Medium-strength high-conductivity die-casting aluminum alloy and preparation method

Abstract

The invention provides a medium-strength high-conductivity die-casting aluminum alloy and a preparation method, and belongs to the technical field of high-pressure die-casting aluminum alloys. Wherein the aluminum alloy comprises the following components in percentage by weight: 1.0 to 4.0 percent of Fe, 0.05 to 0.85 percent of Ni, 0.1 to 0.78 percent of La and Ce, at most 0.05 percent of single impurity element, and the balance of Al. The aluminum alloy adopts specific Fe, Ni, La and Ce elements in percentage by weight, and Mn, Cr, V and Ti elements are strictly controlled, so that the tensile strength reaches 150-180 MPa, the yield strength reaches 70-90 MPa, the ductility reaches 15-20% and the conductivity reaches 50-59% IACS in an as-cast state, and the aluminum alloy has excellent conductivity and far exceeds the strength of pure aluminum; the aluminum alloy material provided by the invention is relatively low in Ni content, so that the material price is greatly reduced, and large-scale application of a high-conductivity material is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of high-pressure die-casting aluminum alloys, and in particular relates to a medium-strength and high-conductivity die-casting aluminum alloy and a preparation method thereof. Background Art

[0002] Die-cast aluminum alloys are widely used in the fields of automobiles, aviation, 3C electronics, electric power and electrical engineering due to their simple and efficient molding method and low post-processing. With the development of the industry, parts such as cast aluminum rotors and power fittings have put forward requirements for aluminum and aluminum alloys with high electrical conductivity and thermal conductivity, medium strength and high castability. Pure aluminum has excellent electrical conductivity, with an electrical conductivity of about 60% IACS, but its strength is relatively low and cannot be directly applied industrially. Traditional die-cast aluminum alloys (A356, A380, ADC12, AlSi10MnMg) contain a large amount of Si, but the high Si content makes the eutectic silicon content in the alloy still very high, which hinders electronic conduction. These alloy elements will greatly reduce the electrical conductivity of the material. Therefore, it is difficult for Al-Si alloys to obtain very high electrical conductivity in the cast state.

[0003] At present, high-conductivity die-cast aluminum alloys include Al-Ni, Al-Fe, and Al-Re, among which Al-Ni is the most widely used. The eutectic point of Al-Ni alloy is about 5wt.%, the limiting solid solubility in aluminum is low (about 0.05wt.%), and Al-Ni alloy has excellent electrical conductivity, so Al-Ni alloy is regarded as an important choice for new high thermal conductivity aluminum alloy. At present, a lot of research work on Al-Ni alloys has been carried out at home and abroad. Among them, Al-5.3Ni die-cast aluminum alloy, while ensuring good casting performance, the electrical conductivity can be as high as 50% IACS, which confirms the development potential of Al-Ni alloy in the field of high thermal conductivity die-cast aluminum alloy.

[0004] However, the price of Ni is high, about 7 times that of aluminum, which leads to the high price of Al-Ni alloy. Therefore, it is urgent to develop a cheap aluminum alloy material with similar conductivity to Al-Ni, which is very important for promoting the large-scale application of high-conductivity materials. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a medium-strength and high-conductivity voltage-cast aluminum alloy and a preparation method, so that the aluminum alloy has a tensile strength of 150-180 MPa, a yield strength of 70-90 MPa, an elongation of 15-20%, and an electrical conductivity of 50-59% IACS in the cast state.

[0006] In order to achieve the above advantages, in a first aspect, the present invention discloses a medium-strength and high-conductivity voltage-casting aluminum alloy, the components and weight percentages of the aluminum alloy are:

[0007] 1.0-4.0 wt% Fe, 0.05-0.85 wt% Ni, 0.1-0.78 wt% La and Ce, a single impurity element of up to 0.05 wt%, and the remainder Al.

[0008] As a further improvement of the present invention, the impurity elements include Mn, Cr, V, and Ti.

[0009] As a further improvement of the present invention, the Ti element is at most 0.02 wt%.

[0010] As a further improvement of the present invention, the weight ratio of La to Ce is 2:3.

[0011] As a further improvement of the present invention, the aluminum alloy has a tensile strength of 150-180 MPa, a yield strength of 70-90 MPa, an elongation of 15-20%, and an electrical conductivity of 50-59% IACS in the cast state.

