A magnesium alloy profile for a photovoltaic frame and a preparation method thereof

Abstract

This invention discloses a magnesium alloy profile for photovoltaic frames and its preparation method, relating to the field of magnesium alloy material technology. The magnesium alloy profile contains, by weight percentage: Zn: 4.5-5.5%, Mn: 0.5-1.0%, La or Ce master alloy: 0.2-0.5%, with the remainder being Mg and unavoidable impurity elements, the impurity element content being ≤0.1%. The method includes the following steps: Step 1, raw material preparation; Step 2, melting and forming; Step 3, homogenization treatment of magnesium alloy ingots; Step 4, extrusion processing of magnesium alloy ingots. The magnesium alloy profile prepared by this invention exhibits salt spray corrosion resistance comparable to existing aluminum alloy profiles, and its density is significantly lower than that of existing aluminum alloy profiles, resulting in a significant lightweight effect. Its yield strength, tensile strength, and elongation are all superior to or close to those of existing aluminum alloy profiles, and its mechanical properties meet the requirements for photovoltaic frames.

Description

Technical Field

[0001] This invention relates to the field of magnesium alloy materials technology, and in particular to a magnesium alloy profile for photovoltaic frames and its preparation method. Background Technology

[0002] With the rapid development of the global new energy industry, photovoltaic power generation, as an important form of clean and renewable energy, is seeing its application scope continuously expand, and the performance requirements for photovoltaic modules are also increasing. As a core structural component of photovoltaic modules, the photovoltaic frame mainly serves to fix and protect the photovoltaic glass and cells, as well as support the module and facilitate installation. Its performance directly affects the lifespan and reliability of the photovoltaic module.

[0003] Currently, aluminum alloy profiles are the most commonly used material for photovoltaic (PV) frames. Aluminum alloys possess certain strength, corrosion resistance, and processing performance, and are relatively inexpensive, leading to their widespread application in the PV field. However, as PV modules develop towards lighter and more efficient designs, the limitations of aluminum alloy frames are becoming increasingly apparent: aluminum alloys have a density of approximately 2.7 g / cm³, resulting in a relatively large weight that increases the overall weight of the PV module. This not only raises transportation and installation costs but also places higher demands on the load-bearing capacity of the roof, brackets, and other mounting structures. Furthermore, aluminum alloys have limited resistance to electrochemical corrosion. After long-term use in complex outdoor environments, such as high temperature, high humidity, and salt spray conditions, oxidation and corrosion can easily occur, affecting the structural stability of the frame and consequently shortening the lifespan of the PV module.

[0004] Magnesium alloys, currently the lowest density metallic structural material used in industrial applications, have a density of only 1.74 g / cm³, approximately 64% that of aluminum alloys. They possess significant advantages such as lightweight, high specific strength, good shock absorption, and strong recyclability, making them an ideal material to replace aluminum alloys in photovoltaic frame fabrication. However, the corrosion resistance and mechanical properties of ordinary magnesium alloys are insufficient to meet the requirements of photovoltaic frames. For example, Mg-Al-Zn based magnesium alloys, especially in complex outdoor environments, are prone to corrosion failure, and their balance between strength and elongation is poor, making them difficult to process and form.

[0005] To improve the performance of magnesium alloys, existing technologies often involve adding alloying elements and optimizing the manufacturing process to enhance their strength, corrosion resistance, and machinability. For example, adding Zn can improve the strength and toughness of magnesium alloys, adding Mn can improve their corrosion resistance and casting performance, and adding rare earth elements, such as La and Ce, can refine the grain size of magnesium alloys, thereby improving their mechanical properties and corrosion resistance. However, the proportions of different alloying elements and the manufacturing process parameters significantly affect the performance of magnesium alloy profiles, such as extrusion temperature and extrusion speed. Therefore, how to rationally design the alloy composition and optimize the manufacturing process to ensure that magnesium alloy profiles possess excellent mechanical properties, corrosion resistance, and machinability, thus meeting the requirements of photovoltaic frames, has become a pressing technical problem to be solved.

