EP4321644A1

EP4321644A1 - Aluminum alloy material, and aluminum alloy wire and preparation method therefor

Info

Publication number: EP4321644A1
Application number: EP21941638.5A
Authority: EP
Inventors: Yaojun MIAO; Feng Zhou; Xiaolin MIAO; Chunjian XU; Xiaohong HONG; Haibo Xu
Original assignee: Shanghai Zhongtian Aluminum Wire Co Ltd
Current assignee: Shanghai Zhongtian Aluminum Wire Co Ltd
Priority date: 2021-05-08
Filing date: 2021-10-21
Publication date: 2024-02-14
Also published as: WO2022237073A1; EP4321644A4; CN113234966A

Abstract

Disclosed are an aluminum alloy material, an aluminum alloy conductor and a preparation method thereof, which relates to the field of aluminum alloy. The aluminum alloy material includes the following components in percentage by mass: 0.1-0.25% of Fe, 0.01-0.05% of Si, 0.02-0.3% of Zr, 0.1-1% of M, 0.02-0.3% of Y, 0.01% or less of Mn, V, Ti and Cr, and Al in balance, where the mass ratio of Fe to Si is 2-8 and M is composed of La and Ce. By the selection of the specific components and the selection of the specific proportions, without significantly increasing the cost, the heat resistance and the mechanical property of the aluminum alloy material are effectively balanced and strengthened, and its conductivity is improved, so that the aluminum alloy material has excellent commercial application value.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure claims priority to Chinese Patent Application No. 202110503882.3, entitled with "ALUMINUM ALLOY MATERIAL, ALUMINUM ALLOY CONDUCTOR AND PREPARATION METHOD THEREOF", filed with China National Intellectual Property Administration on May 8, 2021 , which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of aluminum alloy, and in particular to an aluminum alloy material, an aluminum alloy conductor and a preparation method thereof.

BACKGROUND

Heat-resistant aluminum alloy conductor is a common conductor product for the capacity expansion and renovation of lines at present, and it may be used to replace commonly-used old steel-cored aluminum stranded wire in the existing line corridor and facility conditions, which is an effective solution for realizing the capacity expansion of lines and loss reduction of lines. However, due to the mutual restriction of the conductivity and heat resistance of aluminum alloy, it is extremely difficult to improve the conductivity of aluminum alloy conductor on the premise of ensuring the heat resistance.
The single-wire conductivity of common heat-resistant aluminum alloy conductors for engineering applications at home and abroad has been hovering at 60% IACS for a long time. The conductivities of aluminum alloys with different heat-resistant temperatures specified in the national standard GB/T 30551-2014 and the European standard BS EN 62004-2009 are shown in Table 1 below: Table 1 Conductivity of heat-resistant aluminum alloy

Type NRLH1 NRLH2 NRLH3 NRLH4

DC resistivity at 20°C, not more than /(Ω.mm²/m) (Conductivity, IACS) 0.028735 (60.0%) 0.031347 (55.0%) 0.028735 (60.0%) 0.029726 (58.0%)
It can be seen from the single-wire performance in Table 1 that, for whether domestic or foreign heat-resistant aluminum alloys, the highest conductivity of standard products for industrial applications is each 60% IACS. On the one hand, due to the general level of the industry, it is very difficult to increase the conductivity from 60% IACS to 61% IACS; on the other hand, in the technical solutions achieving 61% IACS conductivity, a series of expensive intermediate alloys are generally added, the treatment has a complex process, a high temperature and a long time, and the control conditions required in the actual production are complex and corresponding cost is high, so that it is difficult to realize the industrial production.

SUMMARY

The present disclosure provides an aluminum alloy material, including the following components in percentage by mass:

0.1-0.25% of Fe, 0.01-0.05% of Si, 0.02-0.3% of Zr, 0.1-1% of M, 0.02-0.3% of Y, 0.01% or less of Mn, V, Ti and Cr in total, and Al in balance;
where, a mass ratio of Fe to Si is 2 to 8, and the M is composed of La and Ce; and optionally, the M is composed of 25-45% of La and 55-75% of Ce in percentage by mass.

