阅读说明：本技术 一种低温用铝合金 (Aluminum alloy for low temperature ) 是由 魏海根 张真 夏承东 吴勇 龙昌 于 2021-09-30 设计创作，主要内容包括：本发明公开了一种低温用铝合金,属于合金材料技术领域,该低温用铝合金包括如下原料：Si、Fe、Cu、Mg、Mn、Zn、Ti、Zr、V、Cd、Sn以及Al,本发明使用多种元素进行合金的制备,通过熔炼铸造,均匀化处理、挤压成型,固溶热处理,时效处理等步骤制成,本发明在制备时添加的锰具有辅助强化的作用,同时还有助于控制合金中晶粒的大小,钛、锆、钒一起使用,可以有效控制晶粒,防止应力腐蚀,同时锆和铜一起使用可以有效的改善合金的低温韧性,本发明添加多种元素,优化制备工艺制备出的铝合金,不仅常温下具备良好的机械强度,且在低温下也具有较高的屈服强度,且缺口韧性受温度影响较小,仍然保持着良好的机械性能。(The invention discloses an aluminum alloy for low temperature, which belongs to the technical field of alloy materials and comprises the following raw materials: the invention relates to a preparation method of an aluminum alloy, which comprises the following steps of Si, Fe, Cu, Mg, Mn, Zn, Ti, Zr, V, Cd, Sn and Al, wherein multiple elements are used for preparing the alloy, and the alloy is prepared by smelting and casting, homogenizing treatment, extrusion forming, solid solution heat treatment, aging treatment and other steps.)

1. The low-temperature aluminum alloy is characterized by comprising the following raw materials in percentage by weight: si: 0.01% -0.2%, Fe: 0.01% -0.3%, Cu: 5.3% -6.8%, Mg: 0.01% -0.2%, Mn: 0.2% -0.4%, Zn: 0.01% -1%, Ti: 0.06% -0.12%, Zr: 0.15% -0.25%, V: 0.1% -0.15%, Cd: 0.05% -0.2%, Sn: 0.03 to 0.08 percent of Al, and the balance of Al.

2. The aluminum alloy for low temperature use according to claim 1, which is produced by the steps of:

step S1: adding aluminum into a smelting furnace, heating to 700-780 ℃ to be melted into aluminum liquid, and then carrying out slag removing treatment;

step S2: starting electromagnetic stirring by a smelting furnace, heating aluminum liquid to 1250 ℃, adding copper into the smelting furnace, smelting for 20min, then continuously adding cadmium and tin, heating to 1600 ℃ after melting, sequentially adding silicon, iron, magnesium, titanium and zinc into the smelting furnace, heating to 1900-1950 ℃ after melting, sequentially adding vanadium, zirconium and manganese, smelting for 1-2h, then cooling to 780-850 ℃ for dispersion treatment for 5-10min, then carrying out homogenization treatment, and carrying out extrusion molding at 400 ℃ after homogenization treatment to obtain an alloy blank;

step S3: and carrying out solution heat treatment on the alloy blank, rapidly quenching the alloy blank by using water with the temperature of 20-25 ℃ after the solution heat treatment, then carrying out aging treatment for 4h, and naturally cooling to obtain the low-temperature aluminum alloy.

3. The aluminum alloy for low temperature use according to claim 2, wherein the dispersion treatment in step S2 is an ultrasonic external field treatment under conditions of a current intensity of 4 to 4.5A and an output frequency of 18 to 20 KHz.

4. The aluminum alloy for low temperature use according to claim 2, wherein the homogenization treatment in step S2 is carried out at a temperature of 485 ℃ for a treatment time of 24 hours.

5. The aluminum alloy for low temperature use according to claim 2, wherein the extrusion speed in the extrusion molding in the step S2 is 1 to 3 mm/S.

6. The aluminum alloy for low temperature use as claimed in claim 2, wherein the temperature of the solution heat treatment in the step S3 is 500 ℃ and the time is 1 hour.

7. The aluminum alloy for low temperature use according to claim 2, wherein the aging treatment in step S3 is artificial aging at 200 ℃.

8. The aluminum alloy for low temperature use according to claim 2, wherein the steps S1 and S2 are performed under the condition of introducing argon gas.

Technical Field

The invention relates to the technical field of alloy materials, in particular to an aluminum alloy for low temperature.

Background

The aluminum element is second to oxygen and silicon in the earth crust, and is the most abundant metal element in the earth crust, and is mainly present as aluminosilicate ore. Among the metal species, aluminum is the second metal to steel and is the second largest metal.