[0006] To address the shortcomings of the existing technologies, this invention provides a magnesium alloy profile for photovoltaic frames and its preparation method. By rationally proportioning Mg-Zn-Mn-La / Ce alloying elements and optimizing the smelting, homogenization, and extrusion processes, a lightweight, high-strength, and corrosion-resistant magnesium alloy profile is prepared. This solves the problems of heavy weight and insufficient corrosion resistance of existing aluminum alloy frames, as well as the poor mechanical properties and high processing difficulty of ordinary magnesium alloy frames, thus meeting the actual application requirements of photovoltaic frames. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by proposing a magnesium alloy profile for photovoltaic frames and its preparation method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A magnesium alloy profile for photovoltaic frames comprises, by weight percentage: Zn: 4.5-5.5%, Mn: 0.5-1.0%, La or Ce master alloy: 0.2-0.5%, with the remainder being Mg and unavoidable impurity elements, wherein the content of the impurity elements is ≤0.1%.

[0009] Preferably, the magnesium alloy profile composition contains, by weight percentage: Zn: 5%, Mn: 0.75%, La: 3.5%, with the remainder being Mg and unavoidable impurity elements.

[0010] Preferably, the magnesium alloy profile composition contains, by weight percentage: Zn: 5.2%, Mn: 0.9%, Ce: 0.4%, with the remainder being Mg and unavoidable impurity elements.

[0011] A method for preparing a magnesium alloy profile for photovoltaic frames, the method being implemented based on a magnesium alloy profile for photovoltaic frames, includes the following steps: Step 1: Prepare raw materials; Pure zinc ingots, pure manganese ingots, pure magnesium ingots, and La master alloy are selected as raw materials according to weight percentage; Step 2: Melting and shaping; Place the pure magnesium ingots into the melting furnace and heat the furnace to 720-760℃. After the pure magnesium ingots are completely melted, add the pure zinc ingots, pure manganese ingots, and La master alloy in sequence while stirring. The stirring speed in the melting furnace is 300-500 r / min to ensure that the elements are mixed evenly. Then a refining agent is added to the melt to remove gases and impurities. After refining, let it stand for 10-15 minutes until there is no slag on the surface of the melt. Then pour the melt into a mold preheated to 200-250℃ and cool it to form a magnesium alloy ingot. Step 3: Homogenization treatment of magnesium alloy ingots; The surface of the obtained magnesium alloy ingot was cleaned to remove the oxide scale and defects, and then placed in a heating furnace for homogenization treatment, and then cooled to room temperature with the heating furnace. Step 4: Magnesium alloy ingot extrusion processing; The homogenized magnesium alloy ingots are cut into the required size and fed into the extrusion cylinder of the extrusion press; Before extrusion, preheat the magnesium alloy ingot and extrusion cylinder to 280-350℃ to ensure uniform temperature. Then start the extruder, control the extrusion exit speed to 0.1-2m / min, and control the extrusion ratio to 15-25:1. After extrusion molding, magnesium alloy profiles for photovoltaic frames are obtained.

[0012] Preferably, in step 1, the purity of the pure magnesium ingot, pure zinc ingot, and pure manganese ingot is ≥99.9%, with the balance being unavoidable impurity elements; the purity of La in the La master alloy is ≥99%, with the balance being unavoidable impurity elements.

[0013] Preferably, in step 2, the refining agent is hexachloroethane.

[0014] Preferably, in step 2, the refining time is 15-25 minutes and the refining temperature is maintained at 720-740℃.

[0015] Preferably, in step 3, the homogenization treatment temperature is 380-420℃, and the holding time is 8-12h.

[0016] Preferably, in step 4, the preheating time for the magnesium alloy ingot and the extrusion cylinder is 2-4 hours.

[0017] Preferably, in step 4, after extrusion molding, the surface of the magnesium alloy profile for the photovoltaic frame is cleaned to remove surface oxide scale and burrs, thus obtaining the finished product.

