阅读说明：本技术 一种高导耐热抗蠕变的铝合金导体材料及制备方法和应用 (High-conductivity heat-resistant creep-resistant aluminum alloy conductor material and preparation method and application thereof ) 是由 李红英 席志海 靳东 杨长龙 胡博 金鹏 李希元 李小兰 谭澈 于 2020-11-30 设计创作，主要内容包括：本发明涉及一种高导耐热抗蠕变的铝合金导体材料及制备方法和应用,所述导体材料以质量百分比计包括下述组分：Zr:0.02～0.10％、Cu:0.04～0.12％、Ni:0.02～0.06％、La:0.05～0.15％、Y:0.005～0.020％,余量为Al和不可避免的杂质元素；所述制备方法包括配料、熔炼、铸造、变形、热处理。本发明提供的铝合金导体材料具有高导电率并兼顾良好的耐热和抗蠕变性能,20℃的导电率大于60.4％IACS,短期(1h)耐热温度为250℃,长期(400h)耐热温度为210℃,在210℃及30MPa应力条件下的稳态蠕变速率不超过1.79×10~(-7)s~(-1)。本发明所设计和制备的材料可以作为导电材料使用,所述导电材料包括但不限于导线、母线、导杆、电线、电缆,特别适用于制备服役温度较高的导电材料。(The invention relates to a high-conductivity heat-resistant creep-resistant aluminum alloy conductor material, a preparation method and application thereof, wherein the conductor material comprises the following components in percentage by mass: 0.02-0.10% of Zr, 0.04-0.12% of Cu, 0.02-0.06% of Ni, 0.05-0.15% of La, 0.005-0.020% of Y and the balance of Al and inevitable impurity elements; the preparation method comprises the steps of material preparation, smelting, casting, deformation and heat treatment. The aluminum alloy conductor material provided by the invention has high conductivity and good heat resistance and creep resistance, the conductivity at 20 ℃ is more than 60.4% IACS, the short-term (1h) heat-resistant temperature is 250 ℃, the long-term (400h) heat-resistant temperature is 210 ℃, and the steady-state creep rate under the stress conditions of 210 ℃ and 30MPa is not more than 1.79 multiplied by 10 ‑7 s ‑1 . The material designed and prepared by the invention can be used as a conductive material, and the conductive material comprises but is not limited to wires, buses, guide rods, wires, cables and the likeIs not suitable for preparing conductive materials with higher service temperature.)

1. The high-conductivity heat-resistant creep-resistant aluminum alloy conductor material is characterized by comprising the following components in percentage by mass:

Zr:0.02～0.10％；

Cu:0.04～0.12％；

Ni:0.02～0.06％；

La:0.05～0.15％；

Y:0.005～0.020％；

the content of impurity element Si is less than or equal to 0.05 percent;

the total content of other impurities is less than or equal to 0.01 percent, and the other impurities comprise at least one of Ti, V, Cr, Mn, Zn and Ca;

the balance being Al.

2. The aluminum alloy conductor material with high conductivity, heat resistance and creep resistance as claimed in claim 1, wherein the aluminum alloy comprises the following components in percentage by mass:

Zr:0.03～0.08％；

Cu:0.05～0.10％；

Ni:0.02～0.04％；

La:0.10～0.15％；

Y:0.005～0.010％；

the content of impurity element Si is less than or equal to 0.05 percent;

the total content of other impurities is less than or equal to 0.01 percent, and the other impurities comprise at least one of Ti, V, Cr, Mn, Zn and Ca;

the balance being Al.

3. The aluminum alloy conductor material with high conductivity, heat resistance and creep resistance as claimed in claim 1, wherein the mass ratio of Cu to Ni in the aluminum alloy is 2.0-2.5.

4. A preparation method of a high-conductivity heat-resistant creep-resistant aluminum alloy conductor material is characterized by comprising the following steps of firstly, preparing raw materials according to design components, smelting, carrying out rapid component analysis and component adjustment in front of a furnace, and then obtaining a bus, a guide rod, a casting blank or a continuous casting blank through casting; the bus and the guide rod obtained by casting can be used as finished products, and the performance can be further improved by heat treatment; the casting blank can be extruded to obtain a bus bar and a guide rod; the continuous casting blank can be continuously rolled to obtain a wire blank, and then is subjected to heat treatment and drawing.