[0012] In a second aspect, the present invention discloses a method for preparing the medium-strength and high-conductivity voltage cast aluminum alloy according to the first aspect of the present invention, comprising the following steps:

[0013] Step 1: gradually increase the temperature in the furnace according to the mass percentage of the aluminum alloy, bake out the water vapor in the furnace, and during the heating process, put the A00 weighed according to the proportion on the side of the furnace for baking and then put it into the furnace to heat and melt;

[0014] Step 2: After A00 is dissolved, place the master alloy on the side of the furnace for baking and then put it into the furnace, stir it several times to fully dissolve it, and let it stand;

[0015] Step 3: Use a degasser to press the aluminum alloy sodium-free refining agent into the refining machine, pass 99.999% argon gas, degas, then remove the slag and let it stand;

[0016] Step 4: Detect whether the aluminum alloy composition reaches the preset mass percentage of the aluminum alloy. If so, proceed to step 5. If not, add elements that do not reach the preset mass percentage so that the elements that do not reach the preset mass percentage reach the preset mass percentage.

[0017] Step 5: Detect the gas content, and when the density equivalent is ≤0.2%, proceed to step 6, otherwise continue the refining and degassing operation in step 3;

[0018] Step 6: Perform high pressure die casting through high pressure die casting equipment.

[0019] As a further improvement of the present invention, in step 1, the furnace side baking time of A00 is 30 minutes, the aluminum liquid temperature is set to 720°C, and the furnace temperature is set to 780°C.

[0020] As a further improvement of the present invention, in step 2, the furnace-side baking time of the intermediate alloy is 30 minutes, the intermediate alloy is AlFe20, AlNi20, AlRe20, and the standing time is 30 minutes.

[0021] As a further improvement of the present invention, in step 3, the refining agent ratio is 0.1% to 0.2%, and the degassing time is 15 minutes.

[0022] As a further improvement of the present invention, in step 6, the high-pressure die-casting equipment includes a vacuum system, an oil circulation mold temperature controller, and a barrel heating device.

[0023] As a further improvement of the present invention, in step 6, the process parameters of high pressure die casting are: mold cavity vacuum ≤50Mbar, injection speed is 2.5±0.5m / s, mold temperature is 130±10℃, and aluminum alloy liquid temperature is 700±10℃.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] First, by strictly controlling the contents of elements such as Mn, Cr, V, and Ti, the aluminum alloy material of the present invention has excellent electrical conductivity;

[0026] Second, the aluminum alloy material provided by the present invention adds appropriate amounts of Ce and La, which improves the cast structure of the alloy, refines the grains, increases the strength of the material, and increases the electrical conductivity of the alloy;

[0027] Thirdly, the aluminum alloy material provided by the present invention has a tensile strength of 150-180 MPa, a yield strength of 70-90 MPa, an elongation of 15-20%, and an electrical conductivity of 50-59% IACS in the cast state, and has excellent electrical conductivity, while far exceeding the strength of pure aluminum;

[0028] Fourthly, the aluminum alloy material provided by the present invention has a low Ni content, which greatly reduces the material price and helps promote the large-scale application of high-conductivity materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The 200-fold metallographic structure diagram of the medium-strength and high-conductivity voltage-cast aluminum alloy material disclosed in Example 6 of the present invention is shown;

[0030] Figure 2 A 500-fold metallographic structure diagram of the medium-strength and high-conductivity voltage-cast aluminum alloy material disclosed in Example 6 of the present invention is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the present invention will combine the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments, wherein step 1, step 2... in the embodiments described in the present invention do not limit the only execution steps of the present invention; the basic principles of the present invention defined in the description of the present invention can be applied to other implementation schemes, variant schemes, improved schemes, equivalent schemes and other technical schemes that do not deviate from the spirit and scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] The principle of the present invention is that the present invention is an Al-Fe-Ni-Re alloy, the Fe element has low cost, and can generate strengthening phases such as Al3Fe and Al6Fe with aluminum elements, while improving strength, the conductivity is only slightly reduced. The eutectic point of the Al-Fe alloy is 1.8% (mass fraction), and low alloying can achieve eutectic structure, achieve good casting performance, improve die-casting demoulding performance, and reduce corrosion to mold steel. Adding a small amount of Ni element, Ni will combine with Fe to form Al9NiFe, which is dispersed at the grain boundary, and can reduce the influence of Fe on conductivity. Ce and La elements have similar effects on the performance and microstructure of the alloy. Adding appropriate amounts of Ce and La to the aluminum alloy conductor material can improve the cast structure of the alloy, refine the grains to a certain extent, and improve the strength of the material. In addition, Ce and La can also form intermetallic compounds with Si, the main impurity element in industrial pure aluminum, reduce the concentration of solid solution atoms in the aluminum matrix, and thus improve the conductivity of the alloy.

