High-strength and high-toughness high-magnesium aluminum alloy and preparation method thereof

Abstract

The present invention relates to a high-strength and high-toughness high-magnesium aluminum alloy and a preparation method thereof. The high-strength and high-toughness high-magnesium aluminum alloy provided by the present invention comprises the following components in percentage by mass: 5.54-6.80% of Mg, 0.50-0.60% of Mn, 0.12-0.16% of Zr, 0.30-0.36% of Er, less than or equal to 0.3% of Si, less than or equal to 0.2% of Fe and the balance of Al. In the present invention, the content of each element is strictly controlled, after a proper amount of Zr and Er rare earth elements in mass percent are added into the aluminum alloy, the mass percent of Mg element in the aluminum alloy is further controlled, so that the Mg element can interact with the rare earth elements efficiently, and the strength and toughness matching of the aluminum alloy with an Al—Mg—Mn—Zr—Er multi-element system can be improved.

What is claimed is: 
     
         1 . A high-strength and high-toughness high-magnesium aluminum alloy, comprising the following components in percentage by mass: 5.54˜6.80% of Mg, 0.50˜0.60% of Mn, 0.12˜0.16% of Zr, 0.30˜0.36% of Er, less than or equal to 0.3% of Si, less than or equal to 0.2% of Fe and the balance of Al. 
     
     
         2 . The high-strength and high-toughness high-magnesium aluminum alloy according to  claim 1 , comprising the following components in percentage by mass: 5.70% of Mg, 0.56% of Mn, 0.14% of Zr, 0.30% of Er, 0.23% of Si, 0.16% of Fe and the balance of Al. 
     
     
         3 . A method for preparing the high-strength and high-toughness high-magnesium aluminum alloy according to  claim 1 , comprising the steps of:
 Smelting an aluminum source, a magnesium source, a manganese source, a zirconium source and an erbium source to obtain a smelted aluminum alloy liquid;   Refining the smelted aluminum alloy liquid to obtain refined aluminum alloy liquid;   Casting the refined aluminum alloy liquid to obtain an as-cast aluminum alloy;   Carrying out homogenizing annealing treatment on the as-cast aluminum alloy to obtain the high-strength and high-toughness high-magnesium aluminum alloy;   The homogenizing annealing treatment comprises the steps of: preserving heat at 310-330° C. for 20-22 h, and then preserving heat at 440-460° C. for 18-20 h.   
     
     
         4 . A method for preparing the high-strength and high-toughness high-magnesium aluminum alloy according to  claim 2 , comprising the steps of:
 Smelting an aluminum source, a magnesium source, a manganese source, a zirconium source and an erbium source to obtain a smelted aluminum alloy liquid;   Refining the smelted aluminum alloy liquid to obtain refined aluminum alloy liquid;   Casting the refined aluminum alloy liquid to obtain an as-cast aluminum alloy;   Carrying out homogenizing annealing treatment on the as-cast aluminum alloy to obtain the high-strength and high-toughness high-magnesium aluminum alloy;   The homogenizing annealing treatment comprises the steps of: preserving heat at 310-330° C. for 20-22 h, and then preserving heat at 440-460° C. for 18-20 h.   
     
     
         5 . The preparation method according to  claim 3 , wherein the smelting comprises the steps of:
 Adding the aluminum source and the manganese source into a first covering agent at a first temperature for a first heat preservation to obtain an initial aluminum alloy liquid;   Adding the initial aluminum alloy liquid, the zirconium source and the erbium source into a second covering agent at a second temperature for a second heat preservation to obtain a transitional aluminum alloy liquid;   Adding the transitional aluminum alloy liquid and the magnesium source into a third covering agent at a third temperature for a third heat preservation to obtain the smelted aluminum alloy liquid.   
     
     
         6 . The preparation method according to  claim 4 , wherein the smelting comprises the steps of:
 Adding the aluminum source and the manganese source into a first covering agent at a first temperature for a first heat preservation to obtain an initial aluminum alloy liquid;   Adding the initial aluminum alloy liquid, the zirconium source and the erbium source into a second covering agent at a second temperature for a second heat preservation to obtain a transitional aluminum alloy liquid;   Adding the transitional aluminum alloy liquid and the magnesium source into a third covering agent at a third temperature for a third heat preservation to obtain the smelted aluminum alloy liquid.   
     
     
         7 . The preparation method according to  claim 3 , wherein the refining comprises the step of:
 Adding the smelted aluminum alloy liquid into a refining agent at a fourth temperature for a fourth heat preservation to obtain the refined aluminum alloy liquid.   
     