[0018] The beneficial effects of this invention are as follows: 1. The magnesium alloy profile of this invention adopts a Mg-Zn-Mn-La / Ce alloy system. By rationally proportioning the alloying elements, the mechanical properties and corrosion resistance are synergistically improved. In particular, the precise control of Mn, La, and Ce elements significantly optimizes the corrosion resistance of the alloy. Among them, Mn can form stable intermetallic compounds with harmful impurities Fe and Al in the magnesium alloy, such as the Al-Mn-Fe phase, which effectively encapsulates or precipitates the impurities, thereby reducing the potential difference between the impurities and the Mg matrix, inhibiting the occurrence of microgalvanic corrosion, and reducing the risk of corrosion failure. This invention controls the Mn content at 0.5-1.0%, which can further enhance the corrosion resistance control effect. La and Ce rare earth elements can form a dense and stable oxide film on the surface of the magnesium alloy, effectively blocking the contact between the external corrosive medium and the Mg matrix. At the same time, it can refine the grains, reduce the corrosion channels at the grain boundaries, and further improve the corrosion resistance of the alloy.

[0019] 2. The magnesium alloy profile of the present invention has a density of only 1.75-1.80 g / cm³, which is more than 30% lighter than aluminum alloy. The lightweight effect is significant, which can effectively reduce the overall weight of photovoltaic modules, reduce transportation and installation costs, and reduce the load-bearing pressure on the installation carrier. It is not prone to corrosion failure during long-term use in complex outdoor environments, which greatly extends the service life of photovoltaic frames.

[0020] 3. By optimizing the preparation process, the magnesium alloy ingot and extrusion cylinder are preheated to 280-350℃ before extrusion, and the extrusion exit speed is controlled at 0.1-2m / min. Combined with homogenization treatment, the magnesium alloy profile has excellent mechanical properties. The extrusion process parameters can be adjusted according to the different application requirements of photovoltaic frames to obtain suitable mechanical properties and meet the structural strength and impact resistance requirements of photovoltaic frames.

[0021] 4. The preparation method of the present invention is simple and highly controllable. The process parameters for smelting, homogenization and extrusion are reasonable. It does not require complex equipment and high costs, and is suitable for large-scale production. At the same time, magnesium alloys have good recyclability, which is in line with the industrial trend of green environmental protection and sustainable development, and can further reduce the environmental impact of the photovoltaic industry.

[0022] 4. The magnesium alloy profile of the present invention has excellent processing performance and is not prone to defects such as cracking and deformation during extrusion molding. It can be directly processed into various cross-sectional shapes required for photovoltaic frames, adapting to photovoltaic modules of different specifications. It has strong versatility and broad application prospects. Attached Figure Description

[0023] Figure 1 This is a mechanical property diagram of a magnesium alloy profile for photovoltaic frames according to Embodiment 1 of the present invention.

[0024] Figure 2This is a microstructure diagram of a magnesium alloy profile for photovoltaic frames according to Embodiment 1 of the present invention. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0026] A magnesium alloy profile for photovoltaic frames, comprising, by weight percentage: Zn: 4.5-5.5%, Mn: 0.5-1.0%, La or Ce master alloy: 0.2-0.5%, with the remainder being Mg and unavoidable impurity elements, the impurity element content being ≤0.1%.

[0027] This invention, through phase diagram analysis and considering the mechanisms of action and performance requirements of each alloying element, identifies the optimal content range for each element. This ensures that the alloy forms stable beneficial phases and avoids the precipitation of harmful phases within the room temperature and preparation process temperature range, thereby guaranteeing the mechanical properties, corrosion resistance, and processing performance of magnesium alloy profiles. The specific analysis is as follows: I. Mg-Zn Phase Diagram Analysis: The solid solubility of Zn in α-Mg decreases with decreasing temperature, reaching approximately 2.5% at room temperature and approximately 6.2% at melting temperatures of 720-760℃. When the Zn content exceeds the solid solubility at the corresponding temperature, a MgZn strengthening phase will precipitate from the α-Mg solid solution during the cooling process. The MgZn phase has good bonding with the α-Mg matrix, has no obvious hard and brittle characteristics, and can significantly improve the strength of the alloy, achieving a balance between strength and toughness. When the Zn content is in the range of 4.5-5.5%, at the melting temperature, most of the Zn can be dissolved in the α-Mg matrix, and there is no obvious undissolved Zn phase. After cooling to room temperature, the equilibrium phase of the alloy is α-Mg solid solution with an appropriate amount of MgZn strengthening phase, with a precipitation ratio of 3-8%. At this time, the strengthening phase is evenly distributed, which can give full play to the precipitation strengthening effect, while avoiding the alloy becoming brittle due to excessive MgZn phase. If the Zn content is less than 4.5%, the amount of MgZn phase precipitation in the phase diagram is insufficient (less than 3%), the strengthening effect is weak, and it is difficult to achieve the mechanical strength required for photovoltaic frames; If the Zn content is greater than 5.5%, which is close to the upper limit of solid solubility at the melting temperature, a large amount of MgZn phase (greater than 8%) will precipitate after cooling, and a continuous MgZn phase network will easily form, causing the alloy matrix to become brittle and the elongation to decrease significantly, which cannot meet the impact resistance requirements of photovoltaic frames. Therefore, based on phase diagram analysis, the Zn content range is 4.5-5.5%.