5. The method as claimed in claim 4, wherein the extrusion temperature is 380-420 ℃, and the extrusion ratio λ is greater than 6.

6. The method as claimed in claim 4, wherein the continuous rolling temperature is 470-520 ℃, and the aluminum alloy conductor material is rapidly cooled after the final rolling.

7. The method for preparing the aluminum alloy conductor material with high conductivity, heat resistance and creep resistance as claimed in claim 4, wherein the heat treatment comprises pre-aging and aging; the pre-aging temperature is 380-430 ℃, and the pre-aging time is 5-10 h; the aging temperature is 250-300 ℃, and the aging time is 18-24 h.

8. The method for preparing the aluminum alloy conductor material with high conductivity, heat resistance and creep resistance as claimed in claim 4, wherein the drawing deformation is determined according to the strength of the product, and the deformation is preferably greater than or equal to 90%.

9. The method for preparing the aluminum alloy conductor material with high conductivity, heat resistance and creep resistance as claimed in any one of claims 4 to 8, wherein the obtained aluminum alloy conductor material has an electrical conductivity of more than 60.4% IACS at 20 ℃, a short-term (1h) heat-resistant temperature of 250 ℃, a long-term (400h) heat-resistant temperature of 210 ℃, and a steady-state creep rate of 1.79 x 10 or less under the stress conditions of 210 ℃ and 30MPa^-7s^-1。

10. Use of the high conductivity, heat resistance and creep resistance aluminum alloy conductor material according to any of claims 1-3, wherein the use includes but is not limited to use as a conductive material.

Technical Field

The invention belongs to the technical field of metallurgical materials, and relates to a high-conductivity heat-resistant creep-resistant aluminum alloy conductor material, and a preparation method and application thereof.

Technical Field

The power demand and power resources among China regions are seriously unbalanced, and the power resources need to be transmitted to a power load concentration region from the enrichment region through long-distance large-capacity power transmission, but the power loss of a power transmission line is increased along with the increase of the transmission distance. In the electric energy loss of the electric transmission line, the electric energy loss caused by conductor resistance accounts for more than 80%, the conductivity is improved by 1% IACS, and the electric loss of each kilometer of the line is averagely reduced by about 2000 degrees every year. As transmission capacity increases, the service temperature of the conductor increases, resulting in a reduction in tensile strength, thermal elongation and creep, which can cause problems, such as a significant increase in conductor sag, resulting in a conductor that does not meet safety requirements for ground distance or for spans.

The ultra-high voltage and long-distance power transmission technology in China is in the international leading position, but the development of the aluminum conductor material for the overhead power transmission line is limited by the comprehensive performance level. In practical application, the transmission capacity of a transmission line is generally limited or a heat resistance requirement is provided for a conductor material, so that the conductor material can have sufficient strength survival rate and creep resistance at the service temperature. Therefore, as a conductor material for a long-distance, large-capacity, low-loss transmission line, not only high electrical conductivity at normal temperature but also high electrical conductivity at service temperature, heat resistance and creep resistance are required. However, in the prior art, the conductivity and other performance indexes are difficult to be improved synergistically, so that the development of the high-conductivity, heat-resistant and creep-resistant aluminum alloy conductor material is the key point for breaking through the bottleneck of further development of the power transmission technology in China.

The patent with the publication number of CN108559874A discloses a high-strength high-conductivity heat-resistant aluminum alloy wire, the disclosed conductivity reaches 62% IACS, the long-term operation temperature can reach 210 ℃, but the technical scheme does not relate to the creep resistance of the alloy, and the production cost is increased due to the high content of Zr and Ce elements.

The patent with publication number CN108359861A discloses a high-conductivity heat-resistant creep-resistant aluminum alloy and a preparation method thereof, the technical scheme discloses that the normal-temperature conductivity is only 60.17% IACS, and the long-term heat-resistant temperature is only 180 ℃.

