A novel cubically oriented high-conductivity, high-thermal-conductivity Al-Mg-Si-Fe-Y aluminum alloy strip for electronic circuit connection and a preparation process thereof

Abstract

The application relates to the technical field of aluminum alloy materials, in particular to a novel Al-Mg-Si-Fe-Y aluminum alloy strip for electronic circuit connection with high electric conductivity and high thermal conductivity and a preparation process thereof, which contains the following components in percentage by mass: 0.9-1.5 wt.% of Mg, 0.25-0.85 wt.% of Si, 0.25-0.85 wt.% of Fe, 0.1-0.3 wt.% of Cu, 0.05-0.3 wt.% of Y, and the balance of Al and inevitable impurities. The alloy component is simplified, the preparation process is optimized, the aluminum alloy strip prepared through the cooperation of various steps is mainly characterized by a nano beta '' (Mg2Si) phase and a high cubic orientation grain matrix, the electric conductivity and the thermal conductivity are greatly improved, and the total processing time is effectively saved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy materials technology, and in particular to a novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting electronic circuits with high electrical and thermal conductivity, and its preparation process. Background Technology

[0002] 6201 Al-Mg-Si alloy (standard composition: Mg 0.6-0.9%, Si 0.5-0.9%, Fe 0.5%, Cu 0.1%, Mn 0.03-0.05%) features moderate strength, corrosion resistance, weldability, easy forming, and low cost, making it widely used in power transmission, electronic communication connectors, and thermal management devices. The electrical conductivity of standard 6201 aluminum alloy sheet is 48-51% IACS (T6); its thermal conductivity ranges from 160-170 W / (mK) (T6).

[0003] With the rapid development and deployment of 5G / 6G communication technologies in China, high-frequency, high-power, and high-density electronic power devices, such as IGBT chips, are being used extensively. This has led to increasingly higher heat flux density and heat dissipation in circuits. Consequently, the conductivity and thermal conductivity of traditional circuits are becoming insufficient, which can easily cause degradation or even premature failure of core electronic components such as chips. Therefore, while emphasizing high conductivity, it is particularly urgent to further design and develop novel Al-Mg-Si aluminum alloys that combine higher conductivity and thermal conductivity.

[0004] Mn is a commonly used trace element in aluminum alloys. It can modify the morphology of Fe-containing impurity phases, thereby reducing their damage to the aluminum matrix and significantly contributing to the strength of aluminum alloys. Furthermore, Mn can increase the recrystallization temperature. However, Mn is also the element that most severely affects the electrical and thermal conductivity of aluminum alloys. On the one hand, Mn readily forms coarse, blocky Al6(Fe,Mn,Si) second phase as well as acicular Al6Mn and T phase (Al2O3). 20Cu2Mn3, while strengthening the matrix, also increases electron scattering, thereby weakening the electrical and thermal conductivity of aluminum alloys. On the other hand, the increased Mn content leads to a weakening or even deorientation of the aluminum alloy's texture. This is detrimental to cubic orientation / texture (Cube{110}), which promotes electrical and thermal conductivity. <001> The formation of Mg2Si phase. Y is a rare metallic element. Studies have shown that in aluminum alloys, Y can purify the aluminum alloy melt, refine the grain structure, and coat the spheroidized second phase, reducing heat dissipation from electron transport in the second phase. Furthermore, Y can form a dispersed spheroidal Al3Y phase, which is beneficial for the formation of cubic oriented grains. Recent research indicates that a strong cubic orientation (texture) has a low dislocation density, effectively reducing the impact on heat dissipation and electron heat transfer. Si contributes to the formation of the Mg2Si phase, enhancing the Al-Mg-Si strength of the alloy and improving its thermal stability.

[0005] Homogenization heat treatment effectively eliminates compositional segregation and dendrites caused by non-equilibrium solidification in ingots, thus becoming a key front-end process step in the preparation of high-performance aluminum alloy materials. Traditional homogenization heat treatment typically employs high-temperature, long-duration, single-stage annealing near the solid solution point, a simplistic process with high energy consumption. Two-stage homogenization heat treatment is a novel, efficient, and energy-saving heat treatment method that has emerged in recent years. Unfortunately, domestic enterprises have not yet given it sufficient attention.

