Disclosure of Invention
The invention aims to solve the problems of low strength, poor toughness and insufficient ductility of commercial aluminum alloy in an as-cast state in the prior art, and provides a scandium-containing high-toughness aluminum-silicon alloy.
The second purpose of the invention is to provide a preparation process of the scandium-containing high-strength and high-toughness aluminum-silicon alloy.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the scandium-containing high-strength and high-toughness aluminum-silicon alloy comprises the following components in percentage by weight:
sc 0.15-0.2%, Si: 9.5-11.5%, Mg: 0.1-0.35%, Mn: 0.08-0.3%, Zn: 0.01-0.2 percent of scandium-containing high-strength aluminum-silicon alloy, 0.2-1.0 percent of Co, and the balance of Al and inevitable impurities, wherein the scandium-containing high-strength aluminum-silicon alloy has a composition proportion relation satisfying the following formulas (1) and (2):
0.8≤({Mn}+{Zn})/{Mg}≤1.0……(1);
{Co}/{Mg}≧1.5……(2);
wherein { Mn }, { Zn }, { Mg } and { Co } respectively represent the weight percentages of Mn, Zn, Mg and Co in the scandium-containing high-strength and high-toughness aluminum-silicon alloy.
The alloying degree of the ultrahigh-strength aluminum alloy is relatively high, so that the alloy is extremely easy to generate element segregation in the solidification process, and the coarse eutectic structures are gathered at the crystal points due to the nonequilibrium crystallization effect generated when the alloy is rapidly cooled. Meanwhile, the rapid cooling of the alloy can generate strong internal stress in the matrix. Both the precipitation of non-equilibrium terms and the generation of internal stresses can cause a decrease in the workability of the material, affecting the properties of the final alloy article (strength, toughness and corrosion resistance)
According to the scandium-containing high-strength and high-toughness aluminum-silicon alloy, scandium, manganese, zinc and cobalt elements are added into the aluminum-silicon alloy, and the percentage contents of { Mn }, { Zn }, { Mg } and { Co } are strictly controlled, so that the effect of refining aluminum dendrites and eutectic silicon can be achieved, the strength and toughness of the aluminum-silicon alloy are remarkably improved, and meanwhile, the precipitation of unbalanced items of alloy elements is overcome through an effective heat treatment process. The alloy can generate natural aging effect within room temperature aging time through the component regulation and control of the material.
Wherein the content range epsilon (0.8-1.0) of ({ Mn } + { Zn })/{ Mg }, the inventor of the application finds that the total content of ({ Mn } + { Zn }) and the ratio corresponding to the { Mg } content have obvious influence on the comprehensive performance of the scandium-containing high-strength and high-toughness aluminum-silicon alloy. When the total content of { Mn } + { Zn }) is too low, the effect of solving the high strength and toughness cannot be achieved, but the { Mg } content is also correlated, and considering that the content of ({ Mn } + { Zn }) is influenced by the { Mg } content.
The addition of Co (cobalt) improves the strength better. Therefore, from the viewpoint of improving the alloy characteristics, the higher the amount of Co added, the better. However, since the solid solubility of Co in the aluminum matrix is relatively small, excessive addition is of no significance. If the content of Co is too small, it is difficult to effectively achieve the strength target of the present invention. Therefore, the content of Co must be controlled to 0.2 to 1.0%. And the dosage of the cobalt is also required to be related to the content of the { Mg }, and the content of the Co (cobalt) is influenced by the content of the { Mg }.
Preferably, the scandium-containing high-strength high-toughness aluminum-silicon alloy comprises the following components in percentage by weight:
sc 0.16-0.18%, Si: 10.5-11.0%, Mg: 0.15-0.30%, Mn: 0.1-0.20%, Zn: 0.05 to 0.10 percent of scandium-containing high-strength aluminum-silicon alloy, 0.4 to 0.6 percent of Co, and the balance of Al and inevitable impurities, wherein the scandium-containing high-strength aluminum-silicon alloy has a composition proportion relation satisfying the following formulas (1) and (2):
({Mn}+{Zn})/{Mg}=1……(1);
{Co}/{Mg}≧2.0……(2);
wherein { Mn }, { Zn }, { Mg } and { Co } respectively represent the weight percentages of Mn, Zn, Mg and Co in the scandium-containing high-strength and high-toughness aluminum-silicon alloy.