In some embodiments, the structures of the aluminum alloy material include an α-Al substrate and a Al-Zr-Y heat-resistant phase that is precipitated dispersedly; optionally, the heat-resistant phase has a radius of 8-20nm and a density of (1.8-4.2)*10¹⁸ N/m³.
In some embodiments, the aluminum alloy material is an aluminum alloy rod, an aluminum-alloy drawn single wire or an aluminum alloy conductor, and optionally, a conductivity of the aluminum alloy material is greater than 61% IACS.
The present disclosure further provides a preparation method of aluminum alloy conductor, including the following steps:

after obtaining an aluminum liquid according to a formula of an aluminum alloy conductor, adding an iron source, a silicon source, a zirconium source, a lanthanum source, a cerium source and a yttrium source into the aluminum liquid, and smelting to obtain an aluminum alloy melt;
purifying the aluminum-alloy melt, continuously casting and rolling, carrying out a heat treatment, and drawing to obtain an aluminum-alloy single wire, and then twisting to form an aluminum alloy conductor;
where, the formula includes the following components in percentage by mass:
- 0.1-0.25% of Fe, 0.01-0.05% of Si, 0.02-0.3% of Zr, 0.1-1% of M, 0.02-0.3% of Y, a total content of Mn, V, Ti and Cr being controlled to be less than or equal to 0.01%, and Al in balance;
- where, a mass ratio of Fe to Si is 2-8, and M is composed of La and Ce; optionally, M is composed of 25%-45% of La and 55%-75% of Ce by mass.

In some embodiments, the aluminum liquid is obtained by first obtaining an aluminum ingot and then melting the aluminum ingot, where the aluminum ingot has a purity of not less than 99.7%; or the aluminum liquid is obtained by directly using an electrolytic aluminum liquid.
In some embodiments, a temperature of the aluminum liquid is in a range of 720°C-750°C, 725°C-745°C, or 730°C-740°C.
In some embodiments, a temperature of the heat treatment is in a range of 160-250°C, 180-240°C or 190-210°C; and a duration of the heat treatment is in a range of 10-24h, 12-20h or 15-17h.
In some embodiments, a mass percentage of slag inclusion with a particle size of 10µm or more in the purified aluminum alloy melt is not higher than 3%.
In some embodiments, a content of hydrogen in the purified aluminum-alloy melt is less than or equal to 0.15ml/100g AL.
In some embodiments, the purifying step includes refining and multistage filtrating after refining.
Optionally, the refining is performed by means of adsorption purification or non-adsorption purification, where the adsorption purification includes using a powder-spraying refining agent or a degassing refining agent, and the non-adsorption purification includes vacuum treatment or ultrasonic treatment; and, the multistage filtrating is performed by a combination of a filter plate and an electromagnetic purification device.
In some embodiments, the purifying step further includes: before the multistage filtering step, keeping the aluminum alloy melt obtained after refining warm and resting for a preset time, and then stirring for on-line degassing.
In some embodiments, the purifying step further includes: after the refining step and before the on-line degassing step, sampling the aluminum alloy melt obtained after refining and determining the content of each component; if the content of each component is the same as that in the formula, proceeding to the next step; if the content of any component is different from that in the formula, returning to the smelting step and adjusting until the content of each component is the same as that in the formula, and then proceeding to the next step.
In some embodiments, in the step of continuous casting and rolling, the aluminum alloy melt has a temperature of 690°C-750°C, 690°C-710°C, 695°C-705°C or 700°C upon entering the casting machine;
optionally, in the step of continuous casting and rolling, an inlet rolling temperature is in a range of 450°C-550°C, 500°C-545°C or 530°C-540°C.
The present disclosure further provides an aluminum alloy conductor, which is prepared by the above preparation method.
Optionally, the stranded single wire of the aluminum alloy conductor has a conductivity of more than or equal to 61% IACS, a tensile strength of more than or equal to 151MPa, and a residual rate of strength after heating at 230°C for 1h of 90%.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in embodiments of the present disclosure more clearly, the following briefly introduces the accompanying drawings required to be used in the embodiments. It should be understood that, the following accompanying drawings illustrate merely some embodiments of the present disclosure and therefore should not be regarded as limiting the scope, and that persons of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative effort.
FIG. 1 is a photograph of the microstructures of the aluminum-alloy conductor after heat treatment provided in Example 1.

