WO2023195480A1 - Procédé d'inhibition de la fragilisation par l'hydrogène d'un matériau en alliage d'aluminium, et inhibiteur de fragilisation par l'hydrogène - Google Patents

Procédé d'inhibition de la fragilisation par l'hydrogène d'un matériau en alliage d'aluminium, et inhibiteur de fragilisation par l'hydrogène Download PDF

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WO2023195480A1
WO2023195480A1 PCT/JP2023/014043 JP2023014043W WO2023195480A1 WO 2023195480 A1 WO2023195480 A1 WO 2023195480A1 JP 2023014043 W JP2023014043 W JP 2023014043W WO 2023195480 A1 WO2023195480 A1 WO 2023195480A1
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aluminum alloy
phase
hydrogen embrittlement
alloy material
hydrogen
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PCT/JP2023/014043
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English (en)
Japanese (ja)
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一行 清水
裕之 戸田
正剛 山口
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国立大学法人岩手大学
国立大学法人九州大学
国立研究開発法人日本原子力研究開発機構
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Publication of WO2023195480A1 publication Critical patent/WO2023195480A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/10—Alloys based on aluminium with zinc as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon

Definitions

  • the present invention relates to a method for preventing hydrogen embrittlement of aluminum alloy materials and an agent for preventing hydrogen embrittlement of aluminum alloy materials.
  • Patent Document 1 describes that Zn contains 5.0 to 7.0%, Mg 1.0 to 3.0%, Cu 1.0 to 3.0%, and Cr 0.05 to 0.3%, Zr 0.05 to 0.25%, Mn 0.05-0.40%, Sc 0.05-0.35%, and one or more selected from them within a total amount of 0.05-0.5%.
  • the impurities are regulated to 0.25% or less and Fe to 0.25% or less, with the remainder being Al and other unavoidable impurities.
  • the average cooling rate to at least 400°C is 100°C/hr or more.
  • hot rolling is performed to a thickness of 50 mm or more at a temperature within the range of 300 to 440 degrees Celsius, followed by solution treatment, quenching, and artificial aging treatment to prevent intermetallic compounds with a circular equivalent diameter exceeding 5 ⁇ m.
  • a method for manufacturing an aluminum alloy thick plate with excellent strength and ductility is described, which produces a thick plate with a total area ratio of 2% or less.
  • Patent Document 2 contains 4.5 to 8.5 wt% of Zn, 1.5 to 3.5 wt% of Mg, and 0.8 to 2.6 wt% of Cu, and further contains at least 1 of Mn, Cr, Zr, V, and Ti.
  • the Fe content in the alloy must be restricted to 0.15 wt% or less to prevent corrosion cracking.
  • Patent Document 3 states that Zn5-8% by weight, Mg1.2-4.0% by weight, Cu more than 1.5% by weight and 4.0% by weight or less, Ag0.03-1.0% by weight, and Fe0.01-4% by weight. Contains 1.0% by weight, 0.005 to 0.2% by weight of Ti, 0.01 to 0.2% by weight of V, and 0.01 to 1.5% by weight of Mn, and 0.01 to 0.6% by weight of Cr. , Zr0.01-0.25% by weight, B0.0001-0.08% by weight, Mo0.03-0.5% by weight, and the remainder consists of aluminum and inevitable impurities. A high-strength aluminum alloy for welded structural materials with excellent stress corrosion cracking resistance is described.
  • Patent Document 4 describes a hydrogen embrittlement inhibitor for aluminum alloy materials that can prevent hydrogen embrittlement of aluminum alloy materials and is made of Al 7 Cu 2 Fe particles. Patent Document 4 focuses on the fact that hydrogen embrittlement cracking is dominated by local hydrogen distribution behavior and accumulation behavior in aluminum alloy materials, and suggests that a second phase with higher hydrogen trapping energy than the semi-coherent precipitate interface By adding particles (Al 7 Cu 2 Fe particles), hydrogen embrittlement caused by hydrogen trapped at the precipitate interface was prevented.
