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KR-20260064764-A - HIGH-STRENGTH Al-Si-Cu ALLOY WITH SCANDIUM ADDITION AND ITS MANUFACTURING METHOD

KR20260064764AKR 20260064764 AKR20260064764 AKR 20260064764AKR-20260064764-A

Abstract

The present invention relates to a high-strength Al-Si-Cu-Sc alloy and a method for manufacturing the same. By adding a small amount of Sc during the manufacturing process of the Al-Si-Cu-Sc alloy, the Al-Si-Cu-Sc alloy can be refined, thereby providing a material that is significantly lighter and has excellent mechanical properties compared to conventional steel.

Inventors

  • 김정석
  • 안성빈

Assignees

  • 조선대학교산학협력단

Dates

Publication Date
20260508
Application Date
20241029

Claims (7)

  1. Al-Si-Cu-Sc alloy containing 0.2 to 1.0 wt% of Sc and satisfying the following [Formula 1]. [Equation 1] 15 ≤ △S 1 ≤ 35 △S 1 (%) = Here, T₀ is the tensile strength of the Al-Si-Cu alloy without added Sc, and T1 is the tensile strength of the Al-Si-Cu-Sc alloy with added Sc.
  2. In paragraph 1, The phase alloy is a high-strength Al-Si-Cu-Sc alloy containing 1.0 to 6.0 wt% Cu.
  3. A heat-treated high-strength Al-Si-Cu-Sc alloy containing 0.2 to 1.0 wt% of Sc and satisfying the following [Equation 2]. [Equation 2] 40 ≤ △S 2 ≤ 70 △S 2 (%) = Here, T₀ is the tensile strength of an unheat-treated Al-Si-Cu alloy without added Sc, and T2 is the tensile strength of the Al-Si-Cu-Sc alloy after heat treatment.
  4. In paragraph 3, The above heat treatment is a high-strength Al-Si-Cu-Sc alloy comprising solution treatment at 400 to 600 ℃ for 3 to 5 hours and rapid cooling treatment after solution treatment.
  5. In paragraph 4, Al-Si-Cu-Sc alloy aged at 150 to 250°C for 4 to 6 hours after the above rapid cooling treatment.
  6. In the method for manufacturing a high-strength Al-Si-Cu-Sc alloy according to paragraph 3, A method for manufacturing a high-strength Al-Si-Cu-Sc alloy comprising the steps of (a) preparing a master alloy, (b) casting the alloy, and (c) heat treating.
  7. In paragraph 6, A method for manufacturing a high-strength Al-Si-Cu-Sc alloy in which the above master alloy is one or more selected from the group consisting of Al-Si, Al-Si-Cu, Al-Cu, and Al-Sc.

Description

High-strength Al-Si-Cu alloy with scandium addition and its manufacturing method The present invention relates to a high-strength Al-Si-Cu alloy with added scandium that is lightweight and has improved strength, suitable for use as a vehicle material, and a method for manufacturing the same. Recently, fuel efficiency regulations aimed at reducing carbon dioxide emissions in the automotive industry are being strengthened globally due to issues such as global warming, abnormal weather patterns, and rising oil prices caused by the depletion of fossil fuels. Regarding government-certified standard fuel efficiency and rating criteria, the carbon dioxide emission standard regulated by the European Union as of 2020 is 95 g/km. While South Korea's standard is slightly higher at 97 g/km, most vehicles among the top-selling domestic models emit an average of 148 g/km of carbon dioxide. Starting in 2021, if the average carbon dioxide emissions of cars sold in Europe exceed 95 g/km, a fine of 95 euros (approximately 130,000 won) must be paid for every gram exceeding the limit; in the case of Volkswagen, which recorded sales of 6.28 million units in 2019, this would result in fines exceeding 5 trillion won. Due to the impact of these regulations, there is a trend to lighten vehicle materials to improve fuel efficiency and reduce fuel costs. Typically, a 10% reduction in vehicle weight leads to a 7% increase in fuel efficiency, and since increased fuel efficiency reduces carbon dioxide emissions, it can help mitigate environmental problems. Aluminum (Al), used as a vehicle material, is lighter than steel, has excellent corrosion resistance, and possesses superior formability compared to other lightweight materials; consequently, its usage is increasing as a material applied to lightweight automobiles in recent years. Although Al-Mg-Si-Cu alloys have been introduced to reduce the weight of vehicle materials, they still fall short in terms of both weight reduction and strength. Therefore, there is a demand for alloys that can satisfy the requirements for increased strength and weight reduction simultaneously, which are necessary for vehicle materials. Figure 1 shows the change in Si particle size in an Al-Si-Cu-Sc alloy according to the present invention. Figure 2 is an optical microscope image of an Al-Si-Cu-Sc alloy according to the present invention. Figure 3 is the XRD analysis result of an Al-Si-Cu-Sc alloy according to the present invention. Figure 4 is a diagram of the equilibrium phase fraction of an Al-Si-Cu-Sc alloy according to the present invention. Figure 5 shows the mechanical properties of an Al-Si-Cu-Sc alloy according to the present invention. Figure 6 is an optical microscope image of a heat-treated Al-Si-Cu-Sc alloy according to the present invention. Figure 7 shows the Auger electron microscope analysis results of a heat-treated Al-Si-Cu-Sc alloy according to the present invention. FIG. 8 is a drawing of an aluminum melting furnace used in the alloy manufacturing method of the present invention. The present invention will be described in detail below by explaining preferred embodiments according to the present invention with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms, and these embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. In the drawings, the size of the components may be exaggerated or reduced for convenience of explanation. A range for weight % (wt%) may be understood as not including boundary values when it is greater than or less than, and as simply being designated as a range, or including boundary values when it is designated as greater than or less than. In the present invention, the addition amount of Sc being 0.0 weight% means that it is an Al-Si-Cu alloy. In addition, the Al-Si-Cu-Sc alloy produced according to the present invention may contain unavoidable impurities that are included in the alloy elements themselves or are unintentionally introduced during the manufacturing process, in addition to Al, Si, Cu, and Sc, which are intentionally added as alloying elements during the manufacturing process. In addition, the Al-Si-Cu-Sc alloy manufactured according to the present invention can be applied as a lightweight material for automobiles. The Al-Si-Cu-Sc alloy of the present invention will be described in detail below. The Al-Si-Cu-Sc alloy according to the present invention contains 0.2 to 1.0 weight% of Sc and can satisfy the following [Formula 1]. [Equation 1] 15 ≤ △S 1 ≤ 35 Here, △S 1 (%) = And, T0 is the tensile strength of the Al-Si-Cu alloy without Sc added, and T1 is the tensile strength of the Al-Si-Cu-Sc alloy with Sc added. The above △ S1 value may be 15 or more and 35 or less, or 17 or more and 30 or less, or 28 or more and 30 or l