DESCRIPTION OF EMBODIMENTS

Implementations of the present disclosure will be described in detail below in conjunction with embodiments, but it should be understood by those skilled in the art that the following embodiments are merely illustrative of the present disclosure and should not be regarded as limiting the scope of the disclosure. If no specific condition is specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturers shall be followed. The reagents or instruments used, whose manufacturers are not indicated, are conventional products that may be purchased from the markets.
Since there is mutual restriction between the conductivity of aluminum alloy and the heat resistance and mechanical properties of aluminum alloy, it is extremely difficult to improve the conductivity of aluminum alloy on the premise of ensuring the mechanical properties and heat resistance. In view of this, the present disclosure provides an aluminum alloy material, an aluminum alloy conductor and a preparation method thereof. The following is described with respect to the exemplary aluminum alloy material, aluminum alloy conductor, and preparation method thereof in the present disclosure.
Firstly, the present disclosure provides an aluminum-alloy material, wherein the aluminum-alloy material herein may be an aluminum alloy rod, an aluminum-alloy drawn single wire or an aluminum alloy conductor (stranded single wires), and may also be an aluminum alloy plate or block, which is not specifically limited herein.
In some embodiments, the aluminum alloy material includes, in percentage by mass, the following components:
0.1-0.25% of Fe, 0.01-0.05% of Si, 0.02-0.3% of Zr, 0.1-1% of M, 0.02-0.3% of Y, 0.01% or less of Mn, V, Ti and Cr in total, and Al in balance. Where, the mass ratio of Fe to Si is 2-8, optionally, the mass ratio of Fe to Si is 2.5-7.5, 3-7, 4-6, or 4.5-5.5, and M is composed of La and Ce. Where, Mn, V, Ti, and Cr are main impurity elements that are inevitable.
Optionally, in percentage by mass, M is composed of 25%-45% of La and 55%-75% of Ce; for example, M is composed of 25% of La and 75% of Ce, or M is composed of 35% of La and 65% of Ce, or M is composed of 45% of La and 55% of Ce, etc.

Table 2 shows a comparison of the main components of a typical common heat-resistant alloy and the aluminum alloy material provided by the present disclosure.

Table 2 Composition comparison

Elements	Fe	Si	Zr	Y	M(La -Ce)	Total content of Mn, V, Ti and Cr	Fe/Si
Common heat-resistant	0.14-0.16	0.03-0.06	0.1-0.4 %	0.005-0.008	0.05	≤0.03%	4.4-6
The present disclosure	0.1%-0.25%	0.01%-0.05%	0.02%-0.3%	0.02%-0.3%	0.1% -1%	≤0.01%	2-8

