High-strength and high-heat-resistance Al-Fe-Zr-Y alloy conductive material and preparation method thereof

Abstract

The invention discloses a high-strength and high-heat-resistance Al-Fe-Zr-Y alloy conductive material and a preparation method thereof.The material is prepared from, by weight, 0.5%-1.5% of Fe, 0.1%-0.2% of Zr, 0.05%-0.07% of Y and the balance aluminum; firstly, an alloy rod is obtained through gas-assisted continuous casting extrusion, the alloy rod contains an Al6Fe phase of dozens of nanometers to hundreds of nanometers and an alpha-Al matrix with high Y solid solubility, then a high-density nanoscale Al3 (Y, Zr) phase is formed through aging to stabilize the Al6Fe phase and improve the heat resistance of the alloy, and meanwhile, the Al6Fe phase and the Al3 (Y, Zr) phase cooperate to improve the strength level of the alloy; the conductive material is low in raw material cost, high in production efficiency and beneficial to popularization and application.

Description

Technical Field

[0001] The invention relates to a high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material and a preparation method thereof, belonging to the technical field of aluminum alloy processing and preparation. Background Art

[0002] The iron-containing phase in the Al-Fe alloy has high-temperature stability and can hinder the movement of grain boundaries to improve creep resistance. At the same time, the extremely low solid solubility of Fe in the aluminum matrix is ​​conducive to obtaining higher conductivity. Therefore, Al-Fe alloy is a heat-resistant aluminum alloy conductive material with great application prospects.

[0003] The commonly used preparation process for heat-resistant aluminum alloy conductive materials is casting. The aluminum alloy conductive materials prepared by casting have low strength, mainly because the iron-containing phase in the casting process is mainly coarse Al3Fe phase distributed along the grain boundary, which is mostly plate-like or long needle-like, resulting in reduced strength of the alloy; research has found that a faster cooling rate can refine the grains and form a metastable phase Al6Fe of tens of nanometers in the aluminum matrix. This phase has a coherent relationship with the aluminum matrix and is very beneficial to the improvement of the alloy strength. However, the Al6Fe phase formed at a high cooling rate will gradually coarsen when exposed to high-temperature heat, and eventually dissolve in the aluminum matrix, losing the strengthening effect, resulting in very poor heat resistance of the aluminum alloy conductive material; therefore, how to further improve the heat resistance of aluminum alloys containing Al6Fe phases while ensuring that the strength and conductivity of the aluminum alloys do not decrease significantly so that they have broader application prospects has become an urgent task. Summary of the invention

[0004] The object of the present invention is to provide a high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material and a preparation method thereof, so as to solve the problems existing in the prior art.

[0005] The technical solution of the present invention is as follows:

[0006] One of the purposes of the present invention is to provide a high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material, whose chemical composition by weight percentage is: Fe 0.5-1.5%, Zr 0.1-0.2%, Y 0.05-0.07%, and the balance is aluminum.

[0007] The second object of the present invention is to provide a method for preparing a high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material, which includes: material preparation, smelting, gas-assisted continuous casting and extrusion, and aging to obtain the conductive material, specifically including the following steps:

[0008] (1) According to their chemical compositions, weigh Al-10Fe, Al-5Zr, Al-5Y master alloys and high-purity aluminum ingots respectively.

[0009] (2) Al-10Fe, Al-5Zr, Al-5Y master alloy and high-purity aluminum ingots are charged into a furnace for melting and stirred until the mixture is uniform to complete the smelting.

[0010] Preferably, the melt temperature is maintained at 730-740°C during stirring.

[0011] (3) The specific process of gas-assisted continuous casting and extrusion is as follows: the molten metal flows into the extrusion wheel groove from the preheated funnel located above the extrusion wheel. Under the action of the inert gas, the molten metal spreads out closely along the groove wall of the extrusion wheel and begins to solidify. When the solidifying billet encounters a blockage, it begins to accumulate and gradually transfers into the die cavity, and is finally extruded from the die hole to form an alloy rod.

[0012] Preferably, the inner hole diameter of the funnel is 2-3 mm, and the funnel needs to be heated to 750-780° C. before pouring the alloy melt.

[0013] Preferably, the inert gas is nitrogen, and the gas pressure is 0.2-0.4 MPa.

[0014] Preferably, the rotation speed of the extrusion wheel is 8-12 rpm.