[0033] In a first aspect, an embodiment of the present invention discloses a medium-strength and high-conductivity voltage-cast aluminum alloy, wherein the components and weight percentages of the aluminum alloy are:

[0034] 1.0-4.0 wt% Fe, 0.05-1.0 wt% Ni, 0.1-1.0 wt% La and Ce, a single impurity element of up to 0.05 wt%, and the rest is Al.

[0035] In a preferred embodiment, the components and weight percentages of the aluminum alloy are:

[0036] 1.0-4.0 wt% Fe, 0.05-0.85 wt% Ni, 0.1-0.78 wt% La and Ce, a single impurity element of up to 0.05 wt%, and the remainder Al.

[0037] In a preferred embodiment, the impurity elements include Mn, Cr, V, and Ti.

[0038] In a preferred embodiment, the Ti element is at most 0.02 wt%.

[0039] In a preferred embodiment, the weight ratio of La to Ce is 2:3.

[0040] It should be noted that in the embodiment of the present invention, the weight ratio of La to Ce is set to 2:3, which is only a preferred implementation, and other ratios may also be used. Any technical solution of 0.1 to 1.0 weight % of La and Ce in the present invention belongs to the protection scope of the present invention.

[0041] In a preferred embodiment, the aluminum alloy has a tensile strength of 150-180 MPa, a yield strength of 70-90 MPa, an elongation of 15-20%, and an electrical conductivity of 50-59% IACS in the cast state.

[0042] It should be noted that any numerical value within the weight percentage range of the aluminum alloy component belongs to the protection scope of the present invention. For example, the weight percentage of Fe can be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, and 4.0. Illustratively, the weight % of Ni may be 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, 0.6 1.0, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.0.Illustratively, the weight % of La and Ce may be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.53 , 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.82, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.0.

[0043] In a second aspect, an embodiment of the present invention discloses a method for preparing the medium-strength and high-conductivity voltage cast aluminum alloy according to the first aspect of the present invention, comprising the following steps:

[0044] Step 1: gradually increase the temperature in the furnace according to the mass percentage of the aluminum alloy, bake out the water vapor in the furnace, and during the heating process, put the A00 weighed according to the proportion on the side of the furnace for baking and then put it into the furnace to heat and melt;

[0045] Step 2: After A00 is dissolved, place the master alloy on the side of the furnace for baking and then put it into the furnace, stir it several times to fully dissolve it, and let it stand;

[0046] Step 3: Use a degasser to press the aluminum alloy sodium-free refining agent into the refining machine, pass 99.999% argon gas, degas, then remove the slag and let it stand;

[0047] Step 4: Check whether the aluminum alloy composition meets the use standard. If yes, proceed to step 5. If no, it means that a certain original mass percentage in the aluminum alloy liquid does not reach the preset mass percentage of the aluminum alloy. An additional element that does not reach the preset mass percentage is added so that the element that does not reach the preset mass percentage reaches the preset mass percentage, that is, the use standard is met.

[0048] Step 5: Detect the gas content, and when the density equivalent is ≤0.2%, proceed to step 6, otherwise continue the refining and degassing operation in step 3;

[0049] Step 6: Perform high pressure die casting through high pressure die casting equipment.

[0050] In a preferred embodiment, in step 1, the furnace side baking time of A00 is 30 minutes, the aluminum liquid temperature is set to 720°C, and the furnace temperature is set to 780°C.

[0051] In a preferred embodiment, in step 2, the furnace-side baking time of the intermediate alloy is 30 minutes, the intermediate alloy includes AlFe20, AlNi20, and AlRe20, and the standing time is 30 minutes.

[0052] In a preferred embodiment, in step 3, the refining agent ratio is 0.1% to 0.2%, and the degassing time is 15 minutes.

[0053] In a preferred embodiment, in step 6, the high pressure die casting equipment includes a vacuum system, an oil circulation mold temperature controller, and a barrel heating device.

[0054] In a preferred embodiment, in step 6, the process parameters of high pressure die casting are: mold cavity vacuum ≤ 50 Mbar, injection speed 2.5±0.5 m / s, mold temperature 130±10°C, and aluminum alloy liquid temperature 700±10°C.