[0028] II. Analysis of Mn, La, and Ce element content: The design of Mn, La, and Ce element content in this invention is based on their mechanism of action in magnesium alloys, combined with the synergistic effect with Zn element, to ensure that the ratio of Mn to Ce is 4.5-5.5% to achieve optimal synergistic performance.

[0029] (1) Mn element: Mn has a low solid solubility in Mg, about 0.3% at room temperature, and does not form a hard and brittle harmful phase with Mg. Its main function is to improve corrosion resistance, refine grains and strengthen in synergy with Zn element. Controlling the Mn content to 0.5-1.0% allows a small amount of Mn to dissolve in the α-Mg matrix, while the remaining Mn forms stable intermetallic compounds such as Al-Mn-Fe with impurities Fe and Al, thus inhibiting microgalvanic corrosion. At the same time, it can refine the α-Mg grains, improve processing performance, and synergistically enhance the alloy strength with MgZn strengthening.

[0030] If the Mn content is less than 0.5%, the corrosion resistance and grain refinement effect are poor; if the Mn content is greater than 1.0%, an excessive amount of Mn-Mg binary hard and brittle phase will precipitate, reducing the alloy elongation and processing performance. Therefore, the Mn content range is confirmed to be 0.5-1.0%.

[0031] (2) La or Ce elements: La and Ce have a strong affinity for Mg and can form a small amount of LaMg or CeMg intermetallic compounds with Mg. When they precipitate in appropriate amounts, they do not cause hard brittleness. Their core function is to refine the grains, improve corrosion resistance and enhance the strengthening effect of Zn elements. By controlling the total content of La or Ce to 0.2-0.5%, α-Mg grains can be significantly refined without forming an excessive amount of hard and brittle phase, promoting the formation of a dense oxide film on the surface, while enhancing the strengthening effect of the MgZn2 phase, and achieving a balance between mechanical properties and corrosion resistance in synergy with Zn and Mn elements. If the La or Ce content is less than 0.2%, the grain refinement and corrosion resistance improvement effects are not obvious; if the La or Ce content is greater than 0.5%, a large amount of hard and brittle rare earth phases will precipitate, resulting in a decrease in alloy toughness and an increase in processing difficulty. Therefore, the total La or Ce content is confirmed to be in the range of 0.2-0.5%.

[0032] In summary, by analyzing the phase diagram to clarify the Zn content range, and combining the action mechanism of Mn, La, or Ce and their synergistic effect with Zn, the optimal ratio of each element was determined: Zn: 4.5-5.5%, Mn: 0.5-1.0%, La or Ce: 0.2-0.5%. This ensures that the alloy forms a stable and beneficial phase composition, achieving optimal synergy in mechanical properties, corrosion resistance, and processing performance, and fully meeting the application requirements of photovoltaic frames.

[0033] In this invention, the roles of each alloying element are as follows: Zn (zinc) is a key strengthening element in magnesium alloys. It forms the MgZn phase with Mg, which is uniformly distributed within the magnesium alloy matrix, providing precipitation strengthening. Simultaneously, Zn exhibits significant grain boundary segregation, preferentially accumulating at grain boundaries, inhibiting grain growth, promoting grain refinement, and further enhancing the strengthening effect of the alloy, significantly improving the yield strength and tensile strength of magnesium alloys. Furthermore, Zn can improve the casting and processing properties of magnesium alloys and reduce the difficulty of extrusion molding. This invention controls the Zn content to 4.5-5.5%. If the Zn content is too low, the strengthening effect and grain boundary segregation are not significant, making it difficult to achieve the mechanical strength required for photovoltaic frames. If the Zn content is too high, it will lead to the excessive precipitation of MgZn compounds and excessive grain boundary segregation, making the magnesium alloy brittle, reducing elongation, and affecting the impact resistance of the frame.