It can be seen from Table 2 that, relative to the common heat-resistant alloy, the aluminum-alloy material provided by the present disclosure appropriately increases the content of composite rare earth elements (M and Y), reduces the content of zirconium, and simultaneously limits the mass ratio of Fe to Si to be 2-8. Through the selection of the specific components and the selection of the specific ratios, without significantly increasing costs, the heat resistance and the mechanical property of the aluminum alloy material are effectively balanced and strengthened, and the conductivity is improved, so that the aluminum alloy material has excellent commercial application value.
Particularly, based on that the composite rare earth elements (M and Y) have very low solid solubility in aluminum, during the solidification of the aluminum alloy, the rare earth element Y reacts with aluminum to generate an aluminum-rare earth element intermetallic compound with a high melting point, the solid solubility of which in the substrate is very low. The formed Al₃Y (D019 structure) may be used as a nucleation core for the age precipitation of Al₃Zr, which greatly reduces the interfacial energy required for the direct precipitation of Al₃Zr, and increases the precipitation rate of the heat-resistant phase. The amount of the particle of the heat-resistant phase is much more and the particle size is much smaller, and a large amount of dispersed precipitation of the second phase is finally formed. Furthermore, the Zr element inside the alloy substrate is further released to form an effective heat-resistant phase, which purifies the substrate and reduces the lattice distortion within the crystal, so that the electron passage capacity is rapidly improved, the dislocation is locked simultaneously and the dislocation movement is thus retarded, thereby realizing a perfect matching of strength and conductivity.
Compared with the common heat-resistant alloy, the aluminum alloy material provided by the present disclosure achieves reduced zirconium content and increased interaction of the rare earth elements, so that high residue of zirconium element in the crystal is avoided, the alloy substrate is purified, the conductivity is improved, and meanwhile, the precipitation amount of the heat-resistant phase is increased, the size of the precipitated phase is reduced, the strength is optimized, crystal grains are refined, and the heat treatment margin in the actual preparation process is improved, making it have better electrical conductivity.
Based on the specific components and ratios of the aluminum alloy material, the structures of the aluminum alloy material are an α-Al substrate and a Al-Zr-Y heat-resistant phase that is precipitated dispersedly, so that dislocation motion is locked, thereby effectively refining crystal grains, improving the conductive performance while strengthening the alloy, and providing good heat resistance. That is, based on the specific components and ratios of the aluminum alloy material, the aluminum alloy material has good conductivity and better heat resistance and mechanical properties, so that the aluminum alloy is particularly suitable for manufacturing a conductor.
Optionally, the heat-resistant phase has a radius of 8-20nm and a density of (1.8-4.2)*10¹⁸ N/m³. Through the fine and numerous heat-resistant phases, the conductivity of the aluminum alloy material is more than or equal to 61% IACS while maintaining the heat resistance.
Secondly, the present disclosure provides a preparation method of the aluminum alloy conductor, including the following steps.
S1. After obtaining an aluminum liquid according to a formula of an aluminum alloy conductor, adding an iron source, a silicon source, a zirconium source, a lanthanum source, a cerium source and an yttrium source into the aluminum liquid, and smelting to obtain an aluminum alloy melt.
Where, the aluminum liquid may be obtained by first obtaining an aluminum ingot and then melting the aluminum ingot. The aluminum ingot may be an aluminum ingot with a purity of not less than 99.7%, for purpose of avoiding the introduction of impurities. In addition, the aluminum liquid may also be obtained by directly using an electrolytic aluminum liquid.
The formula includes the following components in percentage by mass:
0.1-0.25% of Fe, 0.01-0.05% of Si, 0.02-0.3% of Zr, 0.1-1% of M, 0.02-0.3% of Y, Mn, V, Ti and Cr with a total content being controlled to be less than or equal to 0.01%, and Al in balance.
Where, a mass ratio of Fe to Si is 2-8, optionally a mass ratio of Fe to Si is 2.5-7.5, 3-7, 4-6 or 4.5-5.5, and M is composed of La and Ce. The iron source, silicon source, zirconium source, lanthanum source and cerium source may be used as elementary substances or as alloys, and if the corresponding component has no elementary substance, an alloy containing at least two of the above components may be directly used. Where, Mn, V, Ti, and Cr are main impurity elements that are inevitably introduced by alloys of the above components, which are not limited herein.
Optionally, the temperature of the aluminum liquid is in a range of 720°C-750°C, for example, the temperature of the aluminum liquid is 720°C, 725°C, 730°C, 735°C, 740°C, 745°C or 750°C.
Where, step S1 is performed in a furnace, and the furnace may be a holding furnace or a resistance furnace.
S2. Purifying the aluminum alloy melt, performing continuous casting and rolling, performing a heat treatment, drawing to obtain an aluminum alloy single wire, and then twisting to form an aluminum alloy conductor.
The hydrogen content and slag inclusions in the aluminum alloy melt have a great influence on the quality of the final aluminum alloy product. Therefore, optionally, the mass percentage of slag inclusions with a particle size of 10µm or more in the purified aluminum alloy melt is not higher than 3%. Through the above limitation, the distortion in the alloy crystal may be effectively reduced, and then the conductivity may be effectively improved.
Optionally, a content of hydrogen in the aluminum alloy melt obtained after purification is less than or equal to 0.15ml/100g AL. Through the limitation, the formation of air holes and the like during the solidification of subsequent cast ingots is effectively prevented, the problems of easiness for fracture and the like caused by hydrogen are simultaneously avoided, the tensile strength is improved, and the specific morphology during casting is adjusted.