[0006] Therefore, we conducted in-depth research on how to solve the problems existing in the current technology. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for high electrical and thermal conductivity electronic circuit connections and its preparation process. This invention simplifies the alloy composition, optimizes the preparation process, and produces aluminum alloy strips with nano-β-coated alloys through the synergistic operation of each step. (Mg 2 Si) The main features are a phase and a highly cubic orientation grain matrix, which greatly improves electrical conductivity and thermal conductivity, and effectively saves the total processing time.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting high-conductivity and high-thermal-conductivity electronic circuits comprises, by mass percentage: 0.9–1.5 wt.% Mg, 0.25–0.85 wt.% Si, 0.25–0.85 wt.% Fe, 0.1–0.3 wt.% Cu, 0.05–0.3 wt.% Y, with the balance being Al and unavoidable impurities.

[0010] A novel fabrication process for Al-Mg-Si-Fe-Y aluminum alloy strips with high electrical and thermal conductivity for cubic orientation electronic circuit connections includes the following steps:

[0011] S1, Raw material pretreatment;

[0012] S2, first put 99.5wt% industrial pure aluminum into a pit-type resistance furnace and graphite crucible for smelting at a smelting temperature of 730-780℃, while applying a low-frequency electromagnetic field. After all the pure Al has melted, add sufficient amounts of dried Al-Fe, Al-Y, Al-Mg, and Al-Si master alloys in sequence, and sprinkle a covering agent on top of the melt for protection.

[0013] S3. After confirming with a graphite rod that all the smelting raw materials in step S2 have melted, degas the melt.

[0014] S4, the melt after degassing in step S3 is cast to obtain a thin strip;

[0015] S5, Perform multi-level gradient homogenization heat treatment on the thin strip obtained in step S4.

[0016] S6. The strip that has been homogenized in step S5 is preheated to 480-500℃ and held for 2 hours. Then, it is first subjected to asynchronous hot rolling, then pre-aging treatment for 1 hour, and finally warm rolling to obtain hot-rolled strip.

[0017] S7, the hot-rolled thin strip obtained in step S6 is subjected to deep cold rolling and T6 aging treatment;

[0018] S8. Perform surface strengthening treatment on the thin strip after step S7.

[0019] Preferably, the specific operation of the raw material pretreatment in step S1 is as follows: accurately weigh according to the formula ratio, use Al-Mg, Al-Si, Al-Fe, Al-Y master alloys to prepare raw materials, sandblast the billet of the master alloy to remove oxide scale, perform ultrasonic cleaning in pure water at 55-65℃ and 20kHz for 15 minutes, and then vacuum low temperature drying at 75-85℃ for 2 hours.

[0020] In the above operations, sandblasting removes surface oxide scale, ultrasonic cleaning removes micron-sized dust and oil, and low-temperature vacuum drying prevents secondary oxidation and moisture residue. This step replaces chemical pickling with physical cleaning to reduce the risk of impurity introduction (single impurity ≤0.05wt.%), while sandblasting + ultrasonic cleaning ensures the uniformity of the composition in subsequent melting, with composition fluctuation <±0.1%.

[0021] Preferably, in step S2, the low-frequency electromagnetic field has a frequency of 5-20Hz, a magnetic field strength of 0.1-0.5T, and a direction perpendicular to the direction of melt convection.

[0022] A low-frequency electromagnetic generator (frequency range 0.1-50Hz) can be combined with a ring-shaped electromagnetic coil. The coil is wound around the outside of the pit-type resistance furnace, with the magnetic field direction perpendicular to the natural convection direction of the melt. The magnetic field strength is achieved by adjusting the coil current density. The electromagnetic field suppresses large-scale melt flow through the Lorentz force, forcing the melt to form micro-area eddies, eliminating the "dead zone" segregation of traditional smelting, and eliminating the need for subsequent hexachloroethane refining, thus reducing the emission of toxic gases (such as Cl2). Specifically, setting the magnetic field frequency <20Hz can suppress macroscopic melt convection and reduce dendrite segregation rate, while a magnetic field strength of 0.1-0.5T can refine the primary Al-Fe-Si-Y phase to 50-200nm. Sufficient amounts of dried Al-Fe, Al-Y, Al-Mg, and Al-Si master alloys are added sequentially. The high-melting-point master alloys Al-Fe and Al-Y are added first, and the melting is accelerated by an electromagnetic field, which shortens the melting time. Al-Mg and Al-Si are added later, and the magnetic field suppresses the volatilization of Mg, so that the volatilization loss rate is less than 0.5%, while also causing Si element to segregate.

