt-% and zirconium in an amount greater than 0.3 wt-%. 
     
     
         12 . The alloy according to  claim 1 , comprising a substantial absence of an element selected from:
 scandium in an amount less than 1 wt-%,   calcium in an amount less than 0.05 wt-%,   indium in an amount less than 0.1 wt-%, and   combinations thereof.   
     
     
         13 . An alloy comprising:
 a rare earth element alloy component comprising:
 yttrium in an amount greater than 3 wt-%; and 
 a rare earth element other than yttrium in an amount greater than 1% selected from gadolinium, dysprosium, erbium, neodymium, lanthanum, cerium, and combinations thereof; and 
   magnesium in an amount up to 90 wt-%.   
     
     
         14 . The alloy according to  claim 13 , wherein an amount of the rare earth element alloy component is no less than 9.5 wt-%. 
     
     
         15 . The alloy according to  claim 14 , wherein the rare earth element other than yttrium comprises a combination of two rare earth elements other than yttrium. 
     
     
         16 . An alloy comprising:
 a rare earth element alloy component comprising:
 yttrium in an amount greater than 3 wt-%; and 
 a heavy rare earth element other than yttrium in an amount no less than 0.1 wt-% selected from gadolinium, dysprosium, erbium, and combinations thereof; and 
   magnesium in an amount up to 90 wt-%.   
     
     
         17 . The alloy according to  claim 16 , wherein an amount of the rare earth element alloy component is no less than 9.5 wt-%. 
     
     
         18 . An alloy comprising:
 a rare earth element alloy component in an amount no less than 10 wt-% comprising:
 yttrium in an amount greater than 2 wt-%; and 
 a rare earth element other than yttrium in an amount greater than 1 wt-% selected from gadolinium, dysprosium, erbium, neodymium, lanthanum, cerium, and combinations thereof; and 
   magnesium in an amount up to a balance of the alloy.   
     
     
         19 . The alloy according to  claim 18 , wherein an amount of the rare earth element alloy component is no less than 9.5 wt-%. 
     
     
         20 . The alloy according to  claim 18 , comprising a substantial absence of an element selected from:
 scandium in an amount less than 1 wt-%,   calcium in an amount less than 0.05 wt-%,   indium in an amount less than 0.1 wt-%, and   combinations thereof.