• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a spun, rolled and / or forging product made of aluminum-based alloy with a thickness of at least 25 mm comprising (in% by weight) Zn 6.70 - 7.40; Mw 1.50 - 1.80; Cu 2.20 - 2.60, with a Cu to Mg ratio of at least 1.30; Zr 0.04 - 0.14; Mn 0 - 0.5; Ti 0 - 0.15; V 0 - 0.15; Cr 0 - 0.25; Fe 0 - 0.15; If 0 - 0.15; impurities = 0.05 each and = 0.15 total. The invention also relates to the method of manufacturing such a product. The products according to the invention are particularly advantageous because they have a very favorable compromise between static mechanical strength, toughness and environmental-assisted cracking performance under high stress and wet environment conditions.
    公开号:FR3068370A1
    申请号:FR1756275
    申请日:2017-07-03
    公开日:2019-01-04
    发明作者:Ricky WHELCHEL；Erembert Nizery；Diana Koschel；Jean-Christophe Ehrstrom；Alireza Arbab
    申请人:Constellium Issoire SAS；
    IPC主号:
    专利说明:

    The present invention relates generally to aluminum-based alloys and, more particularly, aluminum-based alloys Al-Zn-Cu-Mg, in particular for aerospace applications.
    Description of Related Art
    Al-Zn-Cu-Mg aluminum-based alloys have been used extensively in the aerospace industry for many years. With the evolution of aircraft structures and taking into account efforts to reduce both weight and cost, an optimal compromise is constantly sought between strength, toughness and resistance to corrosion. In addition, improvements in foundry, rolling and heat treatment techniques provide other advantages allowing better control of the balance diagram of an alloy.
    Thick rolled, forged or extruded products, made of Al-Zn-Cu-Mg aluminum-based alloys are used in particular to produce high-resistance structural parts, fully machined, for the aeronautical industry, for example. example of wing elements such as ribs, side members, chassis and the like, generally machined in thick sections obtained by forging.
    The characteristic values obtained for the various properties such as static mechanical resistance, fracture toughness, resistance to corrosion, sensitivity to hardening, resistance to fatigue, as well as the level of residual stresses determine the overall characteristic of the product, the possibility of using it advantageously for a structural designer, as well as the ease with which it can be used in other manufacturing stages such as, for example, machining.
    Among the properties listed above, some are often in conflict by nature and it is generally necessary to find a compromise. Such conflicts of properties can be, for example, static mechanical resistance with respect to toughness, or mechanical resistance with respect to corrosion resistance.
    Among the properties of corrosion or cracking assisted by the environment (FAE), it is possible to make a distinction between the FAE under conditions of strong stresses and humid environment, and the FAE under conditions of cracking by corrosion under Standard stress (CSC), such as those of ASTM G47, the test pieces being tested using alternative immersion and drying cycles in NaCl solution (ASTM G44) and typically using lower stresses. A standard CSC cracking fault can occur under the action of an anodic dissolution mixture due to local potential differences and hydrogen embrittlement, embrittlement being the most likely failure mode for AWF under conditions of high stress and humid environment (see for example JRSCULLY, GA YOUNG JR, SW SMITH, “Hydrogen embrittlement of aluminum and aluminum based alloys” (hydrogen embrittlement of aluminum and base alloys aluminum), in “Gaseous hydrogen embrittlement of materials in energy technologies”, edited by RP Glangloff and BP Somerday, Woodhead Publishing 2012, pages 707 -768).
    The development of a high strength 7XXX alloy with low sensitivity to AWF under conditions of high stress and humid environment would represent a significant improvement. In particular, it is sought to obtain alloys having a higher resistance than known alloys such as AA7010 or AA7050, but having a resistance to FAE at least equivalent under conditions of high stress and humid environment.
    Al-Zn-Mg-Cu alloys having a high fracture toughness, a high mechanical strength and a high resistance to cracking by standard CSC are known in the prior art.