[0023] Preferably, the specific operation of degassing in step S3 is as follows: a vacuum rotary degasser is set with a vacuum degree of <1kPa, a rotor speed of 500rpm, and a blade tilt angle of 45°. The melt is injected into the degassing chamber and degassing is continued for 10-15 minutes until the bubbles are broken down to a diameter of <0.5mm. After standing for 20 minutes, the slag is removed, and the hydrogen content of the melt is controlled to <0.1mL / 100g.

[0024] The traditional hexachloroethane (C2Cl6) degassing process has been completely replaced, avoiding Cl... - Residue and environmental pollution are reduced by vacuum rotation breaking up bubbles, which improves efficiency, reduces porosity defects, effectively controls hydrogen content, and is more environmentally friendly.

[0025] Preferably, the specific operation of pouring in step S4 is as follows: the molten metal is poured into a single-roll thin strip continuous casting machine, poured onto the roll surface through a nozzle, and the cooling rate is controlled at 10. 3 -10 6 K / s, directly producing thin strips with a thickness of 0.5 to 1 mm; among them, the copper roll diameter of the single roll thin strip continuous casting machine is 800 mm, and the roll speed is 20 to 30 m / s.

[0026] This step ensures that the precipitated phase size in the casting strip is ≤200nm (compared to >1μm in traditional ingots), and a roll speed >20m / s can suppress the coarsening of the Al-Fe-Si-Y phase. A cooling rate >10 3 K / s increases the supersaturation solubility of solute atoms; controls the nano-precipitated phase, rapidly solidifies to suppress coarse and brittle phases, improves the plasticity of subsequent processing, and enables direct forming of thin strips, eliminating the traditional hot rolling process and effectively reducing energy consumption.

[0027] Preferably, the multi-level gradient homogenization heat treatment in step S5 specifically includes the following steps:

[0028] S51, First stage: 360℃ heat preservation for 2 hours;

[0029] S52, Second Stage: 520℃ heat preservation for 8 hours;

[0030] S53, third stage: heat preservation at 580℃ for 6 hours, followed by furnace cooling.

[0031] In the above operation, the first stage, holding at 360℃ for 2 hours, can eliminate dendritic segregation (the segregation index decreases from 1.5 to 0.3); the second stage, holding at 520℃ for 8 hours, can melt the low-melting-point eutectic phase (such as Al-Mg2Si, melting point ≈550℃); the third stage, holding at 580℃ for 6 hours, promotes the spheroidization of the Al-Fe-Si-Y phase, with sphericity >0.8 and size <500nm. The spheroidization of the Al-Fe-Si-Y phase can reduce stress concentration, improve conductivity, and work synergistically with subsequent rolling deformation to avoid crack initiation.

[0032] Preferably, the asynchronous hot rolling conditions in step S6 are: upper and lower roll speed ratio 1:1.2, until the total deformation reaches 80-90%; the warm rolling temperature is 200-250℃, and the deformation is 60-80%.

[0033] Preheating ensures a temperature gradient of less than 10℃ / mm on the sheet; asynchronous hot rolling with an upper and lower roll speed ratio of 1:1.2 induces shear strain, increases the proportion of cubic orientation, and accumulates a dislocation density of 101. 4 m - 2; Pre-aging treatment forms GP regions (size 2-5nm) to suppress dynamic recovery; final warm rolling temperature >200℃ suppresses twin formation, improves plasticity isotropy, and refines grain size to 2-5μm.

[0034] Preferably, the cryogenic rolling and T6 heat treatment in step S7 specifically include the following steps:

[0035] S71, Liquid nitrogen cryogenic treatment: The warm-rolled aluminum alloy strip is immersed in liquid nitrogen at -196℃ for 10 minutes.

[0036] S72, cryogenic rolling: The strip after cryogenic treatment in step S71 is cold rolled at room temperature with a deformation of 50%.

[0037] S73, solution treatment: heat the plate to 540℃±5℃ and hold for 1 hour to allow the β” phase to fully melt into the aluminum matrix; water quench at 20~30℃ with a cooling rate >200℃ / s to form a supersaturated solid solution;

[0038] S74: Artificial aging: Holding at 175℃±2℃ for 8 hours promotes the precipitation of nano-scale β” phase; after aging, the β” phase size is ≤50nm, and the number density reaches 10. 22 m -3 The strength is significantly improved, and it is air-cooled to room temperature.