Where, in order to obtain the above purification effect, in an optional purification solution shown in the present disclosure:
the step of purification includes: refining, and performing multistage filtrating through a filter plate and an electromagnetic purification device after refining.
The refining may be performed by adsorption purification or non-adsorption purification. In some embodiments, the adsorption purification mode may include a powder-spraying refining agent or a degassing refining agent for deslagging and degassing, and the non-adsorption purification mode may include vacuum treatment or ultrasonic treatment, which can also achieve the effects for deslagging and degassing.
The inventor finds that only the above refining step cannot allow the content of slag inclusions with a particle size of 10µm or more to be not less than 3%. Therefore, in some embodiments, the purification steps further include multi-stage filtrating to remove non-metallic impurities in the aluminum alloy melt, so as to achieve the purpose of purifying the aluminum alloy melt, thereby improving the structural performance of the product.
The electromagnetic purification device may effectively purify non-metallic impurities and improve the structural performance of the product, and has simple operation process. The filter plate includes but is not limited to a filter plate of ceramic foam, and may also be a tubular filter plate, a bed-type filter plate and the like, which also achieves the effect for filtering and deslagging, and is not specifically limited herein.
Optionally, the filter plate and the electromagnetic purification device are disposed outside a furnace, and in particular, disposed in a trough between the furnace and a device employed in the continuous casting step.
In some embodiments, before the multistage filtering step, the purifying step further includes: keeping the aluminum alloy melt obtained after refining warm and resting for a preset time, and then stirring for online degassing. The slags may be settled by resting for a preset time, and the gas is fully overflowed by stirring after being settled, so that the gas may be further effectively degassed, the degassing effect is ensured, and the online degassing process avoids further introduction of impurities at the same time.
The online degassing is carried out by an online degassing device, where, the reaction chamber of the online degassing device is provided with one or more rotary nozzles, the rotary nozzles may rotate unidirectionally or bidirectionally, and meanwhile, the rotary nozzles may be made of graphite or other materials. The online degassing may be any online degasifying device outside the furnace as long as it can achieve the purpose of online degasification.
It should be noted that, in the actual production and preparation process, due to the error of the raw materials themselves, there may be a certain error between the formula ratio of actually-melted aluminum alloy melt and the actual formula ratio. Therefore, in some embodiments, after the refining step and before the online degassing step, the purifying step further includes sampling the aluminum alloy melt and determining the content of each component; and proceeding to the next step if the content of each component is the same as that in the formula, or if the content of any component is different from that in the formula, returning to the smelting step of S1 and adjusting until the content of each component is the same as that in the formula, and then proceeding to the next step.
Optionally, in the continuous casting and rolling step of S2, the temperature of the aluminum alloy melt when entering a crystallizing wheel of a continuous casting machine is in a range of 690°C-750°C, for example, 690°C-710°C; for example, the temperature when entering the casting machine is 690°C, 695°C, 700°C, 705°C or 710°C, etc.
Optionally, in the continuous casting and rolling step of S2, an inlet rolling temperature is 450°C-550°C, for example, the inlet rolling temperature is 450°C, 500°C, 530°C, 540°C, 545°C or 550°C, etc. The aluminum alloy rod is obtained by hot rolling.
Optionally, the temperature of the heat treatment in S2 is 160-250°C, for example, the temperature of the heat treatment is 160°C, 165°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C, etc. The heat treatment is performed for 10-24h, for example, the heat treatment is performed for 10h, 12h, 15h, 17h, 18h, 20h or 24h. The aluminum alloy rod is pretreated by the above heat treatment mode, so that the precipitation of the heat-resistant phase may be strengthened, the distortion within the crystal of the aluminum alloy may be further reduced, the mechanical and electrical properties of the obtained aluminum alloy rod may be improved, and the conductivity of the aluminum alloy rod may be greater than 61% IACS.
That is, the aluminum alloy material provided above in the present disclosure may be an aluminum alloy rod obtained after the above heat treatment, which has a conductivity of greater than 61% IACS.
The above preparation method is simple. Through cooperation of the preparation method with the formula of the aluminum alloy conductor, the heat resistance and the conductivity of the aluminum alloy conductor may be effectively enhanced, so that the conductivity of the stranded single wire of the aluminum alloy conductor may reach 61% IACS or more. Meanwhile, the preparation method is simple in production control and low in cost increase, and can greatly reduce the line loss, thereby having a better commercial value.
Finally, the present disclosure further provides an aluminum alloy conductor, which is prepared by the above preparation method provided by the present disclosure. The aluminum alloy conductor is obtained after the aluminum alloy rod is drawn and twisted, where a stranded single wire of the aluminum alloy conductor prepared by the above preparation method has a conductivity of more than or equal to 61% IACS, a tensile strength of more than or equal to 151MPa, and a residual rate of strength after heating at 230°C for 1h of 90%.
The aluminum alloy material, the aluminum alloy conductor, and the preparation method thereof in the present disclosure are further described in detail below with reference to Examples.