  • the problem to be solved by the present invention is to provide a method for preventing hydrogen embrittlement of aluminum alloy materials, which can effectively prevent or suppress hydrogen embrittlement by a method other than using Al 7 Cu 2 Fe particles or the like. .
  • a method for preventing hydrogen embrittlement of an aluminum alloy material including a step of forming a T phase in the aluminum alloy material.
  • the raw material composition containing aluminum and other metal additives is a low Zn/Mg composition containing Zn and Mg as metal additives at a Zn/Mg atomic ratio of 1.5 or less,
  • [4] Including the step of aging a raw material composition containing aluminum and other metal additives, The method for preventing hydrogen embrittlement of an aluminum alloy material according to [1] or [2], wherein the step of forming the T phase is a step of performing aging treatment at a temperature higher than 120°C.
  • a hydrogen embrittlement inhibitor for aluminum alloy materials that can prevent hydrogen embrittlement of aluminum alloy materials and is used to form particles inside the aluminum alloy materials, A hydrogen embrittlement inhibitor for aluminum alloy materials whose particles are in T phase.
  • FIG. 1 is a schematic diagram of hydrogen concentration in an aluminum alloy material in which a T phase is formed.
  • FIG. 2 is a schematic diagram of hydrogen concentration in an aluminum alloy material in which an ⁇ phase is formed.
  • FIG. 3 is a flowchart illustrating an example of the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention, together with a hydrogen embrittlement test method and a tensile test method.
  • FIG. 4 is a schematic diagram of an example of the crystal structure of Mg 32 (Al, Zn) 49 particles (an example of T phase) and its hydrogen trap sites.
  • FIG. 5 is a calculated graph of the relationship between the number of hydrogen atoms and hydrogen trap energy in an example of Mg 32 (Al, Zn) 49 particles.
  • FIG. 1 is a schematic diagram of hydrogen concentration in an aluminum alloy material in which a T phase is formed.
  • FIG. 2 is a schematic diagram of hydrogen concentration in an aluminum alloy material in which an ⁇ phase is formed.
  • FIG. 3 is a
  • FIG. 6(A) is a TEM image obtained by morphological analysis of the LT material of Comparative Example 1.
  • FIG. 6(B) is a TEM image of the diffraction pattern of the ⁇ phase ( ⁇ ' phase) of the LT material of Comparative Example 1.
  • FIG. 6(C) is a TEM image obtained by morphological analysis of the HT material of Example 1.
  • FIG. 6(D) is a TEM image of the diffraction patterns of the ⁇ phase ( ⁇ ' phase) and T phase of the HT material of Example 1.
  • FIG. 7 is a graph showing the relationship between strain and stress of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • FIG. 8 is a graph showing the area of intergranular cracks on the fracture surfaces of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • FIG. 9-1(A) is a graph showing the relationship between strain and fracture area ratio of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • FIG. 9-1(B) is a graph showing the relationship between strain and crack length (unit: ⁇ m) of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • Figures 9-2 (C) to (E) are 3D renderings of intergranular crack fracture of the aluminum alloy material of Comparative Example 1 (LT) with strains of 8.9%, 14.0%, and 17.8%, respectively. It is.
  • FIG. 9-1(A) is a graph showing the relationship between strain and fracture area ratio of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • FIG. 9-1(B) is a graph showing the relationship between strain and crack length (unit: ⁇ m) of the
  • FIG. 9-2 (F) is a SEM image obtained by morphological analysis of the fracture surface of the aluminum alloy material of Comparative Example 1 (LT).
  • Figures 9-3 (G) to (I) are 3D renderings of intergranular crack fracture of the aluminum alloy material of Example 1 (HT) with strains of 8.9%, 14.0%, and 17.8%, respectively. It is.
  • FIG. 9-3 (J) is a SEM image obtained by morphological analysis of the fracture surface of the aluminum alloy material of Example 1 (HT).
  • Figure 10(A) shows the trapped hydrogen concentration C H ( atom/m 3 ).
  • Figure 10(B) shows the hydrogen distribution ratio Occupancy trapped at each trap site in the aluminum alloy material of Example 1 (HT) at the crack tip before the tensile test (underformed) and after the tensile test.