[0039] The warm-rolled aluminum alloy strip is immersed in liquid nitrogen for 10 minutes to suppress dislocation recovery and increase lattice distortion energy. The dislocation movement is frozen in an ultra-low temperature environment, preserving the high-density dislocations formed during rolling and providing a strengthening foundation for subsequent cold rolling. The cryogenically treated strip is then cold-rolled at room temperature at a speed ≤10 m / min to avoid dislocation recovery due to temperature rise, with a deformation of 50% to further refine the grains. Solution treatment eliminates residual stress from cold rolling and improves the uniformity of precipitated phases during subsequent aging. Finally, it is air-cooled to room temperature to avoid micro-stress caused by rapid cooling. This cryogenic-aging process overcomes the strength-conductivity contradiction inherent in the traditional T6 process. Compared to conventional T6 treatment, this operation significantly improves product performance and involves no chemical treatments other than water quenching, meeting green manufacturing requirements.

[0040] Preferably, the surface strengthening treatment in step S8 includes the following steps:

[0041] S81, Laser Shock Enhancement: The surface of the thin strip is sandblasted and then covered with laser energy shock.

[0042] S82, coating treatment of thin strips: graphene / Al2O3 composite coating is applied to the strip using magnetron sputtering deposition technology, and finally vacuum annealing is performed to obtain the finished product.

[0043] In this step, the surface compressive stress induced by laser shock stabilization can inhibit crack initiation and propagation, improving fatigue life; the strengthening layer depth is ≥200μm, effectively covering stress concentration areas; a graphene / Al2O3 composite coating is used: graphene provides conductive pathways (reducing contact resistance), and Al2O3 improves corrosion resistance; the coating thickness is controlled at 50-100nm to balance functionality (conductivity / corrosion resistance) and processing costs; this operation can replace the traditional anodizing process, avoiding localized corrosion caused by micropores; the magnetron sputtering deposition temperature is <200℃ to prevent the substrate material from softening. Without this step, the product surface is prone to crack initiation under cyclic loading, shortening its lifespan, and the oxide film on the bare aluminum surface increases resistance, affecting the efficiency of conductive components.

[0044] The beneficial effects of this invention are:

[0045] 1. This invention optimizes the product's composition, simplifying the quantity and composition of components. The method of replacing Mn with Y significantly spheroidizes Mg2Si in alloy ingots and inhibits AlFeSi coarsening. Utilizing elemental synergy: the Mg / Si ratio is optimized (0.9–1.5 wt.% Mg vs. 0.25–0.85 wt.% Si), forming a β” phase (Mg2Si) that dominates strengthening, while avoiding excessive Si leading to coarse and brittle Si phases; the addition of Fe / Y composites allows Fe to form nano-Al-Fe-Si-Y phases, while Y inhibits grain boundary segregation and increases recrystallization temperature. The nano-β… (Mg) 2 Si) The main features are the phase and the highly cubic orientation grain matrix, which greatly improves the electrical conductivity and thermal conductivity.

[0046] 2. This invention optimizes the preparation process, utilizing cryogenic rolling combined with asynchronous hot rolling to form an ultrafine grain structure, resulting in a cubic orientation ratio >70%, reducing electron scattering; the β” phase and Al-Fe-Si-Y phase synergistically strengthen the structure, achieving a dislocation density of 102. 15 m -2 It also adopted single-roll thin strip continuous casting to directly prepare 0.5-1mm thin strips, eliminating the need for hot rolling and reducing energy consumption; multi-stage homogenization effectively saved the total processing time and improved the spheroidization rate of Al-Fe-Si-Y phase.

[0047] 3. This invention incorporates a low-frequency electromagnetic field during the raw material smelting process. The Lorentz force suppresses large-scale melt flow, forcing the melt to form micro-vortexes, eliminating the "dead zone" segregation inherent in traditional smelting, and eliminating the need for subsequent hexachloroethane refining, thus reducing toxic gas emissions and achieving green manufacturing. Setting the magnetic field frequency to <20Hz can suppress macroscopic convection in the melt and reduce dendrite segregation, while a magnetic field strength of 0.1–0.5T can refine the primary Al-Fe-Si-Y phase to 50–200 nm.

[0048] 4. This invention employs a combined deep cryogenic rolling and T6 heat treatment process, overcoming the contradiction between strength and conductivity inherent in the traditional T6 process. Compared to conventional T6 treatment, this operation significantly improves product performance, achieving a final thermal conductivity of 225 W / (mK), approximately 20% higher than traditional 6201 alloy sheets. The tensile strength can reach 210 MPa, meeting the current performance requirements of high-conductivity and high-thermal-conductivity aluminum alloys for high-power electronic circuit connections.

