Preparation method of high-thermal-conductivity aluminum alloy for energy storage battery pack

Abstract

The invention relates to a preparation method of a high-thermal-conductivity aluminum alloy for an energy storage battery pack, and belongs to the technical field of aluminum alloy production. The invention discloses a preparation method of a high-thermal-conductivity aluminum alloy for an energy storage battery pack. The preparation method comprises a component adjustment step, after component adjustment is completed, second-stage solid solution is carried out; aging treatment is carried out after the second-stage solid solution is completed; the component adjusting step specifically comprises the following steps: when the aluminum alloy is smelted, the temperature of a melt is 730-750 DEG C, the content of Fe is less than or equal to 0.15 wt%, the content of Cr reaches 0.05-0.10 wt%, and the content of rare earth reaches 0.05-0.15 wt%; according to the two-stage solid solution process, by accurately controlling the temperature and the time, sufficient solid solution of a second phase is guaranteed, meanwhile, abnormal growth of crystal grains and composition segregation are avoided, the purity and the structure uniformity of a matrix are improved, meanwhile, the process period is shortened, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a high-thermal-conductivity aluminum alloy for an energy storage battery pack and belongs to the technical field of aluminum alloy production. BACKGROUND

[0002] 6063 aluminum alloy is a typical alloy of the Al-Mg-Si system, and is widely used in the industrial profile field due to its good extrusion formability, medium strength and excellent corrosion resistance, and particularly occupies an important position in the heat dissipation structure of an energy storage battery pack. However, with the increasing requirements of high-energy-density battery systems on heat dissipation performance and structural reliability, the traditional 6063 aluminum alloy gradually shows limitations in comprehensive performance: on the one hand, the room-temperature strength of the 6063 aluminum alloy is difficult to meet the use requirements of the battery pack support, shell and other load-bearing structure parts under vibration and impact working conditions; on the other hand, although the intrinsic thermal conductivity of the alloy is high, in actual production, the strength and thermal conductivity are optimized in cooperation, and there are significant challenges in the influence of composition fluctuation and heat treatment process, if the strength is improved through conventional strengthening means, the thermal conductivity will decrease obviously, and it is difficult to meet the heat dissipation requirements of the battery pack under high power density; and when the thermal conductivity is simply pursued, the strength is difficult to meet the safe use requirements of the structure part.

[0003] In the prior art, the modification researches on the 6063 aluminum alloy are mainly focused on the optimization of a single performance. For example, CN111647780A adjusts the content of each trace element in the 6-series aluminum alloy, and promotes and induces sufficient nanoscale strengthening phase to precipitate at different stages of aging, improves the strength of the material on the basis of corrosion resistance; or optimizes the heat treatment process (such as aging temperature and time) to improve the uniformity of the structure, such as CN120060761A, which adopts twice aging heat treatment and rolling treatment in the processing technology of the 6063 aluminum alloy, and combines high solid solution treatment temperature, solves the problems of low efficiency and insufficient mechanical properties of the traditional process, and significantly improves the mechanical properties and uniformity of the aluminum alloy. However, they all have limited effects on the simultaneous improvement of strength and thermal conductivity, which limits the further application of the 6063 aluminum alloy in the high-requirement heat dissipation structure field of the energy storage battery pack. Therefore, developing a 6063 aluminum alloy modification technology capable of balancing high strength, high thermal conductivity and good plasticity has important engineering value and practical demand for improving the safety and reliability of the energy storage battery pack. SUMMARY

[0004] The application aims to solve the above problems, and in a first aspect, a preparation method of a high-thermal-conductivity aluminum alloy for an energy storage battery pack is provided.

[0005] The technical scheme for solving the above problems is as follows: A method for preparing a high thermal conductivity aluminum alloy for energy storage battery packs includes a composition adjustment step; a two-stage solution treatment after the composition adjustment is completed; and an aging treatment after the two-stage solution treatment is completed. The specific steps for adjusting the ingredients are as follows: When smelting aluminum alloys, the melt temperature is maintained at 730~750℃, and the Fe content is ≤0.15wt%, the Cr content is 0.05~0.10wt%, and the rare earth content is 0.05~0.15wt%. The secondary solid solution specifically refers to: 1) Solventize at 520~540℃ for 0.5~1.5h; 2) After heating to a temperature range of 540~560℃ by at least 5℃, dissolve for another 20~50 min to ensure that the second phase formed by Fe, Cr and rare earth elements in the alloy matrix is ​​refined and fully dissolved in the α-Al matrix.