  • This is a graph.
  • 11(A) to (D) show dislocations, grain boundaries (GB), vacancies, and ⁇ phase for the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT), respectively. It is a graph showing the hydrogen distribution ratio Occupancy trapped in ( ⁇ ' phase).
  • the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention includes a step of forming a T phase in the aluminum alloy material. With this configuration, the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention can effectively prevent or suppress hydrogen embrittlement by a method other than using Al 7 Cu 2 Fe particles or the like. Although the T phase is sometimes included in existing aluminum alloy materials, it was not known that it functions as a hydrogen embrittlement inhibitor for aluminum alloy materials.
  • T phase shows a schematic diagram of hydrogen concentration in an aluminum alloy material in which a T phase is formed.
  • the T phase (or T'phase; in this specification, the term T phase includes both T phase and T' phase without distinguishing between them) is dispersed in the aluminum base (aluminum base material). Therefore, hydrogen is concentrated inside the T phase.
  • Methods to prevent hydrogen embrittlement include (i) making the distribution of precipitates on grain boundaries less dense and coarse, (ii) reducing the grain boundary tilt angle (torsion angle) (creating a non-recrystallized structure), ( iii) Three types of structure control methods have been proposed to refine the crystal grains (for example, Goro Ito, Takehiko Eto, Yoshimitsu Miyagi, Mikihiro Kanno, "Al-Zn-Mg alloy", light metals, 38 ( (1988), p. 818-839). However, the effectiveness of these methods was unknown, and the specific mechanism was also unknown.
  • the present invention focuses on the fact that hydrogen embrittlement cracking is dominated by local distribution behavior and accumulation behavior of hydrogen within an aluminum alloy material.
  • the dominant factor causing hydrogen embrittlement is hydrogen trapped in precipitates (see Engineering Fracture Mechanics 216 (2019) 106503). Then, by determining the bonding energy between each microstructure of aluminum and hydrogen and calculating the hydrogen distribution within the aluminum alloy material, they quantitatively determined the amount of hydrogen at hydrogen trap sites that cause hydrogen embrittlement.
  • Nanoparticles that cause hydrogen embrittlement in aluminum alloys are ⁇ phase (or ⁇ ' phase.
  • ⁇ phase includes both ⁇ phase and ⁇ ' phase without distinguishing between them). They are dispersed in the alloy on the order of several to tens of nanometers.
  • FIG. 2 shows a schematic diagram of hydrogen concentration in an aluminum alloy material in which an ⁇ phase is formed.
  • the ⁇ phase is dispersed in the aluminum base (aluminum base material), and hydrogen is concentrated at the coherent or semi-coherent interface of the ⁇ phase.
  • the ⁇ phase has a particle composition of MgZn 2 , and the particle interface is between 0.35 eV/atom (coherent interface) and 0.56 eV/atom (semi-coherent interface). It has a hydrogen trap energy of .
  • Hydrogen embrittlement occurs in aluminum alloy materials due to the concentration of hydrogen in the ⁇ phase.
  • interfacial hydrogen removes the ⁇ phase, which is the source of hydrogen embrittlement, from the material and forms a T phase that can absorb hydrogen inside the material, thereby maintaining high strength and maintaining aluminum alloy materials (especially Al- It can fundamentally solve the hydrogen embrittlement of Zn-Mg alloy).
  • JP 2021-1881027 A describes that hydrogen embrittlement is prevented by preferentially distributing hydrogen inside coarse particles (second phase particles) while allowing the presence of the ⁇ phase. ing.
  • Hydrogen embrittlement cracking includes intergranular cracking and pseudo-cleavage cracking. In the present invention, it is preferable that intergranular crack fracture can be effectively prevented or suppressed, and it is more preferable that intergranular crack fracture and pseudo-cleavage cracking can be effectively prevented or suppressed. Preferred embodiments of the present invention will be described below.
  • An aluminum alloy material can be produced by a known process such as heat treatment, rolling, forging and/or casting, and aging treatment of a raw material composition (which may be a raw material mixture of aluminum and metal additives).
  • a raw material composition which may be a raw material mixture of aluminum and metal additives.