[0055] Example 1

[0056] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 1.0 weight percent Fe, 0.05 weight percent Ni, 0.11 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.03 weight percent, Cr is 0.01 weight percent, V is 0.01 weight percent, and Ti is 0.008 weight percent.

[0057] A method for preparing the aluminum alloy of this embodiment comprises the following steps:

[0058] Step 1: gradually increase the temperature in the furnace according to the mass percentage of the aluminum alloy in this embodiment, bake out the water vapor in the furnace, and during the heating process, put the A00 weighed according to the proportion on the side of the furnace and bake for 30 minutes before putting it into the furnace to heat and melt. The aluminum liquid temperature is set to 720°C and the furnace temperature is set to 780°C;

[0059] Step 2: After A00 is dissolved, place the AlFe20, AlNi20, and AlRe20 master alloys by the furnace and bake for 30 minutes before putting them into the furnace, stirring several times to fully dissolve them and letting them stand for 30 minutes;

[0060] Step 3: Use a mobile rotary degasser to press the aluminum alloy sodium-free refining agent into the refining agent ratio of 0.1% to 0.2%, pass 99.999% argon gas, degas for 15 minutes, then skim the slag and let it stand;

[0061] Step 4: Detect whether the aluminum alloy composition reaches the preset mass percentage of the aluminum alloy in this embodiment by using an electric spark direct reading spectrometer. If so, proceed to step 5. If not, add elements that do not reach the preset mass percentage so that the elements that do not reach the preset mass percentage reach the preset mass percentage.

[0062] Step 5: Detect the gas content by a hydrogen detector, and when the density equivalent is ≤ 0.2%, proceed to step 6, otherwise continue the refining and degassing operation in step 3;

[0063] Step 6: High-pressure die-casting is performed using a LK 280T die-casting machine. The high-pressure die-casting equipment includes a vacuum system, an oil circulation mold temperature controller, and a barrel heating device. The process parameters of high-pressure die-casting are: mold cavity vacuum ≤50Mbar, injection speed 2.5±0.5m / s, mold temperature 130±10℃, and aluminum alloy liquid temperature 700±10℃.

[0064] Example 2

[0065] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 1.0 weight percent Fe, 0.10 weight percent Ni, 0.30 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.03 weight percent, Cr is 0.03 weight percent, V is 0.01 weight percent, and Ti is 0.01 weight percent.

[0066] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0067] Example 3

[0068] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 1.6 weight percent of Fe, 0.16 weight percent of Ni, 0.51 weight percent of La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.01 weight percent, Cr is 0.02 weight percent, V is 0.02 weight percent, and Ti is 0.02 weight percent.

[0069] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0070] Example 4

[0071] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 1.5 weight percent Fe, 0.31 weight percent Ni, 0.72 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.02 weight percent, Cr is 0.01 weight percent, V is 0.01 weight percent, and Ti is 0.009 weight percent.

[0072] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0073] Example 5

[0074] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 2.1 weight percent Fe, 0.50 weight percent Ni, 0.94 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.03 weight percent, Cr is 0.02 weight percent, V is 0.03 weight percent, and Ti is 0.007 weight percent.

[0075] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0076] Example 6

[0077] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 2.0 weight percent Fe, 0.70 weight percent Ni, 0.12 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.04 weight percent, Cr is 0.01 weight percent, V is 0.01 weight percent, and Ti is 0.01 weight percent.

[0078] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0079] Example 7

[0080] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 2.4 weight percent Fe, 0.85 weight percent Ni, 0.29 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.01 weight percent, Cr is 0.03 weight percent, V is 0.01 weight percent, and Ti is 0.02 weight percent.

[0081] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0082] Example 8

[0083] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 2.5 weight percent Fe, 0.97 weight percent Ni, 0.30 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.03 weight percent, Cr is 0.01 weight percent, V is 0.01 weight percent, and Ti is 0.008 weight percent.

[0084] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0085] Example 9

[0086] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 3.1 weight percent Fe, 0.05 weight percent Ni, 0.55 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.02 weight percent, Cr is 0.02 weight percent, V is 0.01 weight percent, and Ti is 0.007 weight percent.

[0087] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0088] Example 10

[0089] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 3.0 weight percent Fe, 0.15 weight percent Ni, 0.78 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.02 weight percent, Cr is 0.01 weight percent, V is 0.03 weight percent, and Ti is 0.009 weight percent.