Example 1

An aluminum alloy conductor was prepared by the following preparation method.

(1) According to the parameters of Example 1 listed in Table 3, raw materials were prepared as an intermediate alloys for iron source, silicon source, zirconium source, lanthanum source, cerium source and yttrium source and an aluminum ingot with a purity of 99.7% was also prepared.
(2) The aluminum ingot with the purity of 99.7% was smelted in a holding furnace, followed by accurately feeding the rest raw materials for smelting to ensure that the aluminum alloy liquid obtained by smelting includes the following components in percentage by mass: 0.166% of Fe, 0.023% of Si, 0.047% of Zr, 0.112% of M and 0.044% of Y, 0.01% or less of Mn, V, Ti and Cr in total, and the balance of Al, and the mass ratio of Fe to Si is 7.2.
(3) A powder-spraying refining agent was employed to remove slags and gas in the holding furnace, for performing purification inside the furnace.
(4) The aluminum alloy liquid in the holding furnace was sampled for verifying that the content of each element is qualified.
(5) The aluminum alloy liquid was kept standing in the holding furnace for 30 min.
(6) The aluminum alloy liquid was stirred electromagnetically in the holding furnace to remove gas again, and the content of hydrogen was measured on line to be less than or equal to 0.15ml/100g AL.
(7) Multistage filtering was performed using a 30-mesh foam-ceramic filter plate and an electromagnetic purification device in a trough to remove non-metallic impurities, so that the content (in percentage by mass) of slag inclusions with a particle size of 10µm or more is not more than 3% in the aluminum alloy liquid.
(8) The aluminum alloy liquid prepared in the step (7) was fed into a continuous casting and rolling production line, enabling the aluminum alloy liquid to flow to a casting ladle through the trough for automatic casting, the temperature of lower casting (namely the temperature when entering a casting machine) being 720°C, to obtain a cast ingot, and the cast ingot was cooled to be about 500°C and then fed into a continuous rolling machine for rolling to obtain a rod with a diameter of 9.5mm.
(9) A heat treatment was performed for the rod in a box-type aging furnace at 240°C for 16 hours.
(10) The rod obtained in the step (9) was drawn by using a double-head wire drawing machine with 11 dies to form single wires with the specification of 4.22mm in diameter, and the single wires were twisted to form an aluminum alloy conductor.

FIG. 1 is a photograph of microstructures of the aluminum alloy conductor after heat treatment (step (9)) provided in Example 1. It can be seen that the structures of the aluminum alloy material are an α-Al substrate (gray part in the figure) and a dispersively-precipitated Al-Zr-Y heat-resistant phase (black dots). Where, in this example, the radius of the heat-resistant phase is 10.7nm, the density of the heat-resistant phase is 2.94*10¹⁸ N/m³, and the content of Zr in the substrate is 0.003%.

Examples 2 to 5

Examples 2-5 were prepared in a manner similar to Example 1, except for the parameters as shown in Table 3. In Examples 1 to 5, M is composed of 35% of La and 65% of Ce (in percentage by mass).

Table 3 Parameters for Examples 1-5

	Si (%)	Fe(%)	Fe/Si	Zr(%)	M(%)	Y(%)	Heat treatment
	Si (%)	Fe(%)	Fe/Si	Zr(%)	M(%)	Y(%)	Temperatur e (°C)	Time (h)
Example 1	0.023	0.166	7.2	0.047	0.112	0.044	240	16
Example 2	0.041	0.203	4.9	0.033	0.138	0.056	205	20
Example 3	0.033	0.182	5.5	0.051	0.245	0.032	180	24
Example 4	0.028	0.14	5	0.042	0.452	0.031	195	23
Example 5	0.031	0.201	6.5	0.039	0.251	0.024	195	24

The structures of the conductors of Examples 1-5 after heat treatment were similar to those of Example 1, which each included an α-Al substrate and a Al-Zr-Y heat-resistant phase that was precipitated dispersedly.
Conductivity and tensile strength tests were performed on the rods and the stranded single wires of the aluminum alloy conductor obtained in Examples 1 to 5 according to GB/T 30551 2014 . The residual rate of strength refers to the ratio (residual rate) of the strength of a single wire after heating at 230°C for 1h to its initial measurement value at room temperature, so as to characterize its heat resistance.

The measurement results are shown in Table 4.

Table 4 Measurement results

	Conductivity of rod (IACS)	Stranded single wire of the aluminum alloy conductor
	Conductivity of rod (IACS)	Conductivity (IACS)	Tensile strength (MPa)	Strength retention rate (230°C, 1h)
Example 1	61.83%	61.52%	164	93%
Example 2	61.79%	61.31%	158	92%
Example 3	61.54%	61.38%	167	92.4%
Example 4	61.97%	61.92%	159	94.1%
Example 5	61.99%	61.93%	154	94.5%

According to the measurement results in Table 4, it can be seen that the conductivities of the rod and the stranded single wire of the conductor in the present disclosure can reach 61% IACS and above.
For the conductors prepared in Examples 1 to 5, the heat resistance test showed that the residual rate of strength after heating at 230°C for 1h was 92% or more.