  • FIG. 3 is a flowchart illustrating an example of the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention, together with a hydrogen embrittlement test method and a tensile test method.
  • the melted or melted raw material composition is placed in a mold of a desired shape and cast.
  • the raw material composition that has a desired shape is homogenized.
  • the homogenized raw material composition is hot rolled (also referred to as hot rolling).
  • the hot rolled composition is subjected to thermal cycling (TC) and then electrical discharge machining (EDM).
  • the electrical discharge machined composition is polished and then subjected to solution treatment (ST). After solution treatment, aging treatment is performed at a desired temperature to obtain an aluminum alloy material.
  • the step of forming the T phase in the aluminum alloy material is not particularly limited, and the T phase can be formed by a known method.
  • a known method for example, J. JILM, 67, (2017) 5, 162-167 and J. of Materials Sci. & Tech. Examples include the method described in 85 (2021) 106-117.
  • a raw material composition containing aluminum and other metal additives contains Zn and Mg as metal additives at a Zn/Mg atomic ratio of 1.5 or less (preferably 1.2 or less, more preferably 1.2 or less). It is preferable that the process of forming the T phase is a process of rolling and aging the low Zn/Mg composition. When using a low Zn/Mg composition, there are no particular restrictions on the temperature and time of the aging treatment.
  • the step of forming the T phase includes a step of aging a raw material composition containing aluminum and other metal additives; Preference is given to processes carried out at temperatures higher than 120°C.
  • the aging treatment temperature is more preferably 130°C or higher, particularly preferably 150°C or higher.
  • the time of the aging treatment performed at a temperature higher than 120 ° C. is preferably 1 hour or more, more preferably 5 hours or more, and particularly 10 hours or more, from the viewpoint of facilitating the formation of the T phase. preferable.
  • the temperature and time of the aging treatment may be set within these preferable ranges from the viewpoint of making it easier to form the T phase.
  • timing of aging treatment performed at a temperature higher than 120°C is not particular restriction on the timing of aging treatment performed at a temperature higher than 120°C, but it is preferably performed after rolling and after solution treatment.
  • Step of aging treatment of low Zn/Mg composition A preferred embodiment when the step of forming the T phase is a step of aging the low Zn/Mg composition will be described.
  • the raw material composition (low Zn/Mg composition) containing aluminum and other metal additives contains Zn and Mg as metal additives, and the Zn/Mg atomic ratio is 0.2 to 0.8. It is particularly preferably 0.4 to 0.6, and even more preferably 0.4 to 0.6.
  • T phase is a type of dispersed phase in aluminum alloys, and the ratio of the constituent elements of Mg 32 (Al, Zn, Cu) 49 or Mg 32 (Al, Zn) 49 is chemically It refers to a composition that deviates within 30% from the stoichiometric composition.
  • the dispersed phase with the above composition is called T phase in aluminum alloy materials containing at least Zn and Mg (Al-Mg-Zn alloy materials), but in aluminum alloy materials whose parent phase has other compositions, it is called T phase. It may be referred to by its name, and any dispersed phase (preferably a precipitated phase, but other phases such as coarse particles may also be used) having the above composition is included in the T phase in this specification.
  • the T phase is a dispersed phase in aluminum with a wide range of component compositions, including Mg 22.4-41.6 (Al, Zn, Cu) 34.3-63.7 or Mg 22.4-41.6 ( (Al, Zn) 34.3 to 63.7 , Mg 27.2 to 36.8 (Al, Zn, Cu) 41.7 to 56.4 or Mg 27.2 to 36.8 (Al , Zn) 41.7 to 56.4 , and particularly preferably Mg 32 (Al, Zn, Cu) 49 or Mg 32 (Al, Zn) 49 .
  • the T phase is required to have a higher hydrogen trapping energy than the coherent precipitate interface.
  • the hydrogen trap energy of the T phase needs to be higher than at least 0.35 eV/atom of the coherent precipitate interface.
  • First-principles calculation refers to representing electronic states theoretically by mathematically solving the Schrödinger equation (without using experimental data or empirical parameters).