    US Patent 5,312,498 discloses a method of manufacturing an aluminum-based alloy product having better delamination resistance and better fracture toughness, comprising an aluminum-based alloy composition formed essentially of 5.5-10.0% zinc by weight, 1.75-2.6% magnesium by weight and about 1.8-2.75% copper by weight, the rest being aluminum and d other elements. The aluminum-based alloy is wrought, heat-treated, quenched and aged to make a product with better corrosion resistance and better mechanical properties. The amounts of zinc, magnesium and copper are balanced in stoichiometric proportions, so that once the precipitation has essentially ended at the end of the tempering process, there are no excess elements left.
    The American patent 5,560,789 describes alloys of the AA 7000 series which benefit from a high mechanical resistance, as well as a process making it possible to obtain them. In weight content, the alloys are composed of 7 to 13.5% of Zn, 1 to 3.8% of Mg, of 0.6 to 2.7% of Cu, of 0 to 0.5% of Mn, of 0 to 0.4% Cr, 0 to 0.2% Zr, other elements up to 0.05% each and 0.15% in all, the rest being Al, the properties corrosion is however not mentioned.
    US Patent No. 5,865,911 describes an aluminum alloy composed essentially (weight content) of about 5.9 to 6.7% zinc, 1.8 to 2.4% copper, 1.6 to 1.86 % magnesium, 0.08 to 0.15% zirconium, the rest being aluminum, random elements and impurities. The ‘911 patent particularly mentions the compromise between static mechanical strength and toughness.
    U.S. Patent No. 6,027,582 describes aluminum alloy AlZn-Mg-Cu alloy products, rolled, forged or extruded, of thickness greater than 60 mm and having a composition of (weight content) Zn: 5.7 to 8.7; Mg: 1.7 to 2.5; Cu: 1.2 to 2.2; Fe: 0.07 to 0.14; Zr: 0.05 to 0.15 with Cu + Mg <4.1 and Mg> Cu. The ‘582 patent also describes improvements in the field of quench sensitivity.
    US Patent No. 6,972,110 discloses an alloy which preferably contains (content by weight) Zn: 7 to 9.5; Mg: 1.3 to 1.68 and Cu 1.3 to 1.9; and which advises to keep Mg + Cu <3.5. The ‘110 patent presents a method using a tempering treatment comprising three stages, intended to improve the resistance to cracking by corrosion under stress. A three-step income takes time and is difficult to master. It would be desirable to obtain a high corrosion resistance without necessarily having to carry out such a heat treatment.
    PCT patent application No. W02004090183 presents an alloy essentially comprising (content by weight): Zn: 6.0 to 9.5; Cu: 1.3 to 2.4; Mg: 1.5 to 2.6; Mn and Zr <0.25 but preferably within a range of 0.05 to 0.15 for high Zn contents, the other elements being less than 0.05 each, and 0.25 in all, the rest consisting of aluminum, with (content by weight): 0.1 [Cu] + 1.3 <[Mg] <0.2 [Cu] + 2.15, preferably 0.2 [Cu] + 1.3 <[Mg] <0.1, [Cu] + 2.15.
    American patent application n ° 2005/006010 presents a method for producing a high strength Al-Zn-Cu-Mg alloy, with better resistance to fatigue crack propagation and high damage tolerance, including stages of foundrying an ingot having the following composition (content by weight): Zn 5.5 to 9.5; Cu 1.5 to 3.5; Mg 1.5 to 3.5; Mn <0.25; Zr <0.25; Cr <0.10; Fe <0.25; If <0.25; Ti <0.10; Hf and / or V <0.25; the other elements being less than 0.05 each and 0.15 in all, the rest being made of aluminum, with homogenization and / or preheating of the ingot after casting, hot working of the ingot and, optionally, cold work hardening to give a wrought product of a thickness greater than 50 mm, heat treatment for dissolving, quenching the product having undergone the heat treatment and artificial aging of the wrought product having undergone the heat treatment, the aging step comprising a first treatment thermal at a temperature between 105 and 135 ° C for more than 2 hours and less than 8 hours, as well as a second heat treatment at a temperature above 135 ° C but below 170 ° C for more than 5 hours and less from 3 p.m. Again, such three-step income is long and difficult to master.