     
         8 . The preparation method according to  claim 4 , wherein the refining comprises the step of:
 Adding the smelted aluminum alloy liquid into a refining agent at a fourth temperature for a fourth heat preservation to obtain the refined aluminum alloy liquid.   
     
     
         9 . The preparation method according to  claim 3 , wherein the casting comprises the step of:
 Pouring the refined aluminum alloy liquid after a fifth heat preservation at a fifth temperature to obtain the as-cast aluminum alloy.   
     
     
         10 . The preparation method according to  claim 4 , wherein the casting comprises the step of:
 Pouring the refined aluminum alloy liquid after a fifth heat preservation at a fifth temperature to obtain the as-cast aluminum alloy.   
     
     
         11 . The preparation method according to  claim 5 , wherein, the first temperature is 720˜760° C., the first heat preservation time is 15˜20 min; the second temperature is 760˜770° C., the second heat preservation time is 30˜35 min; the third temperature is 700˜710° C., the third heat preservation time is 25˜35 min; the fourth temperature is 760˜770° C., the fourth heat preservation time is 5˜10 min; the fifth temperature is 710˜720° C., the fifth heat preservation time is 20˜25 min. 
     
     
         12 . The preparation method according to  claim 6 , wherein, the first temperature is 720˜760° C., the first heat preservation time is 15˜20 min; the second temperature is 760˜770° C., the second heat preservation time is 30˜35 min; the third temperature is 700˜710° C., the third heat preservation time is 25˜35 min; the fourth temperature is 760˜770° C., the fourth heat preservation time is 5˜10 min; the fifth temperature is 710˜720° C., the fifth heat preservation time is 20˜25 min. 
     
     
         13 . The preparation method according to  claim 7 , wherein, the first temperature is 720˜760° C., the first heat preservation time is 15˜20 min; the second temperature is 760˜770° C., the second heat preservation time is 30˜35 min; the third temperature is 700˜710° C., the third heat preservation time is 25˜35 min; the fourth temperature is 760˜770° C., the fourth heat preservation time is 5˜10 min; the fifth temperature is 710˜720° C., the fifth heat preservation time is 20˜25 min. 
     
     
         14 . The preparation method according to  claim 8 , wherein, the first temperature is 720˜760° C., the first heat preservation time is 15˜20 min; the second temperature is 760˜770° C., the second heat preservation time is 30˜35 min; the third temperature is 700˜710° C., the third heat preservation time is 25˜35 min; the fourth temperature is 760˜770° C., the fourth heat preservation time is 5˜10 min; the fifth temperature is 710˜720° C., the fifth heat preservation time is 20˜25 min. 
     
     
         15 . The preparation method according to  claim 9 , wherein, the first temperature is 720˜760° C., the first heat preservation time is 15˜20 min; the second temperature is 760˜770° C., the second heat preservation time is 30˜35 min; the third temperature is 700˜710° C., the third heat preservation time is 25˜35 min; the fourth temperature is 760˜770° C., the fourth heat preservation time is 5˜10 min; the fifth temperature is 710˜720° C., the fifth heat preservation time is 20˜25 min. 
     
     
         16 . The preparation method according to  claim 10 , wherein, the first temperature is 720˜760° C., the first heat preservation time is 15˜20 min; the second temperature is 760˜770° C., the second heat preservation time is 30˜35 min; the third temperature is 700˜710° C., the third heat preservation time is 25˜35 min; the fourth temperature is 760˜770° C., the fourth heat preservation time is 5˜10 min; the fifth temperature is 710˜720° C., the fifth heat preservation time is 20˜25 min. 
     
     
         17 . The preparation method according to  claim 5 , wherein the first covering agent, the second covering agent and the third covering agent are independently a mixture of CaF 2 , MgCl 2  and MgF 2  or a mixture of CaF 2 , MgCl 2  and CaCl 2 ; the adding amounts of the first covering agent, the second covering agent and the third covering agent are independently 0.3˜0.4% of the aluminum source by mass. 
     
     
         18 . The preparation method according to  claim 7 , wherein, the refining agent is C 2 Cl 6 , the adding amount of the refining agent is 0.3˜0.4% of the aluminum source by mass. 
     
     
         19 . The preparation method according to  claim 3 , wherein, the casting mold is used after being coated with paint, and the paint is ZnO, Na 2 SiO 3  and H 2 O at a mass ratio of 2:1:7. 
     
     
         20 . The preparation method according to  claim 9 , wherein, the casting mold is used after being coated with paint, and the paint is ZnO, Na 2 SiO 3  and H 2 O at a mass ratio of 2:1:7.