Preferably, the scandium-containing high-strength high-toughness aluminum-silicon alloy comprises the following components in percentage by weight:
sc is 0.18%, Si: 10.0%, Mg: 0.2%, Mn: 0.195%, Zn: 0.05%, Co 0.5%, and the balance Al and unavoidable impurities.
Preferably, any one or more elements of Fe, Cr, Zr and Ti are further included, and the total amount thereof is 1.0wt% or less.
Preferably, the total amount of any one or more of Fe, Cr, Zr and Ti is 0.4 to 0.6 wt%.
The other elements may contain Fe, Cr, Zr, and Ti, as the case may be. Fe, Cr, Zr and Ti have the functions of refining the cast crystal grains and slowing down element segregation; when one or more of Fe, Cr, Zr and Ti elements are contained, the total content is preferably 0.01 wt% or more in order to sufficiently exhibit the above-mentioned various effects. However, when the content of each element is too large, the hot workability or cold workability is likely to be lowered, and the raw material cost is likely to be increased. Therefore, the total content of these elements is preferably controlled to 1.0wt% or less.
Preferably, it has an average grain diameter of 8 to 12 μm. As a result of the detailed investigation by the present inventors, if the final average crystal grain size is 8 μm or more and 12 μm or less, the above-mentioned desired objects of the present invention for toughness and strength can be satisfied at the same time.
A preparation process of scandium-containing high-strength high-toughness aluminum-silicon alloy comprises the following steps:
step S1 smelting: putting a pure aluminum ingot into a melter, heating to 750 ℃ with the temperature increased to 730 plus materials, spreading a layer of covering agent after the aluminum block is half-melted, after the aluminum liquid is completely melted, heating to 820 ℃ with the temperature increased to 800 plus materials, sequentially putting aluminum silicon and aluminum manganese in proportion during the heating process, after the temperature is increased to 820 ℃ with the temperature increased to 800 plus materials, sequentially adding aluminum scandium and aluminum cobalt in proportion, uniformly stirring and preserving the temperature for 30-45min after melting, cooling to 720 ℃ with the temperature increased to 700 plus materials, adding pure magnesium ingot and zinc ingot, uniformly stirring and refining, degassing by using a rotary blowing high-purity argon method after refining for 15-30min, deslagging after degassing time is 15-30min, preserving the temperature and standing for 15-20min with the temperature increased to 680 plus materials, detecting chemical components, and finishing casting after the component contents reach standards to obtain mixed aluminum liquid;
step S2 die casting: carrying out standard extrusion casting on the smelted mixed aluminum liquid, controlling the temperature of the aluminum liquid at 660-690 ℃, and controlling the temperature of a mold at 200-220 ℃;
step S3 heat treatment: the casting is subjected to solution treatment at 440-450 ℃ for 4-6h, and then artificial aging at 150-160 ℃ for 4-12h or natural aging for 12-24h is selected.
Preferably, in step S1, the heating rate of the heating process is 1.5-2.0 deg.C/min.
Preferably, the heat treatment in the step S3 adopts artificial aging treatment, and the treatment time is 6-8 h.
Preferably, the heat treatment in the step S3 adopts natural aging treatment, and the treatment time is 16-20 h.
In the embodiment of the invention, the performances after different aging treatment modes are as follows: after the artificial aging treatment, the tensile strength is 340-360 Mpa, the yield strength is more than or equal to 220MP, and the elongation is 4-5%; after natural aging treatment, the tensile strength is 320-350 MPa, the yield strength is more than or equal to 180MPa, and the elongation is 6-8%. After artificial aging, the strength performance of the material is improved to some extent compared with natural aging, but the elongation is reduced to some extent.
