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CN-121992288-A - Method for reducing precipitation temperature of nano copper-rich phase and application thereof

CN121992288ACN 121992288 ACN121992288 ACN 121992288ACN-121992288-A

Abstract

The invention discloses a method for reducing precipitation temperature of a nano copper-rich phase and application thereof, and relates to the technical field of precipitation strengthening of metal materials. According to the invention, rare earth metal elements are added into the copper-containing steel, and the precipitation temperature of the nano copper-rich phase is reduced to not more than 480 ℃ through the regulation and control of the copper precipitation behavior by the rare earth metal elements. According to the invention, based on a rare earth element microcosmic regulation and control 9R-Cu phase low-temperature precipitation mechanism, the effective precipitation temperature of the 9R-Cu phase is reduced to below 480 ℃ through heterogeneous nucleation promotion effect of Ce atoms in the Cu precipitation process, so that the formation of a composite material interface brittle phase is avoided while excellent strengthening effect is ensured to the base material, and coordination and unification of base material strengthening and interface stability are realized.

Inventors

  • DING WENHONG
  • YANG CHUNHE
  • LI MINGQUAN
  • DING HONGYUAN
  • Gan Zuwei
  • ZANG ZHIQI

Assignees

  • 武汉科技大学

Dates

Publication Date
20260508
Application Date
20260115

Claims (10)

  1. 1. A method for reducing the precipitation temperature of a nano copper-rich phase is characterized in that rare earth metal elements are added into copper-containing steel, and the precipitation temperature of the nano copper-rich phase is reduced to not more than 480 ℃ through the regulation and control of the copper precipitation behavior of the rare earth metal elements.
  2. 2. The method of reducing the precipitation temperature of a nano copper-rich phase according to claim 1, wherein the 9R-Cu phase in the nano copper-rich phase has a ratio of 20 to 80%, and the precipitation temperature of the 9R-Cu phase is 420 to 480 ℃.
  3. 3. The method for reducing the precipitation temperature of a nano copper-rich phase according to claim 1, wherein the content of the rare earth element in the copper-containing steel material is 0.005-0. wt% by mass.
  4. 4. The method for reducing the precipitation temperature of a nano copper-rich phase according to claim 3, wherein the content of the rare earth metal element in the copper-containing steel material is 0.008-0.025 wt% by mass.
  5. 5. The method of reducing the precipitation temperature of a nano copper-rich phase according to claim 1, wherein the rare earth element is Ce.
  6. 6. The method for reducing the precipitation temperature of the nano copper-rich phase according to claim 1, wherein rare earth metal elements are added to molten steel to reach target content, and heat preservation treatment is carried out at a temperature of not more than 480 ℃ to realize the precipitation of the nano copper-rich phase; further, adding rare earth metal elements into molten steel at 1550-1700 ℃ in a rare earth intermediate alloy form; Further, the heat preservation treatment is carried out at the temperature of 420-480 ℃ for 0.2-3 h.
  7. 7. A copper-containing steel product, characterized in that it is obtained by the method according to any one of claims 1 to 6.
  8. 8. The copper-containing steel material according to claim 7, wherein the copper-containing steel material has a copper content of 0.7 to 1.5% by mass, a rare earth element content of 0.005 to 0.030% by mass, a carbon content of 0.03 to 0.15% by mass, a manganese content of 0.5 to 1.5% by mass, a silicon content of 0.1 to 0.6% by mass, and the balance being Fe and unavoidable impurities, and the nano copper-rich phase in the copper-containing steel material has a precipitation temperature of 420 to 480 ℃.
  9. 9. The copper-containing steel material according to claim 8, further comprising one or more of nickel 0.1 to 0.8%, titanium 0.005 to 0.05%, niobium 0.005 to 0.05%, and chromium 0.2 to 1.0% by mass.
  10. 10. A low-temperature strengthening method of a substrate of a composite material is characterized in that the copper-containing steel prepared by adopting the method of any one of claims 1-5 is used as a substrate, the heat treatment temperature of the substrate is controlled to be not more than 480 ℃, and the formation of an interfacial brittle phase is avoided while precipitation strengthening of the substrate is realized; further, the cladding material of the composite material is one or more of stainless steel, nickel-based alloy and titanium alloy.