[0015] Preferably, the preheating temperature of the extrusion die cavity is 200-350° C., and the die hole diameter is 9.5 mm.

[0016] Preferably, the aging temperature is 280-300°C and the aging time is 50-100h.

[0017] The principle of the present invention is as follows: first, an alloy rod is obtained by gas-assisted continuous casting and extrusion, which contains an Al6Fe phase of tens to hundreds of nanometers and an α-Al matrix with a high Y solid solubility. Then, a high-density nanoscale Al3 (Y, Zr) phase is formed by aging to stabilize the Al6Fe phase and improve the heat resistance of the alloy. At the same time, the Al6Fe phase and the Al3 (Y, Zr) phase synergistically improve the strength level of the alloy.

[0018] Beneficial effects of the present invention:

[0019] (1) The solid solubility of Y in the gas-assisted continuous casting alloy rod is relatively high. During the aging process, the Y element can diffuse and aggregate at a lower temperature, thereby driving the diffusion of the Zr element to form the Al3(Y,Zr) phase. This process will not significantly change the morphology and size of the Al6Fe phase and α-Al grains.

[0020] (2) The Al3(Y,Zr) phase formed after aging can pin the Al6Fe phase boundary to prevent the coarsening of the Al6Fe phase during high-temperature service and improve the heat resistance of the alloy.

[0021] (3) The nanoscale Al3(Y,Zr) phase and the submicron-scale Al6Fe phase in the alloy can pin dislocations and jointly improve the strength level of the alloy; in addition, the alloying elements Fe, Zr and Y added in the present invention are low in price, which is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart for preparing high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive materials;

[0023] Figure 2 This is the principle diagram of gas-assisted continuous casting and extrusion.

[0024] In the figure: 1-funnel; 2-melt; 3-extrusion wheel; 4-extrusion wheel groove; 5-mold cavity; 6-mold; 7-extrusion rod; 8-injection device. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0026] The device used in the embodiment of the present invention is as follows Figure 2 As shown, it includes a funnel 1, an extrusion wheel 3, an extrusion wheel groove 4, a mold cavity 5, a mold 6, an extrusion rod 7, and an air jet device 8; the smelted metal melt 2 flows out from the preheated funnel 1 located above the extrusion wheel 3 to the extrusion wheel groove 4, and the air jet device 8 above the extrusion wheel groove sprays inert gas. Under the action of the inert gas, the melt spreads closely against the wall of the extrusion wheel groove and begins to solidify. Under the rotation of the extrusion wheel and the action of the plug on the mold cavity 5, the solidified billet is continuously extruded from the mold 6 to obtain a product alloy rod 7.

[0027] Example 1

[0028] The present invention relates to a method for preparing a high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material, comprising the following steps:

[0029] (1) Material preparation: The mass percentages are Fe: 0.5%, Zr: 0.2%, Y: 0.05%, and the balance is Al, which are called intermediate alloys such as Al-10Fe, Al-5Zr, Al-5Y, and high-purity aluminum ingots.

[0030] (2) Melting: Place the aluminum-iron master alloy, aluminum-zirconium master alloy aluminum ingot, aluminum-yttrium master alloy and aluminum ingot into a furnace for melting and stirring until the mixture is uniform. During the stirring process, the melt temperature is maintained at 740° C. Finally, the melt is kept at 730° C. for 60 minutes to complete the melting.

[0031] (3) Preparation of Al-Fe-Zr-Y alloy rod by gas-assisted continuous casting and extrusion: the molten alloy flows out from a funnel (funnel diameter is 2 mm) located above the extrusion wheel groove, and an inert gas (nitrogen gas, gas pressure is 0.2 MPa) is sprayed above the extrusion wheel groove. Under the combined action of gravity and the inert gas jet, the alloy melt spreads along the extrusion wheel groove to form a metal thin layer. Under the action of the extrusion wheel (rotation speed is 8 rpm) and the plug, the metal thin layer on the wheel groove wall continuously enters the mold and accumulates, and then is extruded from the mold hole to form an alloy rod; the mold cavity preheating temperature is 200°C, the funnel preheating temperature is 750°C, and the mold hole diameter is 9.5 mm.