The invention has the beneficial effects that: according to the scandium-containing high-strength and high-toughness aluminum-silicon alloy, scandium, manganese, zinc and cobalt elements are added into the aluminum-silicon alloy, and the percentage contents of { Mn }, { Zn }, { Mg } and { Co } are strictly controlled, so that the effect of refining aluminum dendrites and eutectic silicon can be achieved, the strength and toughness of the aluminum-silicon alloy are remarkably improved, and meanwhile, the precipitation of unbalanced items of alloy elements is overcome through an effective heat treatment process. The alloy can generate natural aging effect within room temperature aging time through the component regulation and control of the material.
Detailed Description
The technical solution of the present invention will be further specifically described below by way of specific examples.
Example 1:
the scandium-containing high-strength and high-toughness aluminum-silicon alloy comprises the following components in percentage by weight: sc is 0.15%, Si: 9.5%, Mg: 0.1%, Mn: 0.08%, Zn: 0.01 percent of scandium, 0.2 percent of Co, and the balance of Al and inevitable impurities, and the scandium-containing high-strength and high-toughness aluminum-silicon alloy has the composition proportion relation satisfying the following formulas (1) and (2):
0.8 ≦ ({ Mn } + { Zn })/{ Mg } ≦ 1.0 … … (1), specifically ({ Mn } + { Zn })/{ Mg } ═ 0.9;
{ Co }/{ Mg } > 1.5 … … (2); specifically, { Co }/{ Mg } ═ 2;
wherein { Mn }, { Zn }, { Mg } and { Co } respectively represent the weight percentages of Mn, Zn, Mg and Co in the scandium-containing high-strength and high-toughness aluminum-silicon alloy.
The high-toughness scandium-containing aluminum-silicon alloy of example 1 had an average crystal grain diameter of 8 to 12 μm. The preparation process comprises the following steps:
step S1 smelting: putting a pure aluminum ingot into a melter, heating to 740-;
step S2 die casting: carrying out standard extrusion casting on the smelted mixed aluminum liquid, controlling the temperature of the aluminum liquid at 660-670 ℃, and controlling the temperature of a die at 200-210 ℃;
step S3 heat treatment: the casting is subjected to solution treatment for 6h at 440 ℃, and then artificial aging for 12h at 150 ℃ is selected. In step S1, the heating rates in the heating process are all 1.5 ℃/min.
The scandium-containing high-toughness Al-Si alloy in example 1 has a tensile strength of 342MPa, a yield strength of 232MP and an elongation of 4.2%
Example 2:
the scandium-containing high-strength and high-toughness aluminum-silicon alloy comprises the following components in percentage by weight:
sc is 0.2%, and Si: 11.5%, Mg: 0.35%, Mn: 0.3%, Zn: 0.05 percent, Co 1.0 percent and the balance of Al and inevitable impurities, and the scandium-containing high-strength high-toughness aluminum-silicon alloy has the composition proportion relation satisfying the following formulas (1) and (2):
less than or equal to 0.8 ({ Mn } + { Zn })/{ Mg } < 1.0 … … (1); specifically ({ Mn } + { Zn })/{ Mg } ═ 1.0;
{ Co }/{ Mg } > 1.5 … … (2); specifically, { Co }/{ Mg } -, 2.858;
wherein { Mn }, { Zn }, { Mg } and { Co } respectively represent the weight percentages of Mn, Zn, Mg and Co in the scandium-containing high-strength and high-toughness aluminum-silicon alloy.
The scandium-containing high-toughness aluminum-silicon alloy of example 2 had an average crystal grain diameter of 8 to 12 μm. The preparation process comprises the following steps:
step S1 smelting: putting a pure aluminum ingot into a melter, heating to 740-;
step S2 die casting: carrying out standard extrusion casting on the smelted mixed aluminum liquid, controlling the temperature of the aluminum liquid at 680-690 ℃ and controlling the temperature of a die at 210-220 ℃;
step S3 heat treatment: the casting is subjected to solution treatment for 4h at 450 ℃, and then artificial aging for 4h at 160 ℃ is selected.