    European patent 1,544,315 presents a laminated, extradited or specially forged product made from an AlZnCuMg alloy with constituents having the following weight content: Zn 6.7 to 7.3; Cu 1.9 to 2.5; Mg 1.0 to 2.0; Zr 0.07 to 0.13; Fe less than 0.15; If less than 0.15; the other elements being less than 0.05 each, and 0.15 in all, the rest being made of aluminum. The product is preferably subjected to a solution treatment, quenching, work hardening and artificial aging.
    US Patent No. 8,277,580 discloses a wrought, laminated or forged aluminum alloy Al-Zn-Cu-Mg product, 2 to 10 inches (5 to 25 cm) thick. This product was subjected to a solution treatment, quenching and tempering. Its breakdown (weight content) is as follows: Zn 6.2 to 7.2; Mg 1.5 to
    2.4; Cu 1.7 to 2.1. Fe 0 to 0.13; If 0 to 0.10; Ti 0 to 0.06; Zr 0.06 to 0.13; Cr 0 to 0.04; Mn 0 to 0.04; impurities and other accessory elements <= 0.05 each.
    U.S. Patent No. 8,673,209 discloses aluminum alloy products less than or equal to 4 inches (10.2 cm) thick, capable of achieving, after being subjected to a solution heat treatment, a quenching and artificial aging, as well as for parts made from these products, an improved combination of strength, fracture toughness and corrosion resistance, the alloy comprising essentially about 6.8 to about 8.5% Zn by weight, about 1.5 to about 2.00% Mg by weight, about 1.75 to about 2.3% Cu by weight, about 0.05 to about 0.3% Zr in weight content, less than about 0.1% Mn in weight content, less than about 0.05% Cr in weight content, the remainder consisting of aluminum, random elements and impurities. It also describes a manufacturing method.
    The effect of the composition of 7XXX alloys on crack resistance by CSG has recently been the subject of a study (NJ Henry Holroyd and GM Scamans, “Stress Corrosion Cracking in Al-Zn-Mg-Cu Aluminum Alloys in Saline Environments "(stress corrosion cracking in a saline environment), Metall. Mater. Trans. A, vol. 44, pages 1230-1253, 2013.). The authors came to the conclusion that the rates of cracking progression by CSG at room temperature for extreme metallurgical and "over-aged" states in saline environment were reduced for Al-Zn-Mg-Cu alloys containing less than 8% Zn in weight content when the Zn / Mg ratios go from 2 to 3, the excess magnesium compared to the stoichiometric levels is less than 1% by weight content and the percentage of copper is less than 0.2% by weight content or will 1.3 to 2% by weight content.
    None of the documents describing the high strength 7xxx alloy products present products having a low sensitivity to FAE under conditions of high stresses and humid environment with at the same time high resistance and high tenacity properties.
    SUMMARY OF THE INVENTION
    One of the objects of the invention was to provide an Al-Zn-Cu-Mg alloy having a specific composition range offering, for wrought products, an improved compromise between mechanical strength for an appropriate level of fracture toughness and resistance to FAE under conditions of high stress and humid environment.
    Another object of the invention was a process for manufacturing wrought aluminum products offering an improved compromise between mechanical strength for an appropriate level of fracture toughness and resistance to FAE under conditions of high stress and of the environment. wet.