[0034] Magnesium (Mn) is primarily used to improve the corrosion resistance of magnesium alloys. Mn can form MnFe compounds with harmful impurities (such as Fe) in magnesium alloys, preventing Fe from causing electrochemical corrosion. Simultaneously, Mn possesses excellent grain boundary segregation capabilities, forming segregated layers at grain boundaries to hinder grain growth and migration, effectively promoting grain refinement. This synergistic effect with precipitation strengthening further enhances the alloy's strengthening effect, improving its strength and toughness. Furthermore, Mn can improve the melting and casting properties of magnesium alloys, reducing defects such as porosity and shrinkage cavities in ingots. This invention controls the Mn content to 0.5-1.0%. If the Mn content is too low, corrosion resistance, grain boundary segregation effect, and grain refinement effect are poor; if the Mn content is too high, it will lead to the appearance of hard and brittle phases in the alloy, and excessive grain boundary segregation, reducing elongation and processing performance.

[0035] Rare earth elements La or Ce: La and Ce can work synergistically, and both have a strong grain boundary segregation effect. They can accumulate in large quantities at grain boundaries, forming stable segregation regions, effectively inhibiting grain growth, significantly refining magnesium alloy grains, and reducing the mechanical property degradation caused by coarse grains. At the same time, the grain boundary segregated La or Ce elements can form a synergistic strengthening effect with the matrix, further enhancing the strengthening effect of the alloy and improving the overall mechanical properties of the alloy. In addition, rare earth elements La or Ce can also improve the casting and extrusion processing properties of magnesium alloys, reducing the risk of cracking during extrusion; and can form a dense oxide film on the surface of magnesium alloys, effectively improving the corrosion resistance of magnesium alloys and extending the service life of photovoltaic frames. This invention controls the total content of La or Ce to 0.2-0.5%. If the content is too low, the effects of grain refinement, grain boundary segregation, and corrosion resistance improvement are not obvious; if the content is too high, it will lead to rare earth phase aggregation, forming a hard and brittle structure, reducing the toughness and processing performance of the alloy.

[0036] Specifically, the composition of magnesium alloy profiles by weight percentage includes: Zn: 5%, Mn: 0.75%, La: 3.5%, with the remainder being Mg and unavoidable impurity elements.

[0037] Specifically, the composition of magnesium alloy profiles by weight percentage includes: Zn: 5.2%, Mn: 0.9%, Ce: 0.4%, with the remainder being Mg and unavoidable impurity elements.

[0038] Example 1: A method for preparing a magnesium alloy profile for photovoltaic frames, comprising the following steps: Step 1: Prepare raw materials; The magnesium alloy profile composition by weight percentage is: Zn: 4.5%, Mn: 1%, La: 0.2%, with the remainder being Mg and unavoidable impurity elements; pure zinc ingots, pure manganese ingots, pure magnesium ingots, and La master alloy are selected as raw materials according to weight percentage; the purity of pure magnesium ingots, pure zinc ingots, and pure manganese ingots is ≥99.9%, with the remainder being unavoidable impurity elements, and the purity of La in the La master alloy is ≥99%, with the remainder being unavoidable impurity elements.