  • the distribution of hydrogen at each trap site can be calculated from the density of other hydrogen trap sites, such as grain boundaries, precipitates, and interstitials, and the bonding energy with hydrogen.
  • 3D mapping is possible.
  • the hydrogen trap energy of the T phase is preferably 0.40 eV/atom or more, more preferably 0.45 eV/atom or more, particularly preferably 0.50 eV/atom or more, and semi-coherent precipitates. It is particularly preferably higher than 0.55 eV/atom at the interface, most preferably from 0.55 to 0.56 eV/atom. The higher the hydrogen trapping energy of the T phase, the more hydrogen can be trapped inside the T phase, making it easier to prevent or suppress hydrogen embrittlement of the aluminum alloy material.
  • the trap site density of the T phase in the obtained aluminum alloy material is preferably 1.0 site/nm 3 or more, more preferably 5.0 site/nm 3 or more, and 7.0 site/nm 3 or more. It is particularly preferable that there be.
  • the dispersing phase By dispersing the T phase in the aluminum alloy, hydrogen embrittlement can be prevented or suppressed. Although it is sufficient that the dispersed phase (precipitated phase) contains the T phase, it is preferable to disperse the T phase alone in the aluminum alloy from the viewpoint of easily controlling hydrogen embrittlement of the aluminum alloy material. However, this does not prevent multiple types of dispersed phases (precipitated phases (precipitates)) from being dispersed in the aluminum alloy.
  • the shape of the T phase includes various shapes such as spherical, ellipsoidal, prismatic, cylindrical, cubic, rectangular parallelepiped, and scale-like, and is preferably spherical or ellipsoidal.
  • the average particle diameter of the T phase is preferably 0.1 to 50 nm.
  • the upper limit of the average particle diameter of the T phase is more preferably 20 nm or less, more preferably 10 nm or less, and particularly preferably 5.0 nm or less. It is more preferable that the lower limit of the average particle diameter of the T phase is 0.5 nm or more.
  • the average particle diameter of the T phase can be calculated as an arithmetic mean by observing the structure using a transmission electron microscope, for example.
  • the alloy composition of the aluminum alloy material obtained by applying the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention to the raw material aluminum alloy material has aluminum as the main component, and contains 50% by mass of aluminum. It is preferable to include the above.
  • the aluminum alloy material may be a new aluminum alloy material or an existing aluminum alloy material.
  • the hydrogen embrittlement preventive agent for aluminum alloy materials of the present invention conforms to JIS standards (for example, JIS H 4000:2014 for rolled plates; for cast materials, extruded materials, forged materials, etc., refer to the respective JIS standards). It is preferable to be able to prevent hydrogen embrittlement of aluminum alloy materials of existing alloys and/or new alloys that do not meet JIS standards.
  • the aluminum alloy material has aluminum as a main component, and preferably contains 50% by mass or more of aluminum.
  • a preferred embodiment of the aluminum alloy material is a pure aluminum alloy with a purity of 99.0% or more.
  • Examples of pure aluminum alloys include 1000 series alloys such as A1050, A1100, and A1200. Another preferred embodiment of the aluminum alloy material preferably contains at least Cu. Examples of the Al-Cu alloy include 2000 series alloys such as A2017 and A2024. Another preferred embodiment of the aluminum alloy material preferably contains at least Mn. Examples of the Al-Mn alloy include 3000 series alloys such as A3003, A3004, and A3005. Another preferred embodiment of the aluminum alloy material preferably contains at least Si. Examples of the Al--Si alloy include 4000 series alloys such as A4042, A4043, and A4343. Another preferred embodiment of the aluminum alloy material preferably contains at least Mg.
  • Al-Mg alloy examples include 5000 series alloys such as A5005, A5052, A5083, and A5182. Another preferred embodiment of the aluminum alloy material preferably contains at least Mg and Si. Examples of Al-Mg-Si alloys include 6000 series alloys such as A6061 and A6063. In one preferable embodiment of the aluminum alloy material, it is preferable that the aluminum alloy material contains at least Zn and Mg. Examples of the Al-Zn-Mg alloy include 7000 series alloys such as A7075 and A7050 alloys.