Example 6

The preparation method of Example 6 was similar to that of Example 1, except only that the aluminum alloy conductor included the following components: 0.166% of Fe, 0.023% of Si, 0.047% of Zr, 0.112% of M and 0.044% of Y, 0.1% or less of Mn, V, Ti and Cr in total, and Al in balance; where the mass ratio of Fe to Si was 7.2. M was composed of 45% of La and 55% of Ce in percentage by mass.
The conductivity of rod was 61.7% IACS, the conductivity of conductor was 61.3% IACS, the tensile strength of the single wire of conductor was 158MPa, and the residual rate of strength of the single wire of conductor after heating at 230°C for 1h was greater than 92%.

Comparative example 1

A common heat-resistant alloy as shown in Table 2 was used to prepare a conductor by the preparation method of Example 1 of the present disclosure.
The conductivity of the stranded single wire was 60%, and its heat-resistant phase was Al-Zr, the radius of the heat-resistant phase was 22.38nm, the density of the heat-resistance phase was 1.49*10¹⁸ N/m³, and the content of Zr in the substrate was 0.065%.

Comparative example 2

Compared with Example 1 of the present disclosure, the only difference was that the rod to be used was directly obtained without undergoing heat treatment.
Where, the conductivity of the rod was 60.7% IACS, the conductivity of the conductor was 59.8% IACS, and the tensile strength of the conductor was 164MPa.

Comparative example 3

Compared with Example 1 of the present disclosure, the only difference was that the aluminum alloy conductor included the following components in percentage by mass: 0.166% of Fe, 0.023% of Si, 0.047% of Zr, 1.1% of M and 0.044% of Y, 0.1% or less of Mn, V, Ti and Cr in total, and Al in the balance; where the mass ratio of Fe to Si was 7.2. M was composed of 35% La and 65% Ce in percentage by mass.
The conductivity of the conductor was 59.3% IACS, and the tensile strength of the conductor was 145MPa.

Comparative example 4

Compared with Example 1 of the present disclosure, the only difference was that the aluminum alloy conductor included the following components: 0.23% of Fe, 0.023% of Si, 0.047% of Zr, 0.112% of M, 0.044% of Y, 0.1% or less of Mn, V, Ti and Cr, and Al in balance; where the mass ratio of Fe to Si was 10, and M was composed of 35% La and 65% Ce in percentage by mass.
The conductivity of the conductor was 58.7% IACS, and the tensile strength of the conductor was 166MPa.

Comparative example 5

Compared with Example 1 of the present disclosure, the only difference was that steps (6) and (7) were absent in this comparative example.
The conductivity of the conductor was 59.6% IACS, and the tensile strength of the conductor was 142MPa.
To sum up, the aluminum alloy material provided by the embodiments of the present disclosure effectively improves the conductivity of the aluminum alloy material through a specific component ratio on the premise of ensuring the mechanical properties and heat resistance of the aluminum alloy material. The preparation method of the aluminum alloy conductor is controllable in operation; and with the specific component proportion and the above specific preparation method, the conductivity of the aluminum alloy conductor is further effectively improved on the premise of ensuring the mechanical property and the heat resistance of the aluminum alloy conductor, so that the conductivity of aluminum alloy conductor is more than or equal to 61% IACS.
The foregoing is merely exemplary embodiment of the present disclosure and not intended to limit the present disclosure. It is apparent for those skilled in the art that, various modifications and variations can be made on the present disclosure. Any modification, equivalent substitution, improvement, etc. within the spirit and principle of the present disclosure shall be included in the scope of protection of the present disclosure.

Industrial applicability

According to the aluminum alloy material provided by the present disclosure, through the selection of specific components and the selection of specific proportions, without not significantly increasing the cost, the heat resistance and the mechanical property of the aluminum alloy material are effectively balanced and strengthened, and its conductivity is improved, so that the aluminum alloy material has excellent commercial application value. The preparation method is simple in production control and low in cost increase, and can greatly reduce the line loss, so that the prepared aluminum alloy conductor has a great commercial application prospect.