[0039] Step 2: Melting and shaping; Place pure magnesium ingots into a melting furnace and heat the furnace to 720°C. After the pure magnesium ingots have completely melted, add pure zinc ingots, pure manganese ingots, and La master alloy in sequence while stirring. The stirring speed in the melting furnace is 300 r / min to ensure that the elements are mixed evenly. Then, a refining agent, namely hexachloroethane, is added to the melt. The refining time is 15 minutes, and the refining temperature is maintained at 720°C to remove gases and impurities from the melt. After refining, let it stand for 10 minutes until there is no slag on the surface of the melt. Then pour the melt into a mold preheated to 200°C and cool it to obtain a magnesium alloy ingot. Step 3: Homogenization treatment of magnesium alloy ingots; The surface of the obtained magnesium alloy ingot was cleaned to remove the oxide scale and defects. Then it was placed in a heating furnace for homogenization treatment at a temperature of 380℃ for 8 hours. After that, it was cooled to room temperature with the heating furnace. Step 4: Magnesium alloy ingot extrusion processing; The homogenized magnesium alloy ingots are cut into the required size and fed into the extrusion cylinder of the extrusion press; Before extrusion, the magnesium alloy ingot and extrusion cylinder are preheated to 280°C for 2 hours to ensure uniform temperature. Then start the extruder, control the extrusion exit speed to 0.1m / min, and control the extrusion ratio to 25:1. After extrusion molding, obtain the magnesium alloy profile for photovoltaic frame. After extrusion molding, the surface of the magnesium alloy profile used for the photovoltaic frame is cleaned to remove the surface oxide scale and burrs, resulting in the finished product.

[0040] Example 2: A method for preparing a magnesium alloy profile for photovoltaic frames, comprising the following steps: Step 1: Prepare raw materials; The magnesium alloy profile composition by weight percentage is: Zn: 5%, Mn: 0.8%, La: 0.35%, with the remainder being Mg and unavoidable impurity elements; pure zinc ingots, pure manganese ingots, pure magnesium ingots, and La master alloys are selected as raw materials according to weight percentage; the purity of pure magnesium ingots, pure zinc ingots, and pure manganese ingots is ≥99.9%, with the remainder being unavoidable impurity elements, and the purity of La in the La master alloy is ≥99%, with the remainder being unavoidable impurity elements.

[0041] Step 2: Melting and shaping; Place pure magnesium ingots into a melting furnace and heat the furnace to 740°C. After the pure magnesium ingots have completely melted, add pure zinc ingots, pure manganese ingots, and La master alloy in sequence while stirring. The stirring speed in the melting furnace is 400 r / min to ensure that the elements are mixed evenly. Then, a refining agent, namely hexachloroethane, is added to the melt. The refining time is 20 minutes, and the refining temperature is maintained at 730°C to remove gases and impurities from the melt. After refining, let it stand for 12 minutes until there is no slag on the surface of the melt. Then pour the melt into a mold preheated to 220°C and cool it to form a magnesium alloy ingot. Step 3: Homogenization treatment of magnesium alloy ingots; The surface of the obtained magnesium alloy ingot was cleaned to remove the oxide scale and defects. Then it was placed in a heating furnace for homogenization treatment at a temperature of 400℃ for 10 hours. After that, it was cooled to room temperature with the heating furnace. Step 4: Magnesium alloy ingot extrusion processing; The homogenized magnesium alloy ingots are cut into the required size and fed into the extrusion cylinder of the extrusion press; Before extrusion, the magnesium alloy ingot and extrusion cylinder are preheated to 320°C. The preheating time for the magnesium alloy ingot and extrusion cylinder is 3 hours to ensure uniform temperature. Then start the extruder, control the extrusion exit speed to 1m / min, and control the extrusion ratio to 25:1. After extrusion molding, obtain the magnesium alloy profile for photovoltaic frame. After extrusion molding, the surface of the magnesium alloy profile used for the photovoltaic frame is cleaned to remove the surface oxide scale and burrs, resulting in the finished product.

[0042] Comparative Example 1 uses 6063 aluminum alloy profiles commonly used in the prior art for photovoltaic frames. This 6063 aluminum alloy profile is used as Comparative Example 1 of this application.

[0043] Table 1: Performance comparison of Example 1, Example 2 and Comparative Example 1, the results are shown in the table below: Sample Name Density (g / cm³) Yield strength (MPa) Tensile strength (MPa) Elongation (%) Salt spray corrosion resistance (neutral salt spray, 100h) Example 1 1.78 258 303 11 The surface shows no obvious corrosion, and the corrosion rate is ≤0.01mm / a. Example 2 1.81 206 295 18 The surface shows no obvious corrosion, and the corrosion rate is ≤0.01mm / a. Comparative Example 1 2.70 240 290 10 The surface showed no obvious corrosion, and the corrosion rate was ≤0.02mm / a. As can be seen from Examples 1-2 and Comparative Example 1, the magnesium alloy profile prepared by the present invention has salt spray corrosion resistance comparable to that of existing aluminum alloy profiles, and its density is significantly lower than that of existing aluminum alloy profiles, resulting in a significant lightweight effect; its yield strength, tensile strength and elongation are superior to or close to those of existing aluminum alloy profiles, and its mechanical properties meet the requirements for photovoltaic frame applications.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A magnesium alloy profile for photovoltaic frames, characterized in that, The magnesium alloy profile composition contains, by weight percentage: Zn: 4.5-5.5%, Mn: 0.5-1.0%, La or Ce master alloy: 0.2-0.5%, with the remainder being Mg and unavoidable impurity elements, the content of which is ≤0.1%.