The scandium-containing high-strength and high-toughness Al-Si alloy in example 2 has a tensile strength of 352MPa, a yield strength of 236MP and an elongation of 4.49%
Example 3:
the scandium-containing high-strength and high-toughness aluminum-silicon alloy comprises the following components in percentage by weight:
the scandium-containing high-strength high-toughness aluminum-silicon alloy comprises the following components in percentage by weight:
sc is 0.16%, Si: 10.5%, Mg: 0.15%, Mn: 0.1%, Zn: 0.05 percent of scandium, 0.4 percent of Co and the balance of Al and inevitable impurities, and the scandium-containing high-strength and high-toughness aluminum-silicon alloy has the composition proportion relation satisfying the following formulas (1) and (2):
({Mn}+{Zn})/{Mg}=1……(1);
{Co}/{Mg}=2.667……(2);
wherein { Mn }, { Zn }, { Mg } and { Co } respectively represent the weight percentages of Mn, Zn, Mg and Co in the scandium-containing high-strength and high-toughness aluminum-silicon alloy.
Example 3 had an average grain diameter of 8-12 μm. The preparation process comprises the following steps: step S1 smelting: putting a pure aluminum ingot into a melter, heating to 740-;
step S2 die casting: carrying out standard extrusion casting on the smelted mixed aluminum liquid, controlling the temperature of the aluminum liquid at 660 ℃ and controlling the temperature of a mould at 220 ℃;
step S3 heat treatment: the casting is subjected to solution treatment for 4h at 450 ℃, and natural aging is selected for 12 h.
The scandium-containing high-strength and high-toughness Al-Si alloy in example 3 has a tensile strength of 328MPa, a yield strength of 186MP and an elongation of 6.9%
Example 4:
the scandium-containing high-strength and high-toughness aluminum-silicon alloy comprises the following components in percentage by weight:
sc is 0.18%, Si: 11.0%, Mg: 0.20%, Mn: 0.1%, Zn: 0.10 percent of scandium, 0.6 percent of Co0.6 percent, and the balance of Al and inevitable impurities, wherein the scandium-containing high-strength and high-toughness aluminum-silicon alloy has a composition proportion relation satisfying the following formulas (1) and (2):
({Mn}+{Zn})/{Mg}=1……(1);
{Co}/{Mg}=3.0……(2);
wherein { Mn }, { Zn }, { Mg } and { Co } respectively represent the weight percentages of Mn, Zn, Mg and Co in the scandium-containing high-strength and high-toughness aluminum-silicon alloy.
The scandium-containing high-toughness aluminum-silicon alloy of example 4 had an average crystal grain diameter of 8 to 12 μm. The preparation process comprises the following steps:
step S1 smelting: putting a pure aluminum ingot into a melter, heating to 745 ℃ and 750 ℃, spraying a layer of covering agent after the aluminum block is semi-molten, after the aluminum liquid is completely molten, heating to 810 ℃ and 820 ℃, sequentially adding aluminum silicon and aluminum manganese according to the proportion in the heating process, when the temperature is increased to 810 ℃ and 820 ℃, sequentially adding aluminum scandium and aluminum cobalt according to the proportion, uniformly stirring and preserving heat for 40-45min after melting, cooling to 710 ℃ and 720 ℃, adding a pure magnesium ingot and a zinc ingot, uniformly stirring and refining, degassing by using a rotary blowing high-purity argon method after refining for 25-30min, deslagging after degassing for 25-30min, preserving heat at 680 ℃ and 690 ℃ for 15-20min, carrying out chemical component detection, and finishing casting after the component content reaches the standard to obtain mixed aluminum liquid;
step S2 die casting: carrying out standard extrusion casting on the smelted mixed aluminum liquid, controlling the temperature of the aluminum liquid at 680-690 ℃ and controlling the temperature of a die at 210-220 ℃;
step S3 heat treatment: the casting is subjected to solution treatment for 4 hours at 450 ℃, and then natural aging is selected for 24 hours.