The aluminum alloy is an alloy which takes aluminum as a base material and is added with a certain amount of other alloying elements, is one of light metal materials, has higher strength, good casting performance and plastic processing performance, good electric conduction and heat conduction performance, good corrosion resistance and weldability, and is widely used in the industries of automobile engines, transmissions, aviation equipment, other mechanical equipment and the like, but the existing aluminum alloys such as aluminum-zinc-copper aluminum alloys 7075 and 7079 have very high strength, but are easy to generate embrittlement phenomenon at low temperature, and the mechanical properties such as plasticity, toughness and the like are sharply reduced, so that the application range of the aluminum alloys is limited.

Disclosure of Invention

The invention aims to provide an aluminum alloy for low temperature, which is used for solving the problems in the background technology.

The purpose of the invention can be realized by the following technical scheme:

the low-temperature aluminum alloy comprises the following raw materials in percentage by weight: si: 0.01% -0.2%, Fe: 0.01% -0.3%, Cu: 5.3% -6.8%, Mg: 0.01% -0.2%, Mn: 0.2% -0.4%, Zn: 0.01% -1%, Ti: 0.06% -0.12%, Zr: 0.15% -0.25%, V: 0.1% -0.15%, Cd: 0.05% -0.2%, Sn: 0.03 to 0.08 percent of Al, and the balance of Al.

As a further scheme of the invention: the low-temperature aluminum alloy is prepared by the following steps:

step S1: adding aluminum into a smelting furnace, heating to 700-780 ℃ to be melted into aluminum liquid, and then carrying out slagging-off treatment;

step S2: starting electromagnetic stirring by a smelting furnace, heating aluminum liquid to 1250 ℃, adding copper into the smelting furnace, smelting for 20min, then continuously adding cadmium and tin, heating to 1600 ℃ after melting, sequentially adding silicon, iron, magnesium, titanium and zinc into the smelting furnace, heating to 1900-;

step S3: and carrying out solution heat treatment on the alloy blank, controlling the temperature to be 500 ℃, carrying out solution time for 1h, carrying out rapid quenching by using water at the temperature of 20-25 ℃ after the solution heat treatment, then heating to 200 ℃ again, carrying out artificial aging treatment for 4h, and naturally cooling to obtain the low-temperature aluminum alloy.

As a further scheme of the invention: in step S2, ultrasonic external field treatment is adopted for the dispersion treatment, the conditions of the ultrasonic external field treatment are that the current intensity is 4-4.5A, and the output frequency is 18-20 KHz.

As a further scheme of the invention: the extrusion speed in the extrusion molding in the step S2 is 1-3 mm/S.

As a further scheme of the invention: step S1 and step S2 were performed under argon gas.

The invention provides an aluminum alloy for low temperature, which has the following beneficial effects compared with the prior art:

(1) the invention uses a plurality of elements to prepare the alloy, realizes hardening through aluminum-copper phase transformation and transfer, and adds cadmium and tin to accelerate the nucleation process of the aluminum-copper phase during preparation; the added manganese has the function of auxiliary reinforcement and is also beneficial to controlling the size of crystal grains in the alloy; the added titanium is a grain refiner, can effectively improve the surface quality of the casting, enables the casting to obtain fine isometric crystals, can effectively overcome casting cracks and improve the appearance of the casting, can effectively control grains and prevent stress corrosion when the titanium, the zirconium and the vanadium are used together, and can effectively improve the low-temperature toughness of the alloy when the zirconium and the copper are used together.

(2) The invention carries out homogenization treatment before extrusion molding, can change the internal structure and performance of the alloy so as to be beneficial to subsequent extrusion, and can improve the internal crystalline structure of the alloy, eliminate casting stress and reduce segregation; and the solution heat treatment is carried out at 500 ℃, cold water is used for rapid quenching after the heat treatment, and then the aging treatment at 200 ℃ is carried out, so that the strength is ensured and the straightening is easy.

(3) According to the invention, multiple elements are added, the preparation process is optimized, the aluminum alloy is prepared, the aluminum alloy has good mechanical strength at normal temperature, high yield strength at low temperature, small influence on notch toughness by temperature, good mechanical property at low temperature and wider application range.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

An aluminum alloy for low temperature use, which is produced by the steps of:

introducing argon into the smelting furnace, adding 94.26kg of aluminum into the smelting furnace, heating to 700 ℃ to melt the aluminum into aluminum liquid, and then carrying out slagging-off treatment; starting electromagnetic stirring by a smelting furnace after slagging-off treatment, simultaneously heating aluminum liquid to 1250 ℃, then adding 5.3kg of copper into the smelting furnace, smelting for 20min, then continuously adding 0.05kg of cadmium and 0.03kg of tin, heating to 1600 ℃ after melting, sequentially adding 0.01kg of silicon, 0.01kg of iron, 0.01kg of magnesium, 0.06kg of titanium and 0.01kg of zinc into the smelting furnace, heating to 1900 ℃ after melting, sequentially adding 0.1kg of vanadium, 0.15kg of zirconium and 0.01kg of manganese, smelting for 1h, then reducing the temperature to 780 ℃, performing dispersion treatment for 5min by adopting ultrasonic external field treatment, controlling the condition of the ultrasonic external field treatment to be 4A in current intensity and 18KHz in output frequency, cooling to 485 ℃ after dispersion treatment, performing homogenization treatment for 24h at the temperature, performing extrusion forming at 400 ℃ and the extrusion speed of 1mm/s after homogenization treatment, and preparing an alloy blank; and then carrying out solution heat treatment on the alloy blank for 1h at the temperature of 500 ℃, rapidly quenching the alloy blank by using water at the temperature of 20 ℃ after the solution heat treatment, heating to 200 ℃ again after quenching, carrying out artificial aging treatment for 4h, and naturally cooling to obtain the low-temperature aluminum alloy.