2. The magnesium alloy profile for photovoltaic frames according to claim 1, characterized in that, The magnesium alloy profile contains, by weight percentage: Zn: 5%, Mn: 0.75%, La: 3.5%, with the remainder being Mg and unavoidable impurity elements.

3. The magnesium alloy profile for photovoltaic frames according to claim 1, characterized in that, The magnesium alloy profile contains, by weight percentage: Zn: 5.2%, Mn: 0.9%, Ce: 0.4%, with the remainder being Mg and unavoidable impurity elements.

4. A method for preparing a magnesium alloy profile for a photovoltaic frame, the method being implemented based on the magnesium alloy profile for a photovoltaic frame as described in claim 2, characterized in that, Includes the following steps: Step 1: Prepare raw materials; Pure zinc ingots, pure manganese ingots, pure magnesium ingots, and La master alloy are selected as raw materials according to weight percentage; Step 2: Melting and shaping; Place the pure magnesium ingots into the melting furnace and heat the furnace to 720-760℃. After the pure magnesium ingots are completely melted, add the pure zinc ingots, pure manganese ingots, and La master alloy in sequence while stirring. The stirring speed in the melting furnace is 300-500 r / min to ensure that the elements are mixed evenly. Then a refining agent is added to the melt to remove gases and impurities. After refining, let it stand for 10-15 minutes until there is no slag on the surface of the melt. Then pour the melt into a mold preheated to 200-250℃ and cool it to form a magnesium alloy ingot. Step 3: Homogenization treatment of magnesium alloy ingots; The surface of the obtained magnesium alloy ingot was cleaned to remove the oxide scale and defects, and then placed in a heating furnace for homogenization treatment, and then cooled to room temperature with the heating furnace. Step 4: Magnesium alloy ingot extrusion processing; The homogenized magnesium alloy ingots are cut into the required size and fed into the extrusion cylinder of the extrusion press; Before extrusion, preheat the magnesium alloy ingot and extrusion cylinder to 280-350℃ to ensure uniform temperature. Then start the extruder, control the extrusion exit speed to 0.1-2m / min, and control the extrusion ratio to 15-25:

1. After extrusion molding, magnesium alloy profiles for photovoltaic frames are obtained.

5. The method for preparing a magnesium alloy profile for a photovoltaic frame according to claim 4, characterized in that, In step 1, the purity of the pure magnesium ingot, pure zinc ingot, and pure manganese ingot is ≥99.9%, with the balance being unavoidable impurity elements; the purity of La in the La master alloy is ≥99%, with the balance being unavoidable impurity elements.

6. The method for preparing a magnesium alloy profile for a photovoltaic frame according to claim 4, characterized in that, In step 2, the refining agent is hexachloroethane.

7. The method for preparing a magnesium alloy profile for a photovoltaic frame according to claim 6, characterized in that, In step 2, the refining time is 15-25 minutes and the refining temperature is maintained at 720-740℃.

8. The method for preparing a magnesium alloy profile for a photovoltaic frame according to claim 4, characterized in that, In step 3, the homogenization treatment temperature is 380-420℃, and the holding time is 8-12h.

9. The method for preparing a magnesium alloy profile for a photovoltaic frame according to claim 4, characterized in that, In step 4, the preheating time for the magnesium alloy ingot and extrusion cylinder is 2-4 hours.

10. A method for preparing a magnesium alloy profile for a photovoltaic frame according to claim 4, characterized in that, In step 4, after extrusion molding, the surface of the magnesium alloy profile for the photovoltaic frame is cleaned to remove the surface oxide scale and burrs, thus obtaining the finished product.

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