Description

Method for reducing precipitation temperature of nano copper-rich phase and application thereof Technical Field The invention relates to the technical field of precipitation strengthening of metal materials, in particular to a method for reducing the precipitation temperature of a nano copper-rich phase. Background In extreme environmental applications such as ocean engineering and deep development, novel materials having multiple properties such as high strength, corrosion resistance, hydrogen embrittlement resistance, and microbial corrosion resistance are required. The layered metal composite material is an ideal choice because of the ability to achieve functional division, wherein the substrate assumes high strength and antimicrobial corrosion functions and the cover provides hydrogen resistance and strong corrosion resistance. In the design of composite material base material, precipitation strengthening is realized by adding Cu element, which is an important technical route for obtaining high strength and antimicrobial corrosion resistance. 9R-Cu precipitation strengthening technical advantages and temperature bottlenecks. In the nano copper-rich phase, the 9R-Cu phase has the best strengthening effect and the antimicrobial corrosion resistance due to the unique crystal structure and the coherent relation with the matrix. The nano precipitation strengthening technology disclosed in the Chinese patent ZL2019105119128 shows that the precipitation of the 9R-Cu phase can improve the yield strength of the steel by 200-300 MPa and obviously improve the anti-microbial corrosion performance. However, the effective precipitation temperature of the 9R-Cu phase in the prior art is generally above 600 ℃, and this high temperature requirement, although easy to achieve for elemental materials, is a key technical bottleneck for composite applications. The precipitation temperature of the 9R-Cu phase above 600 ℃ causes a series of technical dilemmas in the application of the high-strength hydrogen-resistant composite board substrate: First, when a heat treatment of 600 ℃ or higher is performed at the manufacturing stage, severe inter-diffusion of elements occurs at the interface of the composite material, and brittle intermetallic compounds such as Fe-Al, fe-Ti, fe-Cr and the like are formed. Research shows that at 600-650 ℃, the thickness of the brittle phase of the interface can reach 15-25 mu m, so that the peel strength of the interface is reduced, and the overall performance and service reliability of the composite material are seriously deteriorated. Second, in welding applications, the welding thermal cycle (peak temperature 1200-1400 ℃) causes the precipitated 9R-Cu phase in the heat affected zone to dissolve again completely, the strength of the weld zone can be reduced by about 200 MPa, and the antimicrobial corrosion performance is also significantly reduced. In order to restore the weld performance, postweld heat treatment is necessary, but the treatment temperature above 600 ℃ can reactivate the interface embrittlement process, so that a technical dead cycle of 'weld performance restoration-interface performance deterioration' is formed. Third, the residual stresses generated during manufacturing and service of the composite material require stress relief to ensure structural stability. For Cu-strengthened steel substrates that rely on nano-copper-rich phases for stress relaxation, redistribution and growth of the nano-copper-rich phases is an important mechanism for stress relief. However, the precipitation temperature above 600 ℃ of the traditional 9R-Cu phase causes the stress relief treatment to inevitably damage the interface performance, and limits the long-term service capability of the composite material under the high-stress environment. The root cause of the technical dilemma is that the prior art lacks effective means for regulating the precipitation temperature of the 9R-Cu phase. The traditional Cu precipitation strengthening technology mainly relies on the optimization of Cu content, cooling rate and aging process, but no matter what process optimization strategy is adopted, the temperature threshold of 600 ℃ is difficult to break through, the precipitation temperature of 9R-Cu phase cannot be changed fundamentally, and therefore the contradiction between the composite material interface stability cannot be solved all the time. The prior art only can compromise between the substrate strengthening effect and the interface stability, and coordination and unification of the substrate strengthening effect and the interface stability cannot be realized. Rare earth elements are applied to ferrous metallurgy, but are mainly concentrated in the traditional fields of deoxidation, desulfurization and the like. The prior art has limited knowledge of rare earth element regulation and precipitation behavior, and particularly the influence mechanism of Ce element on the 9R-Cu phase precipitation temperat