[0006] The inventors discovered in their research that impurity elements such as Fe, which are difficult to completely remove during the production process using existing technologies, tend to form coarse second phases in the matrix. This not only reduces the plasticity of the material but also becomes a scattering center for heat conduction, further weakening the thermal conductivity and affecting the heat dissipation efficiency of the battery pack.

[0007] This invention comprises three steps: composition adjustment, secondary solution treatment, and aging treatment. By controlling the alloy composition and optimizing the heat treatment process, the coarse second phase in the matrix is ​​refined and dissolved, thereby improving the thermal conductivity and strength of the aluminum alloy. It is suitable for energy storage battery packs with high requirements for heat dissipation and structural performance.

[0008] When adjusting the composition, aluminum alloys are smelted at 730~750℃, with Fe content controlled at ≤ 0.15 wt%, Cr content at 0.05~0.10 wt%, and rare earth element (such as Ce, La, etc.) content at 0.05~0.15 wt%. Fe is the main impurity, easily forming a coarse second phase, reducing the material's plasticity and thermal conductivity, and is a major factor affecting heat dissipation performance; therefore, its content must be strictly controlled. Cr is a trace alloying element; appropriate addition can improve heat resistance, inhibit recrystallization, and have a certain influence on the type and distribution of the second phase. Rare earth elements can transform the second phase into a fine, uniform composite phase, while also refining grains, purifying the melt, and improving the uniformity of the microstructure, thereby improving thermal conductivity and mechanical properties.

[0009] After the component adjustment, secondary solid solution is carried out in two stages: first, solid solution at 520-540℃ for 0.5-1.5 hours to preliminarily dissolve part of the second phase; then, increase the temperature by at least 5℃ to 540-560℃ and solid solution for 20-50 minutes to further promote the coarse second phase, such as β-Fe phase, Al-(Fe, Cr) compound, etc., to be fully dissolved in the α-Al matrix. The staged solid solution process effectively refines and solidifies the coarse phase through pre-dissolution and fine-dissolution, avoids it from becoming a phonon scattering center for heat conduction or a stress concentration point, and provides a uniform precursor for the formation of fine nanometer precipitates in the subsequent aging treatment, thereby improving the strength while maintaining high thermal conductivity. This process can be adapted to different component systems to ensure a pure matrix and uniform structure.

[0010] Finally, aging treatment is carried out to precipitate fine and dispersed nanometer strengthening phase on the basis of solid solution, further improve the strength of the material, and not significantly reduce the thermal conductivity, finally obtaining an aluminum alloy material with high thermal conductivity and good mechanical properties.

[0011] As a preferred embodiment of the above technical solution, the aluminum alloy melted in the component adjustment step is 6063 aluminum alloy.

[0012] 6063 aluminum alloy itself has good extrusion formability, corrosion resistance and medium strength, and is a commonly used material for energy storage battery package heat dissipation structural parts (such as battery tray, shell support), which is directly related to the engineering applicability of the target product. Based on the original performance of 6063 aluminum alloy, the present application realizes the synergistic breakthrough of strength and thermal conductivity through subsequent two-stage solid solution and aging process.

[0013] As a preferred embodiment of the above technical solution, the rare earth is at least one of Ce and La.

[0014] The appropriate addition of rare earth elements can adjust the lattice vibration mode, reduce the formation of phonon scattering centers at high temperatures (such as avoiding the aggregation of coarse second phase or impurities), and assist in maintaining the thermal conductivity. Ce / La as a light rare earth element can effectively purify the grain boundary (reduce impurity aggregation), refine the grain, and indirectly improve the uniformity and plasticity of the material; at the same time, it can interact with the Mg-Si precipitate phase, optimizing the distribution of the precipitate phase.

[0015] As a preferred embodiment of the above technical solution, the aging treatment is two-stage aging treatment; specifically: 1) low-temperature aging at 110-130℃ for 100-150min; 2) increase the temperature by at least 40℃ to enter the temperature range of 160-180℃ for aging for 5-7h to promote the size of the nanometer precipitate phase to be concentrated in the range of 20-50 nm, improving the strength and thermal conductivity.