  • the aluminum alloy material contains at least Zn and Mg (it is an Al-Zn-Mg based alloy).
  • Al-Zn-Mg alloy is the highest strength alloy among practical aluminum alloy wrought materials, and is used in transportation equipment such as Shinkansen trains and aircraft. This is because the strength of this alloy system is currently rate-limited by hydrogen embrittlement.
  • a more preferred embodiment is a 7000 series alloy specified in JIS H 4000:2014 for rolled plates.
  • Another more preferable embodiment of the Al-Zn-Mg based alloy is an embodiment in which the aluminum alloy material contains Zn and Mg at a Zn/Mg atomic ratio of 1.5 or less.
  • the Zn/Mg atomic ratio is more preferably 1.2 or less, particularly preferably 1 or less, even more preferably 0.2 to 0.8, and 0.4 to 0. Even more particularly preferred is .6.
  • the aluminum alloy material may include Zn and Mg in an atomic ratio of Zn/Mg of more than 1 (or more than 1.2, or more than 1.5).
  • the hydrogen embrittlement inhibitor for aluminum alloy materials of the present invention is a hydrogen embrittlement inhibitor for aluminum alloy materials that can prevent hydrogen embrittlement of aluminum alloy materials and is used to form particles inside the aluminum alloy materials. , the particles are in T phase. Note that the particles of the dispersed phase (for example, the precipitated phase (precipitate)) contained in the aluminum alloy material may include other particles (such as the ⁇ phase) in addition to the T phase. Preferred embodiments of the hydrogen embrittlement inhibitor for other aluminum alloy materials are the same as the preferred embodiments of the method for preventing hydrogen embrittlement of aluminum alloy materials.
  • the aluminum alloy material obtained by using the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention has a T phase formed inside.
  • the shape of the aluminum alloy material is not particularly limited.
  • the aluminum alloy material may be in the form of a lump or particulate, and is preferably in the form of a lump.
  • the aluminum alloy material can be made into various known shapes such as a rolled plate, a cast material, an extruded material, and a forged material.
  • Method for manufacturing aluminum alloy material There are no particular restrictions on the method for producing the aluminum alloy material. It can be manufactured by the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention described above. A preferred embodiment of the method for producing an aluminum alloy material is the same as a preferred embodiment of the method for preventing hydrogen embrittlement of an aluminum alloy material.
  • Example 1 ⁇ Analysis of hydrogen distribution state> The reported crystal structure of Mg 32 (Al, Zn, Cu) 49 or Mg 32 (Al, Zn) 49 particles (T phase) (see Bergman et al., Acta Cryst., 10 (1957), 254) Based on this, a computational model was constructed and a first-principles calculation was used to search for sites where hydrogen can be trapped inside the T phase. As a result, it was discovered that there was a hydrogen trap site of 0.555 eV/atom.
  • FIG. 5 shows a calculated graph of the relationship between the number of hydrogen atoms and hydrogen trap energy in an example of Mg 32 (Al, Zn) 49 particles.
  • the T phase was a strong trap site with high density. Further, from FIGS. 4 and 5, it can be confirmed that there is a hydrogen trap site of 0.555 eV/atom inside the T phase (Mg 32 (Al, Zn) 49 ). From the above, it was found that the T phase has the effect of trapping hydrogen atoms more efficiently than coarse particles (second phase particles such as Al 6 Mn particles, Al 7 Cu 2 Fe particles, and Al 11 Mn 3 Zn 2 particles). Ta.
  • Example 1 and Comparative Example 1 Aluminum alloy materials satisfying the chemical composition of Al-5.6Zn-2.5Mg-1.6Cu (mass%) were prepared using the following two aging treatment temperatures. This aluminum alloy material is also an Al-Zn-Mg alloy containing 50% by mass or more of Al as a main component. A method for preventing hydrogen embrittlement of an aluminum alloy material was carried out using the method shown in FIG. 3 on a material for casting an aluminum alloy material of Al-5.6Zn-2.5Mg-1.6Cu (mass%). Specifically, homogenization was performed at 460°C for 6 hours, then the temperature was raised to 465°C for 24 hours, and hot rolling was performed at 400°C. Thickness was reduced by 87.5%.