[0090] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0091] Embodiment 11

[0092] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 3.6 weight percent Fe, 0.50 weight percent Ni, 0.85 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.01 weight percent, Cr are 0.02 weight percent, V are 0.02 weight percent, and Ti are 0.008 weight percent.

[0093] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0094] Example 12

[0095] A medium-strength high-conductivity voltage-cast aluminum alloy, the components and weight percentages of the aluminum alloy are: 4.0 weight percent Fe, 0.98 weight percent Ni, 0.98 weight percent La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight percent. Among them, the controlled impurity elements Mn are 0.03 weight percent, Cr is 0.03 weight percent, V is 0.01 weight percent, and Ti is 0.008 weight percent.

[0096] A method for preparing the aluminum alloy of this embodiment, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0097] Comparative Example 1

[0098] An aluminum alloy, the components and weight percentages of the aluminum alloy are: 1.0 weight % Fe, 0.05 weight % Ni, 0.11 weight % La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight %. Among them, the controlled impurity elements Mn are 0.31 weight %, Cr is 0.32 weight %, V is 0.24 weight %, and Ti is 0.13 weight %.

[0099] A method for preparing the aluminum alloy of this comparative example, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0100] Comparative Example 2

[0101] An aluminum alloy, the components and weight percentages of the aluminum alloy are: 1.6 weight % Fe, 0.16 weight % Ni, 0.51 weight % La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight %. Among them, the controlled impurity elements Mn are 0.51 weight %, Cr is 0.34 weight %, V is 0.20 weight %, and Ti is 0.23 weight %.

[0102] A method for preparing the aluminum alloy of this comparative example, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0103] Comparative Example 3

[0104] An aluminum alloy, the components and weight percentages of the aluminum alloy are: 2.5 weight % Fe, 0.97 weight % Ni, 0.30 weight % La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight %. Among them, the controlled impurity elements Mn are 0.45 weight %, Cr is 0.53 weight %, V is 0.31 weight %, and Ti is 0.17 weight %.

[0105] A method for preparing the aluminum alloy of this comparative example, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0106] Comparative Example 4

[0107] An aluminum alloy, the components and weight percentages of the aluminum alloy are: 3.0 weight % Fe, 2.5 weight % Ni, 0.05 weight % La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight %. Among them, the controlled impurity elements Mn are 0.45 weight %, Cr is 0.50 weight %, V is 0.31 weight %, and Ti is 0.20 weight %.

[0108] A method for preparing the aluminum alloy of this comparative example, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0109] Comparative Example 5

[0110] An aluminum alloy, the components and weight percentages of the aluminum alloy are: 4.5 weight % Fe, 3.0 weight % Ni, 0.03 weight % La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight %. Among them, the controlled impurity elements Mn are 0.53 weight %, Cr is 0.45 weight %, V is 0.35 weight %, and Ti is 0.24 weight %.

[0111] A method for preparing the aluminum alloy of this comparative example, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0112] Comparative Example 6

[0113] An aluminum alloy, the components and weight percentages of the aluminum alloy are: 4.5 weight % Fe, 4.5 weight % Ni, 0.45 weight % La and Ce, the weight ratio of La to Ce is 2:3, and the rest is Al and unavoidable impurity elements, and the single unavoidable impurity element is at most 0.05 weight %. Among them, the controlled impurity elements Mn are 0.04 weight %, Cr is 0.01 weight %, V is 0.03 weight %, and Ti is 0.03 weight %.

[0114] A method for preparing the aluminum alloy of this comparative example, the steps are the same as the method for preparing the aluminum alloy of Example 1.

[0115] For the above-mentioned embodiments and comparative examples, a 3mm×80mm×200mm flat mold test piece was prepared, and the conductivity of the material was measured using a direct-reading conductivity meter, and then converted into the international unit IACS. The test results are shown in Table 1:

[0116] Table 1:

[0117]

[0118] For the above examples and comparative examples, 3mm×80mm×200mm flat plate mold test pieces were prepared, and the mechanical properties were measured by Sansi tensile machine and imported extensometer, with a tensile rate of 1mm / s. The tensile test specimens were processed strictly in accordance with the proportional specimens in GB / T228.12010, and the test results are shown in Table 2:

[0119] Table 2:

[0120]

[0121]

[0122] It can be seen from the test results of Table 1 and Table 2 that the aluminum alloy materials of Examples 1 to 12 of the present invention have a tensile strength of 150-180 MPa in the cast state, a yield strength of 70-90 MPa, an elongation of 15-20%, and an electrical conductivity of 50-59% IACS. It can be seen that the aluminum alloy material provided by the present invention has excellent electrical conductivity and its strength can meet the standard, far exceeding the strength of pure aluminum.

