High strength, creep resistant zinc alloy

Abstract

Provided are high strength, creep resistant zinc alloys with superior mechanical and other properties.

1 . A zinc alloy comprising about 4% to about 8% Al and about 3% to about 9% Cu, optionally one or more additives, optionally one or more impurities, with the rest essentially Zinc, wt/wt. 
     
     
         2 . The zinc alloy of  claim 1 , wherein the alloy has about 5% to about 8% Al, wt/wt. 
     
     
         3 . The zinc alloy of  claim 1 , wherein the alloy has about 4% Al to about 5% Al, and about 3% to about 6% Cu, wt/wt. 
     
     
         4 . The zinc alloy of  claim 1 , wherein the alloy has about 7% to about 8% Al and about 5% to 9% Cu, wt/wt. 
     
     
         5 . The zinc alloy of  claim 1 , wherein the alloy has about 6% to about 7% Al, and about 5% to about 7% Cu, wt/wt. 
     
     
         6 . The zinc alloy of  claim 1 , wherein the alloy has about 6% to about 6.8% Al and about 6.5% to about 6% Cu, wt/wt. 
     
     
         7 . The zinc alloy of  claim 1 , wherein the alloy has about 6.4% to about 6.8% Al and about 5.2% to about 5.7% Cu, wt/wt. 
     
     
         8 . The zinc alloy of  claim 1 , wherein the alloy has about 6% to about 6.8% Al and about 5% to about 6% Cu, wt/wt. 
     
     
         9 . The zinc alloy of  claim 1 , wherein the alloy has about 6.6% aluminum by weight and about 5.5% copper by weight. 
     
     
         10 . The zinc alloy of  claim 1 , wherein Cu relative to Al is in a ratio of about 1 to about 0.74 Cu to Al. 
     
     
         11 . The zinc alloy of  claim 1 , wherein Cu relative to Al is in a ratio of about 1 to about 0.85 Cu to Al. 
     
     
         12 . The zinc alloy of  claim 1 , wherein the alloy has bout 3.9% to about 8.3% by weight Al and about 4.1% to about 6.5% by weight Cu. 
     
     
         13 . The zinc alloy of  claim 1 , wherein the alloy has about 5.3% to about 7.3% by weight Al and about 4.2% to about 6.5% by weight Cu. 
     
     
         14 . The zinc alloy of  claim 1 , wherein the alloy comprises one or more of additives selected from the group consisting of magnesium of about 0.025 to about 0.05 wt/wt, chromium in amounts up to 0.2% wt/wt, and titanium up to about 0.3% wt/wt, and combinations thereof. 
     
     
         15 . The zinc alloy of  claim 1 , wherein the alloy has one or more of incidental impurities. 
     
     
         16 . The zinc alloy of  claim 15 , wherein the impurities are selected from the group consisting of at least one of lead to a maximum of about 0.005%, cadmium to a maximum of about 0.004%, tin to a maximum of about 0.003%, iron to a maximum of about 0.1%, and combinations thereof. 
     
     
         17 . The zinc alloy of  claim 1 , wherein the alloy has a creep resistance of more than about 100 hours, at 140° C., 31 MPa, based on a testing run to completion (final rupture) with a cylindrical die cast sample. 
     
     
         18 . The zinc alloy of  claim 17 , wherein the alloy has a creep resistance of more than about 300 hours. 
     
     
         19 . The zinc alloy of  claim 1 , wherein the alloy has a hardness of about 63 to about 70, when measured with a 100K load with Rockwell B. 
     
     
         20 . The zinc alloy of  claim 1 , wherein the alloy has a yield strength at room temperature of about 345 to about 414 MPa. 
     
     
         21 . The zinc alloy of  claim 1 , wherein the alloy has an ultimate tensile strength at room temperature of about 345 to about 414 MPa. 
     
     
         22 . The zinc alloy of  claim 21 , wherein the alloy has an ultimate tensile strength of about 379 to about 414 MPa. 
     
     
         23 . The zinc alloy of  claim 1 , wherein the alloy has ultimate tensile strength at 212° F. of about 240 to about 280 MPa. 
     
     
         24 . The zinc alloy of  claim 23 , wherein the alloy has ultimate tensile strength at 212° F. of about 250 to about 270 MPa. 
     
     
         25 . The zinc alloy of  claim 1 , wherein the alloy has yield strength at 212° F. of about 150 MPa to about 170 MPa. 
     
     
         26 . The zinc alloy of  claim 1 , wherein the alloy has a primary phase that is Epsilon (Cu rich), surrounded by ternary eutectic matrix (Epsilon, Eta, Alpha). 
     
     
         27 . The zinc alloy of  claim 1 , wherein the alloy has a microstructure as depicted in top portion of  FIG. 7 . 
     
     
         28 . The zinc alloy of  claim 1 , wherein the alloy has a liquid temperature of about 711° F. to about 842° F. 
     
     
         29 . The zinc alloy of  claim 1 , wherein the alloy is in the form of a die cast, an ingot, or a gravity cast. 
     
     
         30 . A zinc alloy comprising about 4% to about 8% Al and about 3% to about 9% Cu, magnesium of about 0 to about 0.05 wt/wt, chromium of about 0 to about 0.2% wt/wt, titanium of about 0 to about 0.3% wt/wt, lead of about 0 to about 0.005%, cadmium of about 0 to about 0.004%, tin of about 0 to about 0.003%, iron of about 0 to about 0.1%, with the rest essentially Zinc, wt/wt. 
     
     
         31 . A process for preparing the zinc alloy of  claim 1  in solid form comprising combining zinc, cupper and aluminum with any optional additives to obtain a homogeneous liquid mixture, and cooling the mixture to solidify the mixture.