  • Example 1 From 18mm to 2 .25mm), heating at 500°C for 30 minutes followed by 8 cycles of air cooling, electrical discharge machining (EDM), polishing, and solution treatment in a salt bath at 470°C for 1 hour. Solution treatment) was performed. Thereafter, the HT material of Example 1 was subjected to aging treatment at a high temperature of 150° C. for 16 hours in oil as a step of forming a T phase in the aluminum alloy material. On the other hand, the LT material of Comparative Example 1 was subjected to low-temperature aging treatment in oil at 120° C. for 4 hours as a step of forming the ⁇ phase. The obtained aluminum alloy material was subjected to humid environment aging in steam at 120°C for 1 hour to prepare test pieces with increased hydrogen concentration. And so.
  • FIG. 6(A), FIG. 6(B), FIG. 6(C), and FIG. 6(D) The aluminum alloy materials of each Example and Comparative Example 1 were observed using a TEM (transmission electron microscope). The obtained results are shown in FIG. 6(A), FIG. 6(B), FIG. 6(C), and FIG. 6(D).
  • FIG. 6(A) is a TEM image obtained by morphology analysis of the LT material of Comparative Example 1
  • FIG. 6(B) is a TEM image of the diffraction pattern of the ⁇ phase ( ⁇ ' phase) of the LT material of Comparative Example 1.
  • FIG. 6(C) is a TEM image obtained by morphology analysis of the HT material of Example 1
  • FIG. 6(D) is a TEM image of the diffraction patterns of the ⁇ phase ( ⁇ ' phase) and T phase of the HT material of Example 1. It is.
  • the diffraction pattern in Figure 6(D) was obtained by fast Fourier transform (FFT) of the high-resolution TEM image of the T phase marked by the arrow. Note that all images were taken along the [110] Al zone axis. From FIG. 6(C) and FIG. 6(D), it was found that in Example 1, an aluminum alloy material in which a T phase was formed inside was obtained. Note that in the HT material of Example 1, in addition to the T phase, an ⁇ phase was also observed.
  • FIG. 6(A) and FIG. 6(B) when aging treatment is performed at low temperature, that is, when the step of forming T phase in the aluminum alloy material is not performed, T phase is not formed inside. , it was found that only the ⁇ phase was formed.
  • FIG. 7 is a graph showing the relationship between strain and stress of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • FIG. 8 is a graph showing the area of intergranular crack (hydrogen embrittlement) on the fracture surfaces of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT). Note that the hydrogen embrittlement fracture surface ratio is preferably as small as possible.
  • FIG. 9-1(A) is a graph showing the relationship between strain and fracture area ratio of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • FIG. 9-1(B) is a graph showing the relationship between strain and crack length (unit: ⁇ m) of the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT).
  • FIG. 9-2 (C) to (E) are 3D renderings of intergranular crack fracture of the aluminum alloy material of Comparative Example 1 (LT) with strains of 8.9%, 14.0%, and 17.8%, respectively. It is.
  • FIG. 9-2 (F) is a SEM image obtained by morphological analysis of the fracture surface of the aluminum alloy material of Comparative Example 1 (LT).
  • FIG. 9-3 (G) to (I) are 3D renderings of intergranular crack fracture of the aluminum alloy material of Example 1 (HT) with strains of 8.9%, 14.0%, and 17.8%, respectively. It is.
  • FIG. 9-3 (J) is a SEM image obtained by morphological analysis of the fracture surface of the aluminum alloy material of Example 1 (HT).
  • Example 1 (HT) has the same strength as Comparative Example 1 (LT), which was aged at a low temperature, and is more elongated than Comparative Example 1 (LT). (The elongation at break (strain at break) was large). This is because in Example 1 (HT), the T phase suppresses the occurrence and propagation of intergranular crack (hydrogen embrittlement). That is, the method for preventing hydrogen embrittlement of an aluminum alloy material of the present invention effectively prevents hydrogen embrittlement by forming a T phase in an aluminum alloy material by a method other than using Al 7 Cu 2 Fe particles or the like. It was found that this is an extremely effective method for preventing hydrogen embrittlement of aluminum alloy materials.