[0123] From the test results of Table 1 and Table 2, it can be seen that the difference between the comparative example 1 provided by the present invention and the embodiment 1 is only that the weight percentages of the main impurity elements Mn, Cr, V, and Ti are different, the difference between the comparative example 2 and the embodiment 3 is only that the weight percentages of the main impurity elements Mn, Cr, V, and Ti are different, and the difference between the comparative example 3 and the embodiment 8 is only that the weight percentages of the main impurity elements Mn, Cr, V, and Ti are different. The conductivity of the comparative examples 1, 2, and 3 does not reach 50% IACS, and the conductivity of the embodiments 1, 3, and 8 is above 50% IACS. It can be seen that, first, when the Fe, Ni, La, and Ce elements meet the weight percentages recorded in the aluminum alloy of the present invention, the main impurity elements Mn, Cr, V, and Ti exceed the weight percentages recorded in the present invention, which will make the conductivity low and the conductive performance not up to standard. Second, the aluminum alloy provided by the present invention has excellent conductive performance by strictly controlling the content of the Mn, Cr, V, and Ti elements.

[0124] In Comparative Example 6, the weight percentage of the main impurity elements Mn, Cr, V, and Ti is controlled to be below 0.05%. The difference from Examples 1-12 is that the weight percentage of Fe and Ni elements exceeds the weight percentage recorded in the aluminum alloy of the present invention. The test results of Tables 1 and 2 show that the conductivity of Comparative Example 6 is only 38.1% IACS, far from 50% IACS, and the elongation at break is also not up to standard. It can be seen that, first, when the main impurity elements Mn, Cr, V, and Ti do not exceed the weight percentage recorded in the aluminum alloy of the present invention, the Fe, Ni, La, and Ce elements do not meet the weight percentage recorded in the present invention, which will result in low conductivity, substandard electrical conductivity, and substandard elongation at break. Second, the aluminum alloy material provided by the present invention uses specific Fe, Ni, La, and Ce elements and their weight percentages, which not only meets the standard strength, but also has excellent electrical conductivity.

[0125] The difference between Comparative Example 4 and Examples 1-12 is that the weight percentage of the Ni element exceeds the weight percentage recorded in the aluminum alloy of the present invention, the weight percentage of the La and Ce elements does not reach the weight percentage recorded in the aluminum alloy of the present invention, and the main impurity elements Mn, Cr, V, and Ti exceed the weight percentage recorded in the present invention. The difference between Comparative Example 5 and Examples 1-12 is that the weight percentage of the Fe and Ni elements exceeds the weight percentage recorded in the aluminum alloy of the present invention, the weight percentage of the La and Ce elements does not reach the weight percentage recorded in the aluminum alloy of the present invention, and the main impurity elements Mn, Cr, V, and Ti exceed the weight percentage recorded in the present invention. The test results of Tables 1 and 2 show that the conductivity of Comparative Example 4 is only 35.1% IACS, and the conductivity of Comparative Example 5 is only 35.5% IACS, both of which are far below 50% IACS. It can be seen that, first, when the Fe, Ni, La and Ce elements do not meet the weight percentages recorded in the present invention, and the main impurity elements Mn, Cr, V, and Ti exceed the weight percentages recorded in the aluminum alloy of the present invention, the conductivity will be low and the conductive performance will not meet the standards. Second, the aluminum alloy material provided by the present invention adopts specific Fe, Ni, La and Ce elements and their weight percentages, and strictly controls Mn, Cr, V, Ti elements to be below 0.05 weight %, while meeting the strength standards, it also has excellent electrical conductivity.

[0126] In combination with Comparative Examples 1-6 and Examples 1-12, it can be seen that, as described in the present invention, only when the Fe, Ni, La and Ce elements meet the weight percentages recorded in the present invention, and the main impurity elements Mn, Cr, V, Ti do not exceed the weight percentages recorded in the aluminum alloy of the present invention, can the aluminum alloy material have excellent electrical conductivity while meeting the strength standards.