[0032] (4) The alloy rod obtained in step (3) is subjected to a heat treatment at 280°C / 100h to obtain a high-performance Al-Fe-Zr-Y alloy rod: the tensile strength and electrical conductivity are 174MPa and 59.5%IACS, respectively.

[0033] (5) The alloy rod obtained in step (4) was subjected to a heat resistance test at 400°C / 1h, and its tensile strength was measured to be 165 MPa.

[0034] Example 2

[0035] The present invention relates to a method for preparing a high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material, comprising the following steps:

[0036] (1) Material preparation: The mass percentages are Fe: 1.0%, Zr 0.15%, Y 0.06%, and the balance is Al, which are called intermediate alloys such as Al-10Fe, Al-5Zr, and Al-5Y, and high-purity aluminum ingots.

[0037] (2) Melting: Charge the aluminum-iron master alloy, aluminum-zirconium master alloy, aluminum-yttrium master alloy and aluminum ingot into a furnace for melting and stirring until the mixture is uniform. During the stirring process, the melt temperature is maintained at 735°C. Finally, the melt temperature is maintained at 725°C for 60 minutes to complete the melting.

[0038] (3) Preparation of Al-Fe-Zr-Y alloy rod by gas-assisted continuous casting and extrusion: the molten alloy flows out from a funnel (funnel diameter is 2.8 mm) located above the extrusion wheel groove, and an inert gas (nitrogen gas, gas pressure is 0.3 MPa) is sprayed above the extrusion wheel groove. Under the combined action of gravity and the inert gas jet, the alloy melt spreads along the extrusion wheel groove to form a metal thin layer. Under the action of the extrusion wheel (rotation speed is 10 rpm) and the plug, the metal thin layer on the wheel groove wall continuously enters the mold and accumulates, and then is extruded from the mold hole to form an alloy rod; the mold cavity preheating temperature is 280°C, the funnel preheating temperature is 770°C, and the mold hole diameter is 9.5 mm.

[0039] (4) The alloy rod obtained in step (3) is subjected to a heat treatment at 290° C. for 70 h to obtain a high-performance Al-Fe-Zr-Y alloy conductive material: the tensile strength and conductivity are 181 MPa and 58.8% IACS, respectively.

[0040] (5) The alloy rod obtained in step (4) was subjected to a heat resistance test at 400°C / 1h, and its tensile strength was measured to be 168 MPa.

[0041] Example 3

[0042] The present invention relates to a method for preparing a high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material, comprising the following steps:

[0043] (1) Material preparation: The mass percentages are Fe: 1.5%, Zr: 0.1%, Y: 0.07%, and the balance is Al, which are called intermediate alloys such as Al-10Fe, Al-5Zr, Al-5Y, and high-purity aluminum ingots.

[0044] (2) Melting: Charge the aluminum-iron master alloy, aluminum-zirconium master alloy, aluminum-yttrium master alloy and aluminum ingot into a furnace for melting and stirring until the mixture is uniform. During the stirring process, the melt temperature is maintained at 730° C. Finally, the melt temperature is maintained at 720° C. for 60 minutes to complete the melting.

[0045] (3) Preparation of Al-Fe-Zr-Y alloy rod by gas-assisted continuous casting and extrusion: the molten alloy flows out from a funnel (funnel diameter is 3 mm) located above the extrusion wheel groove, and an inert gas (nitrogen gas, gas pressure is 0.4 MPa) is sprayed above the extrusion wheel groove. Under the combined action of gravity and the inert gas jet, the alloy melt spreads along the extrusion wheel groove to form a metal thin layer. Under the action of the extrusion wheel (rotation speed is 12 rpm) and the plug, the metal thin layer on the wheel groove wall continuously enters the mold and accumulates, and then is extruded from the mold hole to form an alloy rod; the mold cavity preheating temperature is 350°C, the funnel preheating temperature is 780°C, and the mold hole diameter is 9.5 mm.

[0046] (4) The alloy rod obtained in step (3) is subjected to a heat treatment at 300°C for 50 h to obtain a high-performance Al-Fe-Zr-Y alloy conductive material: the tensile strength and conductivity are 187 MPa and 58.3% IACS, respectively.

[0047] (5) The alloy rod obtained in step (4) was subjected to a heat resistance test at 400°C / 1h, and its tensile strength was measured to be 172 MPa.