The scandium-containing high-strength and high-toughness Al-Si alloy in example 4 has a tensile strength of 332MPa, a yield strength of 196MP and an elongation of 7.29%
Example 5:
the scandium-containing high-strength and high-toughness aluminum-silicon alloy comprises the following components in percentage by weight: sc is 0.18%, Si: 10.0%, Mg: 0.2%, Mn: 0.195%, Zn: 0.05%, Co 0.5%, and the balance Al and unavoidable impurities.
The preparation process is the same as in example 1.
The scandium-containing high-strength aluminum-silicon alloy of example 5 had a tensile strength of 352MPa, a yield strength of 232MP, and an elongation of 4.6%
Example 6:
basically, the method is the same as the method in example 1, except that the method further comprises the following steps: fe. The total amount of Cr was 0.4 wt%, 0.2% each.
The scandium-containing high-strength and high-toughness Al-Si alloy in example 6 has a tensile strength of 353MPa, a yield strength of 235MP and an elongation of 4.35%
Example 7
Basically, the method is the same as the method in example 1, except that the method further comprises the following steps: zr and Ti, the total amount being 0.6wt%, 0.3% each.
The scandium-containing high-strength and high-toughness Al-Si alloy in example 7 has a tensile strength of 355MPa, a yield strength of 234MP and an elongation of 4.3%
Example 8
Basically, the method is the same as the method in example 1, except that the method further comprises the following steps: fe. Cr, Zr and Ti, the total amount being 1.0wt%
The scandium-containing high-strength and high-toughness Al-Si alloy in example 8 has a tensile strength of 360MPa, a yield strength of 242MP and an elongation of 4.6%
The alloying degree of the ultrahigh-strength aluminum alloy is relatively high, so that the alloy is extremely easy to generate element segregation in the solidification process, and the coarse eutectic structures are gathered at the crystal points due to the nonequilibrium crystallization effect generated when the alloy is rapidly cooled. Meanwhile, the rapid cooling of the alloy can generate strong internal stress in the matrix. Both the precipitation of non-equilibrium terms and the generation of internal stresses can cause a decrease in the workability of the material, affecting the properties of the final alloy article (strength, toughness and corrosion resistance)
According to the scandium-containing high-strength and high-toughness aluminum-silicon alloy, scandium, manganese, zinc and cobalt elements are added into the aluminum-silicon alloy, and the percentage contents of { Mn }, { Zn }, { Mg } and { Co } are strictly controlled, so that the effect of refining aluminum dendrites and eutectic silicon can be achieved, the strength and toughness of the aluminum-silicon alloy are remarkably improved, and meanwhile, the precipitation of unbalanced items of alloy elements is overcome through an effective heat treatment process. The alloy can generate natural aging effect within room temperature aging time through the component regulation and control of the material.
Wherein the content range epsilon (0.8-1.0) of ({ Mn } + { Zn })/{ Mg }, the inventor of the application finds that the total content of ({ Mn } + { Zn }) and the ratio corresponding to the { Mg } content have obvious influence on the comprehensive performance of the scandium-containing high-strength and high-toughness aluminum-silicon alloy. When the total content of { Mn } + { Zn }) is too low, the effect of solving the high strength and toughness cannot be achieved, but the { Mg } content is also correlated, and considering that the content of ({ Mn } + { Zn }) is influenced by the { Mg } content.
The addition of Co (cobalt) improves the strength better. Therefore, from the viewpoint of improving the alloy characteristics, the higher the amount of Co added, the better. However, since the solid solubility of Co in the aluminum matrix is relatively small, excessive addition is of no significance. If the content of Co is too small, it is difficult to effectively achieve the strength target of the present invention. Therefore, the content of Co must be controlled to 0.2 to 1.0%. And the dosage of the cobalt is also required to be related to the content of the { Mg }, and the content of the Co (cobalt) is influenced by the content of the { Mg }.
The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.