[0127] The aluminum alloy provided by the present invention has excellent electrical conductivity by strictly controlling the contents of elements such as Mn, Cr, V, and Ti; the aluminum alloy material provided by the present invention adds appropriate amounts of Ce and La, improves the cast structure of the alloy, refines the grains, increases the strength of the material, and increases the electrical conductivity of the alloy; the aluminum alloy material provided by the present invention adopts specific Fe, Ni, La, and Ce elements and their weight percentages, and strictly controls Mn, Cr, V, and Ti elements, so that the tensile strength in the cast state reaches 150-180MPa, the yield strength reaches 70-90MPa, the elongation reaches 15-20%, and the electrical conductivity reaches 50-59% IACS, and has excellent electrical conductivity while far exceeding the strength of pure aluminum; the aluminum alloy material provided by the present invention has a low Ni content, greatly reduces the material price, and is helpful to promote the large-scale application of high-conductivity materials.

Claims

1. A medium-strength and high-conductivity voltage-cast aluminum alloy, characterized in that: The components and weight percentages of the aluminum alloy are: 1.0-4.0 wt% Fe, 0.05-0.85 wt% Ni, 0.1-0.78 wt% La and Ce, a single impurity element of up to 0.05 wt%, and the remainder Al.

2. The medium-strength and high-conductivity voltage-cast aluminum alloy according to claim 1, characterized in that: The impurity elements include Mn, Cr, V, and Ti.

3. The medium-strength and high-conductivity voltage-cast aluminum alloy according to claim 2, characterized in that: The Ti element is at most 0.02 wt%.

4. The medium-strength and high-conductivity voltage-cast aluminum alloy according to claim 1, characterized in that: The weight ratio of the La to the Ce is 2:

3.

5. The medium-strength and high-conductivity voltage-cast aluminum alloy according to claim 1, characterized in that: The aluminum alloy has a tensile strength of 150-180 MPa, a yield strength of 70-90 MPa, an elongation of 15-20%, and an electrical conductivity of 50-59% IACS in a cast state.

6. A method for preparing a medium-strength and high-conductivity voltage-cast aluminum alloy according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step (1): gradually heating the furnace according to the mass percentage of the aluminum alloy to bake out the water vapor in the furnace, and during the heating process, placing A00 weighed according to the proportion on the side of the furnace for baking and then putting it into the furnace to heat and melt; Step (2): After A00 is dissolved, the master alloy is placed on the side of the furnace for baking and then put into the furnace, stirred several times to fully dissolve and allowed to stand; Step (3): using a degasser to pressurize the aluminum alloy sodium-free refining agent for refining, introducing 99.999% argon gas, degassing, then slagging and standing; Step (4): Detect whether the aluminum alloy composition reaches the preset mass percentage of the aluminum alloy. If so, proceed to step (5). If not, add elements that do not reach the preset mass percentage so that the elements that do not reach the preset mass percentage reach the preset mass percentage. Step (5): Detect the gas content, and when the density equivalent is ≤ 0.2%, proceed to step (6); otherwise, continue the refining and degassing operation in step (3); Step (6): performing high pressure die casting using high pressure die casting equipment.

7. The method for preparing the medium-strength and high-conductivity voltage cast aluminum alloy according to claim 6, characterized in that: In the step (1), the furnace side baking time of A00 is 30 minutes, the aluminum liquid temperature is set to 720°C, and the furnace temperature is set to 780°C.

8. The method for preparing the medium-strength and high-conductivity voltage-cast aluminum alloy according to claim 6, characterized in that: In the step (2), the furnace-side baking time of the intermediate alloy is 30 minutes, the intermediate alloy is AlFe20, AlNi20, AlRe20, and the standing time is 30 minutes.

9. The method for preparing the medium-strength and high-conductivity voltage cast aluminum alloy according to claim 6, characterized in that: In the step (3), the refining agent ratio is 0.1% to 0.2%, and the degassing time is 15 minutes.

10. The method for preparing the medium-strength and high-conductivity voltage cast aluminum alloy according to claim 6, characterized in that: In the step (6), the high-pressure die-casting equipment includes a vacuum system, an oil circulation mold temperature controller, and a barrel heating device. The process parameters of the high-pressure die-casting are: mold cavity vacuum ≤50Mbar, injection speed 2.5±0.5m / s, mold temperature 130±10°C, and aluminum alloy liquid temperature 700±10°C.

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