[0049] 5. This invention also utilizes laser shock peening and nano-coating to enhance the product's final lifespan and corrosion resistance. Testing revealed that the sample contained a high content of cubic orientation, thus significantly improving electrical and thermal conductivity. Attached Figure Description

[0050] Figure 1The images shown are SEM / BS / EDS images of the microstructure of the alloy after homogenization annealing in Example 1 of this invention.

[0051] Figure 2 The image shows the SEM / BS / EDS images of the microstructure of the alloy after homogenization annealing in Example 2 of this invention.

[0052] Figure 3 The image shows the SEM / BS / EDS images of the microstructure of the alloy after homogenization annealing in Example 3 of this invention.

[0053] Figure 4 The image shows the SEM / BS / EDS images of the microstructure of the alloy after homogenization annealing in Example 4 of this invention.

[0054] Figure 5 The image shows the SEM / BS / EDS images of the microstructure of the alloy after homogenization annealing in Example 5 of this invention.

[0055] Figure 6 The image shows the SEM / BS / EDS images of the microstructure of the alloy after homogenization annealing in Example 6 of this invention.

[0056] Figure 7 The image shows the SEM / BS / EDS images of the microstructure of the alloy after homogenization annealing in Example 7 of this invention.

[0057] Figure 8 The metallographic structures of the longitudinal sections of the T6 plate in Examples 3(a), 5(b), and 6(c) of this invention are shown.

[0058] Figure 9 The above are intensity contour maps of cubic orientation in Examples 3(a), 5(b), and 6(c) of the present invention. Detailed Implementation

[0059] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0060] The preparation process is as follows:

[0061] S1, Raw material pretreatment: Weigh the raw materials precisely according to the formula ratio, and use Al-Mg, Al-Si, Al-Fe, Al-Y master alloys to prepare the raw materials (the master alloys are specifically Al-20%Mg, Al-30%Si, Al-20%Fe, Al-10%Y). Sandblast the billet of the master alloy to remove the oxide scale, and ultrasonically clean it for 15 minutes in pure water at 55-65℃ and 20kHz. Then, vacuum low-temperature drying is carried out at 75-85℃ for 2 hours.

[0062] S2. First, 99.5 wt% industrial pure aluminum is placed in a pit-type resistance furnace and a graphite crucible for melting at a temperature of 730-780℃. At the same time, a low-frequency electromagnetic field is applied, specifically with a frequency of 5-20 Hz and a magnetic field strength of 0.1-0.5 T, perpendicular to the convection direction of the melt. After all the pure Al has melted, sufficient amounts of dried Al-Fe, Al-Y, Al-Mg, and Al-Si master alloys are added in sequence. A covering agent is sprinkled on top of the melt for protection.

[0063] S3. After confirming with a graphite rod that all the smelting raw materials in step S2 have melted, degas the melt. Use a vacuum rotary degasser with a vacuum degree <1kPa, rotor speed 500rpm, and blade tilt angle 45°. Inject the melt into the degassing chamber and continue degassing for 10-15 minutes until the bubbles are broken down to a diameter <0.5mm. After standing for 20 minutes, remove the slag and control the hydrogen content of the melt to <0.1mL / 100g.

[0064] S4, the degassed melt from step S3 is poured to obtain a thin strip; the melt is fed into a single-roll thin strip continuous casting machine and poured onto the roll surface through a nozzle, with a cooling rate controlled at 10. 3 ~10 6 K / s, directly producing thin strips with a thickness of 0.5 to 1 mm; among them, the copper roll diameter of the single roll thin strip continuous casting machine is 800 mm, and the roll speed is 20 to 30 m / s.

[0065] S5, Perform multi-stage gradient homogenization heat treatment on the thin strip obtained in step S4; First stage: hold at 360℃ for 2 hours; Second stage: hold at 520℃ for 8 hours; Third stage: hold at 580℃ for 6 hours, then cool with the furnace.

[0066] S6. The strip that has been homogenized in step S5 is preheated to 480-500℃ and held for 2 hours. Then, asynchronous hot rolling is performed with an upper and lower roll speed ratio of 1:1.2 until the total deformation reaches 80-90%. The warm rolling temperature is 200-250℃ and the deformation is 60-80%. Then, pre-aging treatment is performed for 1 hour, and finally, warm rolling is performed to obtain the hot-rolled strip.