The patent with publication number CN110310755A discloses a creep-resistant aluminum alloy conductor and a preparation method thereof, the technical scheme does not relate to the heat resistance of the alloy, and the added elements are more in variety, which results in increased production cost and more complex preparation process.

Compared with the prior art, the aluminum alloy conductor material with high conductivity, heat resistance and creep resistance is developed by optimizing the aluminum alloy components and the preparation process, is suitable for preparing overhead conductors, can also be used for manufacturing buses and guide rods, and can also be used for preparing wires and cables with higher service temperature.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the high-conductivity heat-resistant creep-resistant aluminum alloy conductor material and the preparation scheme thereof, and the prepared aluminum alloy has good conductivity, heat resistance and creep resistance and also has the advantage of lower production cost.

The invention aims to overcome the defects in the prior art and provide a composition design scheme of an aluminum alloy conductor material with high conductivity, heat resistance and creep resistance.

The invention relates to a high-conductivity heat-resistant creep-resistant aluminum alloy conductor material, which comprises the following components in percentage by mass:

Zr：0.02～0.10％；

Cu：0.04～0.12％；

Ni：0.02～0.06％；

La：0.05～0.15％；

Y：0.005～0.020％；

the total content of impurity element Si is less than or equal to 0.05 percent;

the total content of other impurity elements such as Ti, V, Cr, Mn, Zn, Ca and the like is less than or equal to 0.01 percent;

the balance being Al.

In the present invention, the content of Zr is 0.02 to 0.10 wt.%, preferably 0.03 to 0.08 wt.%, specifically, such as 0.03 wt.%, 0.04 wt.%, 0.05 wt.%, 0.06 wt.%, 0.07 wt.%, 0.08 wt.%; when the Zr content is lower than 0.02 percent, second phase particles containing Zr are difficult to form, grain boundaries are easy to move at higher temperature, and the heat resistance and the creep resistance of the aluminum alloy can not meet the requirements; when the Zr content exceeds 0.10 wt.%, there may be primary Al₃Zr is generated, so that grain refinement leads to increase of grain boundary area, and although the heat resistance of the alloy is improved, the electric conductivity of the alloy is greatly damaged.

In the present invention, the content of Cu is 0.04 to 0.12 wt.%, preferably 0.05 to 0.10 wt.%, specifically, such as 0.05 wt.%, 0.06 wt.%, 0.07 wt.%, 0.08 wt.%, 0.09 wt.%, 0.10 wt.%; the Cu content is more than or equal to 0.04 wt.%, so that the strength of the industrial pure aluminum can be effectively improved, and the alloy has excellent heat resistance; when the Cu content exceeds 0.12 wt.%, it results in a significant decrease in the conductive properties of the aluminum alloy, particularly when it exists in a solid solution state.

In the present invention, the content of Ni is 0.02 to 0.06 wt.%, preferably 0.02 to 0.04 wt.%, specifically, such as 0.02 wt.%, 0.03 wt.%, 0.04 wt.%; ni element content of 0.02 wt.% or more, and forming Al-Cu-Ni phase by synergistic action with Cu element, such as beta-Al₇Cu₄Ni、δ-Al₃CuNi can improve the thermal stability of the alloy; when the Ni content exceeds 0.06 wt.%, the conductive properties of the alloy are negatively affected.

According to the invention, the content ratio of Cu and Ni elements is controlled to be 2.0-2.5, the synergistic effect between the Cu and Ni elements can be fully exerted, the formation of an aluminum-copper-nickel phase is promoted, the solid solution degree of the Cu and Ni elements is reduced, and the alloy has good heat resistance and conductivity.