[0016] In the technical solution, the aging treatment adopts a two-stage aging process. By controlling the temperature and time in stages, the size and distribution of the nano precipitates are precisely controlled, avoiding the coarsening of the precipitates (reduction of thermal conductivity) caused by one-time high-temperature aging or the insufficient number of precipitates (insufficient strength) caused by low-temperature aging. Thus, the strength of the material is improved while maintaining high thermal conductivity, achieving a synergistic optimization of strength and thermal conductivity. Specifically, low-temperature aging (110-130°C) promotes the preliminary formation of GP zones (solute atom segregation zones) or small-sized precipitates, and high-temperature aging (160-180°C) promotes the uniform precipitation of Mg-Si-based nano precipitates and stabilizes them in the size range of 20-50 nm. On the one hand, the high density and uniform distribution of the precipitates can significantly improve the strength (such as yield strength and tensile strength) through dislocation pinning; on the other hand, the moderate size of the precipitates does not excessively scatter phonons, thus having a small impact on thermal conductivity, which helps to maintain high thermal conductivity, thus balancing strength and thermal conductivity.

[0017] As a preferred embodiment of the above technical solution, the high-thermal-conductivity aluminum alloy for energy storage battery packs has a thermal conductivity of not less than 210 W / m·K, a yield strength of not less than 210 MPa, a tensile strength of not less than 230 MPa, and an elongation of between 12% and 14%.

[0018] Compared with traditional 6063 aluminum alloys, the present application improves the strength and thermal conductivity through component and process synergy, and maintains a good elongation, making the comprehensive performance more suitable for the multiple requirements of high load-bearing, high heat dissipation, and deformation resistance of structural components for energy storage battery packs.

[0019] As a preferred embodiment of the above technical solution, the two-stage solid solution is as follows: 1) solid solution at 530°C for 1h; 2) heat to 540°C and solid solution for another 30 min to ensure that the second phase formed by Fe, Cr, and rare earth elements in the alloy matrix is refined and fully solid-solved in the α-Al matrix.

[0020] The temperature of 530°C can preliminarily dissolve part of the coarse second phase (such as β-Fe phase) and avoid composition segregation caused by too fast diffusion; after heating to 540°C for a short time (30 min), the remaining second phase (including composite phases formed by Fe, Cr, and rare earth elements) is completely solid-solved into the α-Al matrix, ensuring maximum purity of the matrix and reducing the risk of grain growth caused by long-time high-temperature solid solution. This preferred solution shortens the process cycle and improves production efficiency by more precise temperature and time control while ensuring complete solid solution of the second phase.

[0021] As a preferred embodiment of the above technical solution, the two-stage aging treatment is as follows: 1) low-temperature aging at 120°C for 2h; 2), aging at 175℃ for 6h, to promote the size of nano-precipitates to concentrate in the range of 20-50nm, to improve the strength and thermal conductivity.

[0022] Under the preferred process conditions, the low-temperature stage promotes the formation of uniformly distributed GP zones or small-size precipitates (pre-precipitation), providing nucleation basis for subsequent high-temperature precipitation; the high-temperature stage promotes the size of Mg2Si nano-precipitates to stabilize in the optimal range of 20-50nm, with uniform distribution and appropriate density, significantly improving the material strength through dislocation pinning (measured yield strength ≥ 212 MPa, tensile strength ≥ 234 MPa), and maintaining high thermal conductivity (measured up to 216.7 W / (m·K)) due to proper control of precipitate size to avoid excessive phonon scattering, achieving optimal balance of comprehensive performance.

[0023] As a preferred embodiment of the above technical solution, the high-thermal-conductivity aluminum alloy for energy storage battery packs has a material thermal conductivity of 216.7 W / m·K, a yield strength of 212 MPa, a tensile strength of 234 MPa, and an elongation of 13%.

[0024] This set of parameters achieves efficient synergy of strength, thermal conductivity, and plasticity, enabling the material to meet the high load-bearing and anti-deformation requirements of battery pack structural components while having excellent heat dissipation performance, and significantly outperforming traditional alloys in terms of comprehensive performance.