  • FIGS. 10(A) and (B) show the obtained results.
  • Figure 10(A) shows the trapped hydrogen concentration C H ( atom/m 3 ).
  • Figure 10(B) shows the hydrogen distribution ratio Occupancy trapped at each trap site in the aluminum alloy material of Example 1 (HT) at the crack tip before the tensile test (underformed) and after the tensile test. This is a graph. From FIGS. 10A and 10B, it was found that in the aluminum alloy material of Example 1 (HT), hydrogen was preferentially distributed to the T phase. This result was the same whether it was before the tensile test (before deformation) or at the crack tip after the tensile test (after deformation).
  • Example 1 (LT) the hydrogen distribution state of the aluminum alloy material of Comparative Example 1 (LT) was similarly analyzed and compared with Example 1 (HT). The obtained results are shown in FIGS. 11(A) to (D). 11(A) to (D) show dislocations, grain boundaries (GB), vacancies, and ⁇ phase for the aluminum alloy materials of Example 1 (HT) and Comparative Example 1 (LT), respectively. It is a graph showing the hydrogen distribution ratio Occupancy trapped in ( ⁇ ' phase). 11(A) to (D), especially FIG. 11(D), it is clear that less hydrogen was trapped in the ⁇ phase ( ⁇ ' phase) in Example 1 (HT) than in Comparative Example 1 (LT). Understood.

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Abstract

La présente invention concerne un procédé d'inhibition de la fragilisation par l'hydrogène d'un matériau d'alliage d'aluminium, le procédé comprenant une étape de formation d'une phase T dans le matériau d'alliage d'aluminium. Ce procédé d'inhibition de la fragilisation par l'hydrogène d'un matériau en alliage d'aluminium est capable d'inhiber ou de supprimer efficacement la fragilisation par l'hydrogène par un moyen autre que l'utilisation de particules d'Al7Cu2Fe et analogues.
PCT/JP2023/014043 2022-04-06 2023-04-05 Procédé d'inhibition de la fragilisation par l'hydrogène d'un matériau en alliage d'aluminium, et inhibiteur de fragilisation par l'hydrogène WO2023195480A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03140433A (ja) * 1989-10-27 1991-06-14 Nkk Corp 耐食性にすぐれた高強度アルミニウム合金
JP2009221566A (ja) * 2008-03-18 2009-10-01 Kobe Steel Ltd 耐水素脆化特性に優れた高圧ガス容器用アルミニウム合金材
JP2011214149A (ja) * 2010-03-18 2011-10-27 Kobe Steel Ltd 高圧水素ガス貯蔵容器用アルミニウム合金材
JP2014101541A (ja) * 2012-11-19 2014-06-05 Kobe Steel Ltd 高圧水素ガス容器用アルミニウム合金材とその製造方法
JP2022512876A (ja) * 2018-11-12 2022-02-07 アレリス、ロールド、プロダクツ、ジャーマニー、ゲゼルシャフト、ミット、ベシュレンクテル、ハフツング ７ｘｘｘシリーズアルミニウム合金製品

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03140433A (ja) * 1989-10-27 1991-06-14 Nkk Corp 耐食性にすぐれた高強度アルミニウム合金
JP2009221566A (ja) * 2008-03-18 2009-10-01 Kobe Steel Ltd 耐水素脆化特性に優れた高圧ガス容器用アルミニウム合金材
JP2011214149A (ja) * 2010-03-18 2011-10-27 Kobe Steel Ltd 高圧水素ガス貯蔵容器用アルミニウム合金材
JP2014101541A (ja) * 2012-11-19 2014-06-05 Kobe Steel Ltd 高圧水素ガス容器用アルミニウム合金材とその製造方法
JP2022512876A (ja) * 2018-11-12 2022-02-07 アレリス、ロールド、プロダクツ、ジャーマニー、ゲゼルシャフト、ミット、ベシュレンクテル、ハフツング ７ｘｘｘシリーズアルミニウム合金製品

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