In the present invention, the content of La is 0.05 to 0.15 wt.%, preferably 0.10 to 0.15 wt.%, specifically, such as 0.10 wt.%, 0.11 wt.%, 0.12 wt.%, 0.13 wt.%, 0.14 wt.%, 0.15 wt.%; the La content is more than or equal to 0.05 wt%, the matrix can be purified, the distribution condition of the Si element can be improved, the conductivity of the alloy can be improved, and stable Al is formed on a crystal boundary₁₁La₃The heat-resistant phase strengthens the crystal boundary, and is beneficial to obtaining better creep resistance and heat resistance; the La element can also enhance the interaction of Al and Cu elements, promote the precipitation of a Cu-containing heat-resistant phase, has a modification effect on the AlCuNi heat-resistant phase and optimizes the comprehensive performance of the alloy. When the La content is more than 0.15 wt.%, an excessive amount of the rare earth element and the aluminum matrix form a coarse intermetallic compound, which may in turn decrease the electrical conductivity of the alloy.

In the present invention, the content of Y is 0.005 to 0.020 wt.%, preferably 0.005 to 0.010 wt.%, specifically, such as 0.005 wt.%, 0.006 wt.%, 0.007 wt.%, 0.008 wt.%, 0.009 wt.%, 0.010 wt.%; the content of the Y element is more than or equal to 0.005 wt.%, and the desolventizing of the Zr element can be promoted to form Al₃The (Zr, Y) composite phase enhances the high-temperature coarsening resistance of the alloy, can also block the movement of dislocation and grain boundary at higher temperature, and improves the heat resistance and creep resistance of the alloy; when the Y content is more than 0.020 wt%, primary Al is generated when the alloy is solidified₃Y is generated, the content of Y element dissolved in the matrix is reduced, and Al is not easy to precipitate₃The (Zr, Y) composite particles, the conductivity and creep resistance of the alloy are affected.

The second purpose of the present invention is to overcome the defects of the prior art and provide a preparation method of an aluminum alloy conductor material with high conductivity, heat resistance and creep resistance, wherein the preparation method comprises the following steps: the method comprises the following steps of (1) preparing raw materials according to design components, smelting, carrying out rapid component analysis and component adjustment in front of a furnace, and then casting to obtain a bus, a guide rod, a casting blank or a continuous casting blank; the bus and the guide rod obtained by casting can be used as finished products, and the performance can be further improved by heat treatment; the casting blank can be extruded to obtain a bus bar and a guide rod; the continuous casting blank can be continuously rolled to obtain a wire blank, and then is subjected to heat treatment and drawing.

The smelting is carried out by remelting industrial pure aluminum ingot or using electrolytic aluminum stock solution as aluminum source, smelting at 730-770 deg.C, adding Al-Zr, Al-Cu, Al-Ni, Al-La and Al-Y intermediate alloy after aluminum smelting, refining, rapidly analyzing components in front of furnace, adjusting components according to designed material component ratio, removing slag and standing.

Casting according to the present invention includes, but is not limited to, general casting, semi-continuous casting, or continuous casting; the casting cooling speed is more than or equal to 20 ℃/s, desolventization is inhibited through rapid cooling, a driving force is provided for precipitating fine and dispersedly dispersed second phase particles through subsequent heat treatment, and meanwhile, the occurrence of unevenly distributed theta-Al in an as-cast structure is inhibited₂Coarse compounds such as Cu and AlCuNi prevent the coarse compounds from deteriorating the comprehensive performance of the material. FIG. 1 is a metallographic photograph of an as-cast structure of example 11 of the present invention, and it can be seen from FIG. 1 that the as-cast structure does not contain coarse primary phases under rapid cooling conditions. FIG. 2 is a scanning electron micrograph and an energy spectrum of a primary phase of an as-cast structure of example 11 of the present invention, wherein FIGS. 2(b) and 2(c) are energy spectra of a spherical primary phase and a primary phase at grain boundaries, respectively, indicated by arrows in FIG. 2(a), and it can be seen that the spherical AlCuNi phase weakens its cleavage effect on the matrix by deterioration; the primary phase on the grain boundary contains higher contents of La and Si elements, which shows that under the action of the La element, Si atoms are enriched to the grain boundary, the solid solution degree of the Si atoms is reduced, and the conductivity is improved.

The extrusion temperature is 380-420 ℃, the extrusion ratio lambda is more than or equal to 6, and the obtained extrusion rod has good surface quality and excellent structure and performance. The extrusion ratio lambda is 6-20 as a preferred process; more preferably 6 to 17.