[0048] Comparative Example 1

[0049] (1) Material preparation: The mass percentages are as follows: Fe: 0.5%; Zr 0.2%; Y 0.05%; the balance is Al, which are called intermediate alloys such as Al-10Fe, Al-5Zr, Al-5Y, and high-purity aluminum ingots.

[0050] (2) Melting: Charge the aluminum-iron master alloy, aluminum-zirconium master alloy, aluminum-yttrium master alloy and aluminum ingot into a furnace for melting and stirring until the mixture is uniform. During the stirring process, the melt temperature is maintained at 740°C. Finally, the melt temperature is maintained at 730°C for 60 minutes to complete the melting.

[0051] (3) Casting: The molten metal in step (2) is cast to prepare an aluminum-iron alloy rod with a diameter of 9.5 mm.

[0052] (4) The alloy rod obtained in step (3) was subjected to a heat treatment at 280° C. / 100 h. After the heat treatment, the tensile strength and electrical conductivity were 127 MPa and 60.7% IACS, respectively.

[0053] (5) The alloy rod obtained in step (4) was subjected to a heat resistance test at 400°C / 1h, and its tensile strength was measured to be 123 MPa.

[0054] Comparative Example 2

[0055] The steps and conditions of this embodiment are the same as those of embodiment 1, except that: Zr and Y are not added, that is, the materials are prepared as follows: Fe: 1.0%; the remainder is Al, which are respectively called Al-10Fe alloy and high-purity aluminum ingot.

[0056] After heat treatment, the tensile strength and electrical conductivity of the alloy rod obtained were 130 MPa and 61.3% IACS, respectively.

[0057] The obtained alloy rod was subjected to a heat resistance test at 400°C / 1h, and its tensile strength was measured to be 90MPa.

[0058] By comparing Examples 1 and 2 with Comparative Examples 1 and 2, it can be seen that the alloy prepared by the present invention has a more excellent combination of strength, conductivity and heat resistance, and can meet the requirements of ultra-heat-resistant aluminum alloy wires, mainly due to the refinement of the iron-rich phase and the suppression of the coarsening of the Al6Fe phase by the nanoscale Al3(Y,Zr) phase.

Claims

1. A high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material, characterized in that: Calculated by weight percentage, its chemical composition is: Fe 0.5-1.5%, Zr 0.1-0.2%, Y 0.05-0.07%, and the balance is aluminum.

2. A method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material as claimed in claim 1, characterized in that: The specific steps include: (1) Material preparation: Al-10Fe, Al-5Zr, Al-5Y master alloys and high-purity aluminum ingots were weighed according to their chemical compositions; (2) Melting: Al-10Fe, Al-5Zr, Al-5Y master alloy and high-purity aluminum ingot are placed in a furnace for melting, and stirred until the mixture is uniform to complete the melting; (3) preparing alloy rods by gas-assisted continuous casting and extrusion; (4) Isothermal aging is performed on the alloy rod obtained in step (3) to obtain a conductive material.

3. The method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material according to claim 2, characterized in that: During stirring in step (2), the melt temperature is maintained at 730-740°C.

4. The method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material according to claim 2, characterized in that: In step (3), the specific process of gas-assisted continuous casting and extrusion is as follows: the smelted metal melt flows into the extrusion wheel groove from the preheated funnel located above the extrusion wheel. Under the action of the inert gas, the melt spreads out closely against the wall of the extrusion wheel groove and begins to solidify. After encountering a blockage, the solidifying billet begins to accumulate and gradually transfers into the extrusion die cavity, and is finally extruded from the die hole to form an alloy rod.

5. The method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material according to claim 4, characterized in that: In step (3), the inner hole diameter of the funnel is 2-3 mm, and the funnel needs to be heated to 750-780° C. before pouring the alloy melt.

6. The method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material according to claim 4, characterized in that: In step (3), the inert gas is nitrogen and the gas pressure is 0.2-0.4 MPa.

7. The method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material according to claim 4, characterized in that: The rotation speed of the extrusion wheel in step (3) is 8-12 rpm.

8. The method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material according to claim 4, characterized in that: In step (3), the preheating temperature of the extrusion die cavity is 200-350°C, and the die hole diameter is 9.5 mm.

9. The method for preparing the high-strength and high-heat-resistant Al-Fe-Zr-Y alloy conductive material according to claim 2, characterized in that: The aging temperature in step (4) is 280-300°C and the aging time is 50-100h.

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