[0067] S7, the hot-rolled strip obtained in step S6 is subjected to cryogenic rolling and T6 aging treatment; Cryogenic treatment with liquid nitrogen: the hot-rolled aluminum alloy strip is immersed in liquid nitrogen at -196℃ for 10 minutes; Cryogenic rolling: the cryogenically treated strip is cold-rolled at room temperature with a deformation of 50%; Solution treatment: the plate is heated to 540℃±5℃ and held for 1 hour to allow the β” phase to fully melt into the aluminum matrix; Water quenching at 20~30℃ with a cooling rate >200℃ / s to form a supersaturated solid solution; Artificial aging: held at 175℃±2℃ for 8 hours to promote the precipitation of nanoscale β” phase; after aging, the β” phase size is ≤50nm and the number density reaches 10. 22 m -3The strength is significantly improved, and it is air-cooled to room temperature.

[0068] S8, Perform surface strengthening treatment on the thin strip after step S7; Laser shock peening: Sandblast the surface of the thin strip, then set the laser energy density to 5-10 J / cm². 2 The pulse width is 10ns, the spot diameter is 3mm, the overlap rate is 50%, and the number of impacts is 3-5 times per area, covering the entire surface. The thin strip is coated: the graphene / Al2O3 composite coating is applied to the strip using magnetron sputtering deposition technology, and finally vacuum annealing is performed to obtain the finished product.

[0069] According to the above preparation method, the products of the examples and comparative examples were prepared according to different formulation ratios. The raw material usage of each example and comparative example is shown in Table 1 below. The main parameter settings in the preparation process of each example and comparative example are shown in Table 2 below.

[0070] Table 1. Raw material usage for each embodiment and comparative example.

[0071]

[0072] Table 2. Main parameters in the preparation process of the examples and comparative examples.

[0073]

[0074]

[0075] Comparative Example 1

[0076] It is basically the same as Example 3, except that a low-frequency electromagnetic field is not applied during melting in step S2, and all other conditions and operations are the same.

[0077] Comparative Example 2

[0078] It is basically the same as Example 3, except that a low-frequency electromagnetic field is applied simultaneously during melting in step S2, specifically at a frequency of 25Hz. All other conditions and operations are the same.

[0079] Comparative Example 3

[0080] The process is basically the same as in Example 3, except that the thin strip is subjected to multi-stage gradient homogenization heat treatment in step S5; the first stage is: holding at 360°C for 2 hours; the second stage is: holding at 580°C for 8 hours, followed by furnace cooling, and other conditions and operations are the same.

[0081] Comparative Example 4

[0082] It is basically the same as Example 3, except that the thin strip is not subjected to surface strengthening treatment, and all other conditions and operations are the same.

[0083] Comparative Example 5

[0084] The process is basically the same as in Example 3, except that in step S7, no liquid nitrogen cryogenic treatment or cryogenic rolling is performed, and T6 heat treatment is performed directly. All other conditions and operations are the same.

[0085] Test case

[0086] The alloy samples obtained in Examples 1-7 and Comparative Examples 1-5 were subjected to performance tests, and the test results are shown in Tables 1 and 2 below.

[0087] Table 1. Properties of alloy samples from Examples 1-7 and Comparative Examples 1-5

[0088] Example 1 51.6 58.5 220.3 Example 2 52.7 58.1 219.4 Example 3 53.5 57.6 227.6 Example 4 54.8 56.8 215.2 Example 5 55.7 54.5 213.5 Example 6 60.3 52.6 218.9 Example 7 61.8 50.7 215.6 Comparative Example 1 52.4 54.6 204.6 Comparative Example 2 53.5 56.1 205.5 Comparative Example 3 54.1 55.6 206.3 Comparative Example 4 55.6 55.3 212.6 Comparative Example 5 57.2 50.7 208.7

[0089] Table 2 Mechanical properties of alloy samples from Examples 1-7 and Comparative Examples 1-5

[0090] Example 1 183.6 165.8 24.3 Example 2 197.3 168.1 24.1 Example 3 180.3 176.8 23.7 Example 4 208.6 165.3 22.6 Example 5 220.7 175.6 21.3 Example 6 230.3 184.5 21.6 Example 7 254.7 172.3 20.4 Comparative Example 1 178.9 143.6 21.3 Comparative Example 2 182.4 148.3 20.6 Comparative Example 3 186.6 153.9 19.7 Comparative Example 4 162.3 142.6 15.2 Comparative Example 5 189.4 162.3 16.3

[0091] Based on the above test results, compared with Example 3, under the same conditions, the addition of an electromagnetic field in Comparative Example 1 significantly enhanced the electrical conductivity and also improved the thermal conductivity, proving that adding a low-frequency electromagnetic field during the smelting process of raw materials can improve the electrical conductivity of the product.