The continuous rolling temperature is 470-520 ℃, the melting of low-melting-point phase is prevented, the final rolling temperature is lower than the recrystallization temperature so as to keep proper processing structure, and the final rolling is rapidly cooled after the final rolling so as to keep proper supersaturation degree.

The heat treatment of the invention comprises pre-aging and aging; the preaging temperature is 380-430 ℃, the time is 5-10h, the higher temperature provides sufficient phase change driving force to promote the nucleation of Zr-containing second phase particles and Al-Cu-Ni heat-resistant phase, and the Zr-containing second phase particles and the Al-Cu-Ni heat-resistant phase are subjected to high-temperature short-time preaging treatment to form uniformly distributed metastable phase; the aging temperature is 250-300 ℃, the time is 18-24h, the aging temperature is low, the second phase particles are not easy to coarsen, a highly dispersed second phase can be obtained, and the comprehensive performance of the aluminum alloy is improved.

In the invention, the drawing deformation is determined according to the strength of the product, and the deformation is preferably greater than or equal to 90%. As a further preferred embodiment, the average pass elongation coefficient is 1.25 to 1.50.

The high-conductivity heat-resistant creep-resistant aluminum alloy conductor material designed and prepared by the invention can be used as a conductive material. The conductive material includes, but is not limited to, wires, bus bars, guide bars, wires, cables.

The high-conductivity heat-resistant creep-resistant aluminum alloy conductor material designed and prepared by the invention is particularly suitable for preparing high-temperature-resistant wires and cables, overhead conductors and the like.

Principles and advantages

The invention provides a high-conductivity heat-resistant creep-resistant aluminum alloy conductor material and a preparation technology thereof, wherein the electric conductivity is more than 60.4 percent IACS at 20 ℃, the tensile strength exceeds 210MPa, the short-term (1h) heat-resistant temperature is 250 ℃, the long-term (400h) heat-resistant temperature is 210 ℃, and the steady-state creep rate under the stress conditions of 210 ℃ and 30MPa is less than or equal to 1.79 multiplied by 10^-7s^-1。

In the aspect of alloy components, a proper amount of Cu and Ni elements are added simultaneously to form a proper amount of aluminum-copper-nickel heat-resistant phase, the alloy strength and the recrystallization temperature are improved, Cu and Ni atoms are fully desolventized under the synergistic action of the elements, and the influence on the alloy conductivity is reduced. And a proper amount of La element is added to enhance the interaction between Al and Cu elements, promote the precipitation of a Cu-containing heat-resistant phase, further reduce the solid solution degree of the Cu element and optimize the comprehensive performance of the alloy. Al precipitated by compositely adding Zr and Y elements₃Y phase, may be Al₃Heterogeneous core of Zr aging precipitationThe alloy shows higher nucleation rate in the aging process, and the recrystallization temperature of the aluminum is effectively improved.

In the aspect of preparation process, the casting cooling speed is more than or equal to 20 ℃/s, the supersaturation degree of alloy elements is improved, and the occurrence of uneven distribution theta-Al in an as-cast structure is inhibited₂The damage of the coarse compounds such as Cu, AlCuNi and the like to the material performance is weakened, and the strength and the heat resistance of the alloy are improved. Through deformation, pre-aging and aging processes, the precipitation density of an aging phase is improved, so that the precipitation phase has better coarsening resistance, dislocation slippage and grain boundary migration are effectively inhibited, and the creep resistance and heat resistance of the aluminum alloy are improved. FIG. 3 is a metallographic photograph showing the structure of an alloy of example 11 of the present invention after drawing, in which a fine, dispersed second phase is distributed.

Drawings

FIG. 1 is a metallographic photograph of an as-cast structure according to example 11 of the present invention; .

FIG. 2 is a scanning electron micrograph of an as-cast structure and a primary phase spectrum thereof according to example 11 of the present invention;

FIG. 3 is a metallographic photograph taken after drawing in example 11 of the present invention;

FIG. 4 is a metallographic photograph showing an as-cast structure of comparative example 6 of the present invention;

FIG. 5 is a creep curve of examples 1, 8 and 2 according to the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following detailed description is given with reference to specific embodiments.