Example 2

An aluminum alloy for low temperature use, which is produced by the steps of:

introducing argon into the smelting furnace, adding 92.815kg of aluminum into the smelting furnace, heating to 700 ℃ to melt the aluminum into aluminum liquid, and then carrying out slagging-off treatment; starting electromagnetic stirring by the smelting furnace after slagging-off treatment, simultaneously heating molten aluminum to 1250 ℃, then adding 6.1kg of copper into the smelting furnace, smelting for 20min, then continuously adding 0.12kg of cadmium and 0.05kg of tin, heating to 1600 ℃ after melting, sequentially adding 0.1kg of silicon, 0.15kg of iron, 0.1kg of magnesium, 0.09kg of titanium and 0.05kg of zinc into the smelting furnace, heating to 1925 ℃ after melting, sequentially adding 0.125kg of vanadium, 0.2kg of zirconium and 0.1kg of manganese, smelting for 1.5h, then cooling to 815 ℃, performing dispersion treatment by adopting ultrasonic external field treatment for 7.5min, controlling the condition of the ultrasonic external field treatment to be 4.2A in current intensity, outputting frequency to 19KHz, cooling to 485 ℃ after dispersion treatment, performing homogenization treatment for 24h at the temperature, and performing extrusion forming at 400 ℃ and extrusion speed of 2mm/s after homogenization treatment to obtain an alloy blank; and then carrying out solution heat treatment on the alloy blank for 1h at the temperature of 500 ℃, rapidly quenching the alloy blank by using water at the temperature of 23 ℃ after the solution heat treatment, heating the quenched alloy blank to 200 ℃ again for artificial aging treatment for 4h, and naturally cooling the quenched alloy blank to obtain the low-temperature aluminum alloy.

Example 3

An aluminum alloy for low temperature use, which is produced by the steps of:

introducing argon into the smelting furnace, adding 90.5kg of aluminum into the smelting furnace, heating to 700 ℃ to melt the aluminum into aluminum liquid, and then carrying out slagging-off treatment; starting electromagnetic stirring by a smelting furnace after slagging-off treatment, simultaneously heating molten aluminum to 1250 ℃, then adding 6.8kg of copper into the smelting furnace, smelting for 20min, then continuously adding 0.2kg of cadmium and 0.08kg of tin, heating to 1600 ℃ after melting, sequentially adding 0.2kg of silicon, 0.3kg of iron, 0.2kg of magnesium, 0.12kg of titanium and 1kg of zinc into the smelting furnace, heating to 1950 ℃ after melting, sequentially adding 0.15kg of vanadium, 0.25kg of zirconium and 0.2kg of manganese, smelting for 2h, then cooling to 850 ℃, performing dispersion treatment for 10min by adopting ultrasonic external field treatment, controlling the condition of the ultrasonic external field treatment to be 4.5A in current intensity, 20KHz in output frequency, cooling to 485 ℃ after dispersion treatment, performing homogenization treatment for 24h at the temperature, performing extrusion forming at 400 ℃ and extrusion speed of 3mm/s after homogenization treatment, and preparing an alloy blank; and then carrying out solution heat treatment on the alloy blank at the temperature of 500 ℃ for 1h, carrying out solution heat treatment, then rapidly quenching by using water at the temperature of 25 ℃, heating to 200 ℃ again after quenching for artificial aging treatment for 4h, and naturally cooling to obtain the low-temperature aluminum alloy.

Comparative example: 7075 aluminium alloy.

The aluminium alloys of examples 1 to 3 and comparative example were processed to 13mm thick plates and then tested for properties according to standard GB6397-86, giving the results shown in the following table:

as can be seen from the above table, the tensile strength of examples 1-3 is slightly higher than that of comparative examples at 25 ℃, the tensile limit is still increased with decreasing temperature, the low-temperature performance is good, the yield strength still has a higher index at low temperature, the elongation changes less with decreasing temperature, the low-temperature toughness is good, and the low-temperature notch toughness is less affected by temperature as can be seen from the ratio of notch tensile strength/non-notch tensile strength.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.