[0025] In summary, the present application has the following advantages: 1. The present application significantly improves the synergistic balance of thermal conductivity and mechanical properties of aluminum alloys. Through composition optimization and staged heat treatment process, the coarse second phase formed by Fe, Cr and rare earth elements in the matrix is effectively refined and solid-solved, suppressing its scattering effect on heat conduction and stress concentration effect, and achieving simultaneous improvement of material thermal conductivity and strength; 2. The present application effectively suppresses the coarse second phase formed by impurity elements (especially Fe) in traditional aluminum alloys, solving the key problem of plasticity reduction, thermal conductivity reduction, and affecting battery pack heat dissipation efficiency caused by such phase, significantly improving the service reliability of the material under high temperature working conditions; 3. The present application adopts a staged solid solution process, precisely controls the temperature and time to ensure sufficient solid solution of the second phase, while avoiding abnormal grain growth and composition segregation, improving the purity and uniformity of the matrix, and shortening the process cycle and improving the production efficiency; 4. The present application adopts a two-stage aging process to precisely control the size and distribution of nano-precipitates, significantly improving the material strength while maintaining high thermal conductivity and good elongation, achieving efficient synergy of strength, thermal conductivity, and plasticity; 5. This invention uses commonly used 6063 aluminum alloy as the base material. Through synergistic optimization of composition and process, it achieves a breakthrough improvement in performance without changing its good formability, corrosion resistance and other engineering applicability. The overall performance is more suitable for the multiple requirements of energy storage battery packs for structural components such as "high load-bearing capacity, high heat dissipation and deformation resistance".

[0026] 6. In summary, this invention achieves a synergistic improvement in the thermal conductivity, strength, and plasticity of 6063 aluminum alloy through precise proportioning of Fe, Cr, and rare earth elements and graded heat treatment process. It is particularly suitable for applications with stringent requirements for heat dissipation and structural reliability, such as energy storage battery packs. Attached Figure Description

[0027] Figure 1 Microscopic photographs of the metallographic structure of Example 1; Figure 2 This is a TEM image of Example 1; Figure 3 This is a low-magnification rendering of the microstructure defects such as coarse grains used in Example 1. Detailed Implementation

[0028] The present invention will be further explained and described below with reference to the accompanying drawings.

[0029] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. Any changes made by those skilled in the art after reading this specification, as long as they fall within the scope of the claims, will be protected by patent law. Example 1

[0030] The preparation and testing process of a high thermal conductivity aluminum alloy for energy storage battery packs is as follows: 1. Material and composition design This embodiment is based on 6063 aluminum alloy, and the mass percentage of its elements is optimized: Fe: 0.12% Cu: 0.25% Mn: 0.20% Mg: 1.0% Zn: 0.08% Cr: 0.08% Rare earth elements (Ce+La): 0.10% The balance consists of Al and unavoidable impurities.

[0031] 2. Process Flow S1. Smelting and Casting: In the smelting stage (740℃) of 6063 aluminum alloy, first, the content of iron element is controlled to 0.12%, the content of Cr is controlled to 0.08% by adding Al-Cr alloy, and the total content of Ce+La is controlled to 0.1% by adding rare earth mixed master alloy; after sufficient stirring, the ingot is obtained by casting, and the composition adjustment is completed; S2, homogenization annealing: The ingot is kept at 545℃ for 10 hours, and then air-cooled; S3, secondary solid solution treatment First step: 530℃, solid solution 1 h; Second step: heating to 540℃, solid solution 30 min; to ensure that the second phase formed by Fe, Cr and rare earth elements in the alloy matrix is refined and fully solid-soluted in the α-Al matrix; S4, secondary aging treatment: First step: 120℃, low-temperature aging 2 h; Second step: heating to 175℃, aging 6 h; to make the size of the nano precipitated phase concentrate in the range of 20~50 nm, and improve the strength and thermal conductivity.

[0032] 3, structure observation and illustration In order to visually display the technical effect of the present application in the aspect of structure regulation, the present embodiment adopts various microscopic and macroscopic observation methods to obtain the following key structure images: Figure 1 It is the metallographic structure microscope photo of example 1; it is taken by optical microscope (OM) at 400 times, which shows that after the secondary solid solution and secondary aging treatment, the grain structure in the alloy is uniformly refined, the second phase is small and uniformly distributed, there is no obvious coarse precipitation or segregation band, which reflects good structure uniformity and heat treatment effect.