In the examples and comparative examples of the present invention, an industrial pure aluminum ingot was used as a raw material, Zr, Cu, Ni, La, and Y elements were added in the form of an intermediate alloy, the melting temperature was controlled at 750 ℃, the intermediate alloy was fully melted and then fully stirred, refined, and rapidly analyzed for components in front of the furnace, and the composition ratios shown in table 1 were adjusted according to the analysis results, wherein the content of impurity element Si was 0.05% or less, the total content of impurity elements Ti, V, Cr, and Mn was less than 0.01 wt.%, and the balance was Al.

TABLE 1 alloy element composition ratio table (wt%)

Continuously casting after chemical components are stable, wherein the casting cooling speed is 25 ℃/s, and continuously rolling the obtained casting blank to obtain an aluminum alloy round rod with the diameter of phi 9.5 mm; and (3) carrying out pre-aging treatment on the aluminum alloy round bar, wherein the pre-aging temperature is 400 ℃, the time is 6h, keeping the temperature for 18h for aging when the aluminum alloy round bar is cooled to 300 ℃, and finally carrying out cold drawing to obtain the phi 3mm aluminum alloy wire.

The tensile strength is tested according to the standard GB/T228.1-2010, the conductivity at 20 ℃ is tested according to GB/T12966-2008, the creep property of the test sample is tested according to the standard GB/T11546.1-2008, the experimental temperature is 210 ℃, the stress is 30MPa, and the test results are shown in Table 2.

TABLE 2 test results

As shown in Table 2, the high-conductivity, heat-resistant and creep-resistant aluminum alloy conductor material of the embodiment of the invention has the conductivity of more than 60.4% IACS at 20 ℃, the tensile strength of more than 210MPa, the short-term (1h) heat-resistant temperature of 250 ℃, the long-term (400h) heat-resistant temperature of 210 ℃, and the steady-state creep rate of less than or equal to 1.79 multiplied by 10 under the stress conditions of 210 ℃ and 30MPa^-7s^-1。

It can be seen from examples 1, 11, and 2 that the higher the content of Zr element, the better the heat resistance of the aluminum alloy conductor material, and the conductivity shows a tendency to decrease with the increase of Zr element content, but the sacrifice is not large, and the overall performance has a good combination property match. By combining example 11 with comparative examples 6 and 7, it can be seen that when the La element exceeds or falls below the range of the present invention, the conductivity of the alloy can not reach the index of the present invention, and the alloy can maintain a higher conductivity by adding a proper amount of La element. FIG. 4 is a metallographic photograph showing an as-cast structure of comparative example 6 of the present invention, from which it can be seen that dendrites of the as-cast structure are evident and a large amount of second-phase particles, mainly La-containing compounds, exist between the dendrites. Comparative examples 5 and 8 show that the conductivity is negatively affected when the Ni and Y element contents exceed the range of the present invention.

As can be seen from comparative examples 1, 2, 3, 4, 6 and 7, the Zr, Cu and La elements have obvious influence on the heat resistance and creep resistance of the alloy, when the content of one element is 0, the heat resistance and creep resistance of the alloy are obviously reduced, and when the content of one element exceeds the range of the invention, although the strength, the heat resistance and the creep resistance are all improved, the electric conductivity cannot reach the index of the invention. FIG. 5 is a creep curve chart of examples 1 and 8 and comparative example 2, and it can be seen from the graph that the creep curve is divided into three stages, wherein I is a deceleration creep stage, II is a steady-state creep stage, III is an acceleration creep stage, the steady-state creep stages of examples 1 and 8 are relatively gentle, and the steady-state creep rates are 1.79X 10^-7s^-1、1.45×10^-7s^-1The creep resistance is good; comparative example 2 has a Zr element content of 0, a steep steady-state creep stage and a steady-state creep rate of 2.27X 10^-7s^-1The creep resistance is poor.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.