[0092] Compared to Example 3, under the same conditions, Example 2 showed that the magnetic field frequency was too high, exceeding 20Hz, and the conductivity decreased. Therefore, considering all factors, a magnetic field frequency below 20Hz can have a positive effect on the product performance.

[0093] Compared to Example 3, under the same conditions, Comparative Example 3 underwent a three-stage gradient homogenization heat treatment. Compared to a two-stage gradient homogenization heat treatment, the second stage of holding at 520°C for 8 hours can melt the low-melting-point eutectic phase (such as Al-Mg2Si, melting point ≈550°C), which reduces stress concentration and improves conductivity of the final spheroidized Al-Fe-Si-Y phase. This works in conjunction with subsequent rolling deformation to prevent crack initiation and improve other physical properties of the product.

[0094] Comparative Example 4 and Example 3, under identical conditions, showed a significant decrease in tensile strength and ductility without surface strengthening treatment. It can be seen that surface strengthening treatment, through laser shock induced surface compressive stress, can inhibit crack initiation and propagation, improving fatigue life; the strengthening layer depth is ≥200μm, effectively covering stress concentration areas; a graphene / Al2O3 composite coating is used: graphene provides conductive pathways (reducing contact resistance), and Al2O3 improves corrosion resistance; the coating thickness is controlled at 50-100nm to balance functionality (conductivity / corrosion resistance) and processing costs; this operation can replace the traditional anodizing process, avoiding localized corrosion caused by micropores; the magnetron sputtering deposition temperature is <200℃, preventing the substrate material from softening. Without this step, the product surface is prone to crack initiation under cyclic loading, shortening lifespan, and the oxide film on the bare aluminum surface increases resistance, affecting the efficiency of conductive components.

[0095] Comparative Example 5 and Example 3, under the same conditions, showed a significant decrease in electrical and thermal conductivity without cryogenic rolling. This is because immersing the warm-rolled aluminum alloy strip in liquid nitrogen for 10 minutes suppresses dislocation recovery and increases lattice distortion energy; freezing dislocation movement in an ultra-low temperature environment preserves the high-density dislocations formed during rolling, providing a strengthening foundation for subsequent cold rolling, ultimately greatly improving the overall performance of the product.

[0096] All technical features in this embodiment can be modified in appearance according to actual needs.

[0097] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present technical solution are within the protection scope of the present invention.