[0033] Figure 2 It is the TEM graph of example 1; by high-resolution transmission electron microscopy observation, the Mg-Si system nano precipitated phase (such as Mg2Si or Mg5Si9, etc.) with size concentrated in the range of 20~50 nm in the material is clearly shown at nanoscale, which is uniformly and dispersedly distributed in the α-Al matrix, and is the key to realize high strength (dislocation pinning effect) and good thermal conductivity (size is not too large, and phonon scattering is weak).

[0034] Figure 3 It is the low-magnification rendering graph of example 1 for observing structure defects such as coarse grains; the graph is a macrostructure rendering image taken at 10 times, which is used to show the morphology of the material after heat treatment; from Figure 3It can be seen that there are no significant coarse grains, no macrosegregation, no shrinkage and other organizational defects. It shows that the secondary solid solution and the secondary aging effectively refine and inhibit the possible coarse phase during the process, reflecting the good uniformity of the organization and the effect of heat treatment.

[0035] Figures 1-3 Together, it constitutes a complete evidence of the micro-nano-macro multi-scale organization regulation effect of the present application, which directly reflects the comprehensive improvement of grain, precipitated phase and overall organizational quality by composition optimization and secondary heat treatment process. 4. Performance test results The aluminum alloy material prepared in this example was tested according to GB / T 228.1 (tensile strength, yield strength, elongation).

[0036] A Zwick Roell Z050 tensile testing machine was used to test the tensile properties of the profiles prepared under different process parameters. The elongation of the sample was accurately measured by a full-automatic extensometer makroXtens. By wire cutting technology, the tensile sample was prepared along the extrusion direction of the profile, with a thickness of 2.5mm. After cutting, the sample surface was polished using a polishing instrument to ensure smoothness without burrs, ensuring the accuracy of the test results.

[0037] The control parameters during testing are as follows: pre-load 5 MPa, yield point speed 1mm / min, test speed 1mm / min, elastic modulus measurement speed 1mm / min.

[0038] The results are as follows: material yield strength 212MPa, tensile strength 234MPa, elongation 13%.

[0039] The thermal conductivity of the material was tested according to ASTM E 1461-13 (2022).

[0040] Equipment name: thermal conductivity instrument LFA467 Environmental conditions: 23±2℃; humidity 50±5%RH Measured thermal conductivity: 216.717 W / m·K. Example 2

[0041] The process of this example is basically the same as that of example 1, only the proportion of alloy composition is adjusted, and the differences are as follows: Si: 0.7% Fe: 0.14% Cr: 0.06% Rare earth (Ce+La): 0.08% The other elements are equivalent to those in example 1.

[0042] The tested (test method same as example 1) thermal conductivity of the material of the example is 212.3 W / (m·K), the yield strength is 208 MPa, the tensile strength is 230 MPa, and the elongation is 12.1%. Example 3

[0043] The example has the same components as example 1, and only the aging process parameters are adjusted. The aging process adjustment is: First step: 110℃ × 120 min; Second step: 165℃ × 6.5 h; The tested (test method same as example 1) thermal conductivity of the material of the example is 214.1 W / (m·K), the yield strength is 210 MPa, the tensile strength is 232 MPa, and the elongation is 12.6 %.

[0044] Comparative example 1 Pure 6063 aluminum alloy is used, and the composition is not adjusted.

[0045] Process flow: melting → casting → 554℃ × 12h homogenization → 175℃ × 8h artificial aging.

[0046] Test results (test method same as example 1): thermal conductivity 200 W / (m·K), yield strength 185 MPa, tensile strength 210 MPa, elongation 9%.

[0047] Comparative example 2 Pure 6063 aluminum alloy is used, and the composition is not adjusted.

[0048] The process flow is the same as example 1 (only the composition adjustment step is omitted).

[0049] Test results (test method same as example 1): thermal conductivity 205 W / (m·K), yield strength 195 MPa, tensile strength 220 MPa, elongation 10%.

[0050] Comparative example 3 The same aluminum alloy as example 1 is used, but the process flow is the same as comparative example 1 (only the composition adjustment in the melting stage is the same as example 1).

[0051] Test results (test method same as example 1): thermal conductivity 208 W / (m·K), yield strength 201 MPa, tensile strength 219 MPa, elongation 11%.

