Dissolvable magnesium alloy

Abstract

A dissolvable magnesium alloy can be used for components of a downhole tool. The dissolvable magnesium alloy can be dissolved completely and controlled at a dissolving rate so as to be compatible with downhole operations, including hydraulic fracturing operations. The alloy includes nickel at 0.04-0.4% by weight and the balance of magnesium. The alloy is dissolvable in KCl at 2.1% by weight and 95 QC with a dissolving rate in a range of 10-100 mg/cm2/hr, yield strength in a range of 18-37 ksi, ultimate tensile strength in a range of 29-47 ksi, and elongation in a range of 8-40%.

1 . A dissolvable alloy for a component of a downhole tool, comprising:
 from 0.04 to 0.4 wt % nickel;   1.4 wt %-2.0 wt % copper;   3.1 wt %-15 wt % gadolinium;   4.0 wt %-15 wt % yttrium;   0.5 wt %-3.3 wt % aluminum; and   at least 83.5 wt % magnesium so as to be dissolvable in KCl at 2.1% by weight and 93° C. with a dissolving rate in a range of from 10 to 100 mg/cm 2 /hr, yield strength in a range of from 25 to about 37 ksi, ultimate tensile strength in a range of from 35 to 45 ksi, and elongation in a range of from 10 to 19%, wherein the dissolvable alloy does not have Zr.   
     
     
         2 . The dissolvable alloy of  claim 1  further comprising 0-20% lithium by weight, 3.1% gadolinium by weight, 4% yttrium by weight, 1.4% copper by weight. 
     
     
         3 . The dissolvable alloy of  claim 2 , further comprising up to 10 wt % total of other elements. which comprises one of manganese, neodymium, cerium, calcium, iron, bismuth, indium, or silver. 
     
     
         4 . (canceled) 
     
     
         5 . The dissolvable alloy of  claim 3 , wherein said copper is 1.4 wt %, said aluminum is 10.1 wt %, said zinc is 0.45 wt %, said nickel is 0.15 wt %, and said manganese is 0.16 wt %. 
     
     
         6 . The dissolvable alloy of  claim 2 , wherein said copper is 0.4 wt %, said nickel is 0.04 wt %, and said aluminum is 0.5 wt %. 
     
     
         7 . The dissolvable alloy of  claim 2 , wherein said gadolinium is 3.1 wt %, said copper is 1.4 wt %, said nickel is 0.04 wt %, and said aluminum is about 0.5 wt %. 
     
     
         8 . The dissolvable alloy of  claim 2 , wherein said gadolinium is 3.1 wt %, said copper is 0.4 wt %, said nickel is 0.04 wt %, and said aluminum is 0.5 wt %. 
     
     
         9 . The dissolvable alloy of  claim 2 , wherein said copper is 0.4 wt %, said nickel is 0.15 wt %, and said aluminum is 5.6 wt %. 
     
     
         10 . The dissolvable alloy of  claim 2 , wherein said copper is 1.2 wt %, said nickel is 0.4 wt %, and zinc is 6.1 wt %. 
     
     
         11 . The dissolvable alloy of  claim 2 , wherein said gadolinium is 1.56 wt %, said nickel is 0.04 wt %, and wherein said zinc is 3.88 wt %. 
     
     
         12 . The dissolvable alloy of  claim 2 , wherein said lithium is 11 wt %, said gadolinium is 1.0 wt %, said yttrium is 0.6 wt %, said nickel is 0.4 wt %, said copper is 0.2 wt %, and wherein said zinc is 3.3 wt %. 
     
     
         13 . An alloy, comprising:
 0-20% lithium by weight,   0-15% gadolinium by weight,   0-15% yttrium by weight,   0-2% copper by weight,   0-15% aluminum by weight,   0.04% to about 0.4% nickel by weight;   the balance of magnesium (Mg) and inevitable impurities, so as to be dissolvable in KCl at 2.1% by weight and about 93° C. with a dissolving rate in a range of from 10 to 100 mg/cm 2 /hr, yield strength in a range of from 25 to 37 ksi, ultimate tensile strength in a range of from 35 to 45 ksi, and elongation in a range of from 10 to 19%.   
     
     
         14 . The alloy of  claim 13 , further comprising up to 10% total of other elements. which comprises one of manganese, neodymium, cerium, calcium, iron, bismuth, indium, or silver. 
     
     
         15 . The alloy of  claim 13 , wherein the copper to nickel ratio is within the range of 50:1 to 0.1:1 wt %. 
     
     
         16 . The alloy of  claim 15 , wherein said range of aluminum is 7 to 12 wt %, particularly when the range of aluminum to copper is in the range of 3.5:1 to 60:1 wt %. 
     
     
         17 . The alloy of  claim 13 , wherein said range of zinc is 0.5 to 3 wt %, particularly when the range of copper to zinc is in the range of 0.07:1 to 4:1 wt %. 
     
     
         18 . An alloy, comprising:
 0.04% to about 0.4% nickel by weight;   0.2% to about 2% copper by weight; and   the balance of magnesium (Mg) and inevitable impurities, wherein the alloy yields strength in a range of from 25 to 37 ksi, ultimate tensile strength in a range of from 35 to ksi, and elongation in a range of from about 10 to about 19%.   
     
     
         19 . The alloy of  claim 18 , further comprising lithium by weight, 0-15% gadolinium by weight, 0-15% yttrium by weight, 0-15% aluminum by weight. 
     
     
         20 . The alloy of  claim 18 , further comprising up to 10 wt % total of other elements. which comprises one of manganese, neodymium, cerium, calcium, iron, bismuth, indium, or silver.