Claims

1. A novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting high-conductivity and high-thermal-conductivity electronic circuits, characterized in that: The product contains the following components by mass percentage: 0.9 wt.% Mg, 0.85 wt.% Si, 0.85 wt.% Fe, 0.1 wt.% Y, with the balance being Al and unavoidable impurities; It may contain the following components: 1.25 wt.% Mg, 0.65 wt.% Si, 0.65 wt.% Fe, 0.2 wt.% Y, with the balance being Al and unavoidable impurities; It may contain the following components: 1.45 wt.% Mg, 0.38 wt.% Si, 0.38 wt.% Fe, 0.18 wt.% Y, with the balance being Al and unavoidable impurities; It may contain the following components: 1.5 wt.% Mg, 0.25 wt.% Si, 0.25 wt.% Fe, 0.3 wt.% Y, with the balance being Al and unavoidable impurities; It may contain the following components: 1.45 wt.% Mg, 0.55 wt.% Si, 0.55 wt.% Fe, 0.13 wt.% Y, with the balance being Al and unavoidable impurities; It may contain the following components: 1.45 wt.% Mg, 0.81 wt.% Si, 0.82 wt.% Fe, 0.15 wt.% Y, with the balance being Al and unavoidable impurities; It may contain the following components: 1.45 wt.% Mg, 0.45 wt.% Si, 0.65 wt.% Fe, 0.21 wt.% Y, with the balance being Al and unavoidable impurities; Its preparation process includes the following steps: S1, Raw material pretreatment; S2, firstly, 99.5 wt% industrial pure aluminum is placed in a pit-type resistance furnace and a graphite crucible for melting at a melting temperature of 730~780℃. At the same time, a low-frequency electromagnetic field is applied. After all the pure Al has melted, sufficient amounts of dried Al-Fe, Al-Y, Al-Mg, and Al-Si master alloys are added in sequence. A covering agent is sprinkled on top of the melt for protection. The low-frequency electromagnetic field has a frequency of 5-20 Hz, a magnetic field strength of 0.1-0.5 T, and a direction perpendicular to the convection direction of the melt. S3. After confirming with a graphite rod that all the smelting raw materials in step S2 have melted, degas the melt. S4, the melt after degassing in step S3 is cast to obtain a thin strip; S5, Perform multi-level gradient homogenization heat treatment on the thin strip obtained in step S4; the multi-level gradient homogenization heat treatment specifically includes the following steps: S51, First stage: 360℃ heat preservation for 2 hours; S52, Second Stage: 520℃ heat preservation for 8 hours; S53, third stage: heat preservation at 580℃ for 6 hours, followed by furnace cooling; S6. The strip that has been homogenized in step S5 is preheated to 480~500℃ and held for 2 hours. Then, it is first subjected to asynchronous hot rolling and then pre-aging treatment for 1 hour. Finally, it is subjected to warm rolling to obtain hot-rolled strip. S7, the hot-rolled strip obtained in step S6 is subjected to cryogenic rolling and T6 aging treatment. The specific operations of cryogenic rolling and T6 heat treatment include the following steps: S71, Liquid nitrogen cryogenic treatment: The warm-rolled aluminum alloy strip is immersed in liquid nitrogen at -196℃ for 10 minutes. S72, cryogenic rolling: The thin strip after cryogenic treatment in step S71 is cold rolled at room temperature with a deformation of 50%; S73, solution treatment: heat the plate to 540℃±5℃ and hold for 1 hour to allow the β'' phase to fully dissolve in the aluminum matrix; water quench at 20~30℃ with a cooling rate of >200℃ / s to form a supersaturated solid solution; S74: Artificial aging: Holding at 175℃±2℃ for 8 hours promotes the precipitation of nano-scale β'' phase; after aging, the β'' phase size is ≤50nm, and the number density reaches [missing value]. Significantly improved strength, air-cooled to room temperature; S8. Perform surface strengthening treatment on the thin strip after step S7.

2. The novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting high-conductivity and high-thermal-conductivity electronic circuits according to claim 1, characterized in that: The specific operation of raw material pretreatment in step S1 is as follows: accurately weigh according to the formula ratio, use Al-Mg, Al-Si, Al-Fe, Al-Y master alloys to prepare raw materials, sandblast the billet of the master alloy to remove oxide scale, perform ultrasonic cleaning at 55~65℃ pure water and 20kHz for 15min, and then vacuum low temperature drying at 75~85℃ for 2h.

3. The novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting high-conductivity and high-thermal-conductivity electronic circuits according to claim 1, characterized in that: The specific operation of degassing in step S3 is as follows: a vacuum rotary degasser is set with a vacuum degree of <1kPa, a rotor speed of 500rpm, and a blade tilt angle of 45°. The melt is injected into the degassing chamber and degassing is continued for 10~15min. The bubbles are broken down to a diameter of <0.5mm. After standing for 20min, the slag is removed and the hydrogen content of the melt is controlled to <0.1mL / 100g.

4. The novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting high-conductivity and high-thermal-conductivity electronic circuits according to claim 1, characterized in that: The specific operation of pouring in step S4 is as follows: the molten metal is fed into the single-roll thin strip continuous casting machine and poured onto the roll surface through the nozzle, controlling the cooling rate to 10³-10. 6 K / s, directly producing thin strips with a thickness of 0.5~1mm; among which, the copper roll diameter of the single roll thin strip continuous casting machine is 800mm, and the roll speed is 20~30m / s.

5. The novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting high-conductivity and high-thermal-conductivity electronic circuits according to claim 1, characterized in that: The conditions for asynchronous hot rolling in step S6 are: the upper and lower roll speed ratio is 1:1.2, until the total deformation reaches 80~90%; the warm rolling temperature is 200~250℃, and the deformation is 60~80%.

6. The novel cubic-oriented Al-Mg-Si-Fe-Y aluminum alloy strip for connecting high-conductivity and high-thermal-conductivity electronic circuits according to claim 1, characterized in that: The specific operations of surface strengthening treatment in step S8 include the following steps: S81, Laser Shock Enhancement: The surface of the thin strip is sandblasted and then covered with laser energy shock. S82, coating treatment is carried out on the thin strip plate: using magnetron sputtering deposition technology for graphene on the plate composite coating, finally vacuum annealing treatment to get finished product.

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