[0052] From the comparison of the above examples and comparative examples, it can be seen that: The present application realizes excellent comprehensive performance of high thermal conductivity, high strength and good plasticity through the synergistic effect of "composition optimization (low Fe, appropriate amount of Cr and rare earth) + two-stage solid solution + two-stage aging".

[0053] Compared with the comparative examples, the embodiment 1 significantly reduces the content of elements such as Fe, Cu and Mn which are easy to form coarse second phases, and introduces Cr and rare earth elements, thereby optimizing the second phase type and the uniformity of the microstructure, and inhibiting the generation of coarse phases (such as β-Fe phase) from the source, which is beneficial to the formation of microstructure with high thermal conductivity and high strengthening in the subsequent heat treatment process. Although the process is optimized in the comparative example 2, it is proved that only relying on process optimization cannot realize the high thermal conductivity + high strength synergistic breakthrough of the present application. Although the composition is optimized in the comparative example 3, it is proved that only relying on composition adjustment cannot realize the high thermal conductivity + high strength synergistic breakthrough of the present application.

Claims

1. A method for preparing a high thermal conductivity aluminum alloy for energy storage battery packs, comprising a composition adjustment step; characterized in that: After the composition adjustment is completed, a two-stage solution treatment is carried out; after the two-stage solution treatment is completed, an aging treatment is performed. The specific steps for adjusting the ingredients are as follows: When smelting aluminum alloys, the melt temperature is maintained at 730~750℃, and the Fe content is ≤0.15wt%, the Cr content is 0.05~0.10wt%, and the rare earth content is 0.05~0.15wt%. The secondary solid solution specifically refers to: 1) Solventize at 520~540℃ for 0.5~1.5h; 2) After heating to a temperature range of 540~560℃ by at least 5℃, dissolve for another 20~50 min to ensure that the second phase formed by Fe, Cr and rare earth elements in the alloy matrix is ​​refined and fully dissolved in the α-Al matrix.

2. The method for preparing a high thermal conductivity aluminum alloy for an energy storage battery pack according to claim 1, characterized in that: The aluminum alloy smelted in the composition adjustment step is 6063 aluminum alloy.

3. The method for preparing a high thermal conductivity aluminum alloy for an energy storage battery pack according to claim 1, characterized in that: The rare earth element is at least one of Ce and La.

4. The method for preparing a high thermal conductivity aluminum alloy for an energy storage battery pack according to claim 1, characterized in that: The timeliness processing is a level-two timeliness processing; specifically: 1) Low-temperature aging at 110~130℃ for 100~150 min; 2) Increase the temperature by at least 40°C and age it in the temperature range of 160~180°C for 5~7 hours to promote the concentration of the nano-precipitated phase size in the range of 20~50nm, thereby improving the strength and thermal conductivity.

5. The method for preparing a high thermal conductivity aluminum alloy for an energy storage battery pack according to claim 1, characterized in that: The high thermal conductivity aluminum alloy used in the energy storage battery pack has a thermal conductivity of not less than 210 W / m·K, a yield strength of not less than 210 MPa, a tensile strength of not less than 230 MPa, and an elongation between 12% and 14%.

6. The method for preparing a high thermal conductivity aluminum alloy for an energy storage battery pack according to claim 1, characterized in that, The secondary solid solution specifically refers to: 1) Solvent at 530℃ for 1 hour; 2) Heat to 540℃ and then dissolve for 30 min to ensure that the second phase formed by Fe, Cr and rare earth elements in the alloy matrix is ​​refined and fully dissolved in the α-Al matrix.

7. The method for preparing a high thermal conductivity aluminum alloy for an energy storage battery pack according to claim 6, characterized in that, The secondary timeliness processing specifically includes: 1) Aging at 120℃ for 2 hours; 2) Heating to 175℃ and aging for 6 hours promotes the concentration of nano-precipitated phase size in the range of 20~50nm, thereby improving strength and thermal conductivity.

8. The method for preparing a high thermal conductivity aluminum alloy for an energy storage battery pack according to claim 7, characterized in that, The high thermal conductivity aluminum alloy used in the energy storage battery pack has a thermal conductivity of 216.7 W / m·K, a yield strength of 212 MPa, a tensile strength of 234 MPa, and an elongation of 13%.

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