Claims

An aluminum alloy material, comprising the following components in percentage by mass:
0.1-0.25% of Fe, 0.01-0.05% of Si, 0.02-0.3% of Zr, 0.1-1% of M, 0.02-0.3% of Y, 0.01% or less of Mn, V, Ti and Cr in total, and Al in balance;

wherein a mass ratio of Fe to Si is 2 to 8, and the M is composed of La and Ce.
The aluminum alloy material according to claim 1, wherein the structures of the aluminum alloy material are an α-Al substrate and a Al-Zr-Y heat-resistant phase that is precipitated dispersedly;
optionally, the heat-resistant phase has a radius of 8-20nm and a density of (1.8-4.2)*10¹⁸ N/m³.
The aluminum alloy material according to claim 1 or 2, wherein the M is composed of 25-45% of La and 55-75% of Ce in percentage by mass.
The aluminum alloy material according to any one of claims 1-3, wherein the aluminum alloy material is an aluminum-alloy rod, an aluminum-alloy drawn single wire or an aluminum alloy conductor and optionally, a conductivity of the aluminum alloy material is greater than 61% IACS.
A preparation method of an aluminum alloy conductor, comprising the following steps:
after obtaining an aluminum liquid according to a formula of the aluminum alloy conductor, adding an iron source, a silicon source, a zirconium source, a lanthanum source, a cerium source and a yttrium source into the aluminum liquid, and smelting to obtain an aluminum alloy melt;

purifying the aluminum alloy melt, carrying out continuous casting and rolling, performing a heat treatment, and drawing to obtain an aluminum alloy single wire, and then twisting to form an aluminum alloy conductor;

wherein the formula comprises the following components in percentage by mass:

0.1-0.25% of Fe, 0.01-0.05% of Si, 0.02-0.3% of Zr, 0.1-1% of M, 0.02-0.3% of Y, 0.01% or less of Mn, V, Ti and Cr in total, and Al in balance;

wherein a mass ratio of Fe to Si is 2-8, and the M is composed of La and Ce;

optionally, the M is composed of 25%-45% of La and 55%-75% of Ce in percentage by mass.
The preparation method according to claim 5, wherein the aluminum liquid is obtained by first obtaining an aluminum ingot and then melting the aluminum ingot, wherein the aluminum ingot has a purity of not less than 99.7%, or the aluminum liquid is obtained by directly using an electrolytic aluminum liquid.
The preparation method according to claim 5 or 6, wherein a temperature of the aluminum liquid is in a range of 720°C-750°C, 725°C-745°C, or 730°C-740°C.
The preparation method according to any one of claims 5-7, wherein a temperature of the heat treatment is in a range of 160-250°C, 180-240°C or 190-210°C; and a duration of the heat treatment is in a range of 10-24h, 12-20h or 15-17h.
The preparation method according to any one of claims 5-8, wherein a mass percentage of slag inclusion with a particle size of 10µm or more is not higher than 3% in the purified aluminum alloy melt.
The preparation method according to any one of claims 5-9, wherein a content of hydrogen in the purified aluminum alloy melt is less than or equal to 0.15ml/100g AL.
The preparation method according to any one of claims 5-10, wherein the purifying step comprises refining and multistage filtrating after refining.
The preparation method according to claim 11, wherein the refining is performed by means of adsorption purification or non-adsorption purification, the adsorption purification comprises using a powder-spraying refining agent or a degassing refining agent, and the non-adsorption purification comprises vacuum treatment or ultrasonic treatment; and, the multistage filtrating is performed by a combination of a filter plate and an electromagnetic purification device.
The preparation method according to claim 11 or 12, wherein the purifying step further comprises: before the multistage filtering step, keeping the aluminum alloy melt obtained after refining warm and resting for a preset time, and then stirring for on-line degassing.
The preparation method according to claim 13, wherein the purifying step further comprises: after the refining step and before the on-line degassing step, sampling the aluminum-alloy melt obtained after refining and determining a content of each component; if the content of each component is the same as that in a formula, proceeding to the next step; if the content of any component is different from that in the formula, returning to the smelting step and adjusting until the content of each component is the same as that in the formula, and then proceeding to the next step.
The preparation method according to any one of claims 5-14, wherein in the step of continuous casting and rolling, the aluminum-alloy melt has a temperature of 690°C-750°C, 690°C-710°C, 695°C-705°C or 700°C upon entering the casting machine;
optionally, in the step of continuous casting and rolling, an inlet rolling temperature is in a range of 450°C-550°C, 500°C-545°C or 530°C-540°C.
An aluminum alloy conductor, prepared by the preparation method according to any one of claims 5-15.
The aluminum alloy conductor according to claim 16, wherein the stranded single wire of the aluminum alloy conductor has a conductivity of more than or equal to 61% IACS, a tensile strength of more than or equal to 151MPa, and a residual rate of strength after heating at 230°C for 1h of 90%.