    To achieve these and other objectives, the present invention relates to an alloy product based on extruded aluminum, laminated and / or forged with a thickness of at least 25 mm comprising, or advantageously consisting of (percentage by weight content):
    Zn 6.70 - 7.40
    Mg 1.50-1.80
    Cu 2.20 - 2.60, the Cu to Mg ratio being greater than or equal to 1.30
    Zr 0.04-0.14
    Mn 0 - 0.5
    Ti 0-0.15
    V0-0,15
    Cr 0 - 0.25
    Fe 0-0.15
    If 0-0.15 impurities <0.05 each and <0.15 in total.
    The present invention is also directed towards a process for the manufacture of an alloy product based on extruded, rolled and / or forged aluminum, comprising the following steps:
    a) casting an ingot or a billet comprising, or advantageously essentially consisting of (percentage by weight content):
    Zn 6.70 - 7.40
    Mg 1.50 - 1.80
    Cu 2.20 - 2.60, the Cu to Mg ratio being greater than or equal to 1.30
    Zr 0.04-0.14
    Mn 0 - 0.5
    Ti 0-0.15
    V0-0,15
    Cr 0 - 0.25
    Fe 0 - 0.15
    If 0-0.15 impurities <0.05 each and <0.15 in total.
    b) homogenization of the ingot or billet
    c) hot working of said billet or of said homogenized ingot in order to obtain an extruded, rolled and / or forged product with a final thickness of at least 25 mm;
    d) solution treatment and quenching of the product;
    e) traction of the product;
    f) artificial aging.
    BRIEF DESCRIPTION OF THE DRAWINGS
    Figure 1: Relationship between the average number of days of FAE before failure and the yield strength in the short cross direction (TC) for the alloys of the example.
    DETAILED DESCRIPTION
    In the absence of any other indication, everything relating to the chemical composition of the alloys is expressed as a percentage of weight content based on the total weight of the alloy. In the expression Cu / Mg, Cu signifies the weight content of Cu in% and Mg signifies the weight content of Mg in%. The designation of the alloy complies with the regulations of the Aluminum Association, known to those skilled in the art. The definitions of metallurgical states are given in ΓΕΝ 515 (1993).
    Unless otherwise stated, the static mechanical characteristics, i.e. the breaking strength, the elastic limit and the elongation at break are determined by a tensile test in accordance with standard NF EN ISO 6892- 1 (2016), where the parts are removed and their direction is defined in standard EN 485 (2016).
    In the absence of any other specification, the definitions of standard EN 12258 apply.
    The thickness of the extruded products is defined in accordance with standard EN 2066: 2001: the cross section is divided into elementary rectangles of dimensions A and B, A being always the largest dimension of the elementary rectangle and B being considered as the thickness of the elementary rectangle. The lower part is the larger elementary rectangle A.
    The fracture toughness Kæ is determined in accordance with standard ASTM E399 (2012). A curve of the stress intensity as a function of the crack length, known as the curve R, is determined in accordance with standard ASTM E561 (2015). The critical stress intensity factor K c , in other words the intensity factor which makes the crack unstable, is calculated starting from the curve R. The stress intensity factor K C o is also calculated by affecting the length initial crack at the critical load, at the start of the monotonic load. These two values are calculated for a test piece of the required shape. K app designates the factor K C o corresponding to the test piece that was used to test the curve R.
    It should be noted that the width of the test piece used for the toughness test can have a significant influence on the critical stress intensity factor measured during the test. CT specimens were used. Unless stated otherwise, the width W was 5 inches (127 mm) with B = 0.3 inches (7.6 mm) and the initial crack length ao = 1.8 inches (45.7 mm). The measurements were made at mid-thickness.
    Unless otherwise stated, the FAE under conditions of high stresses and humid environment was tested at constant deformation on a tensile sample at mid-thickness, in accordance with what is described in standard ASTM G47 and using a load of '' about 80% of the elastic limit in the TC direction, at a relative humidity of 85% and at a temperature of 70 ° C. The average number of days until failure was calculated from at least 3 test pieces for each heavy plate.
    The term “structural element” is a term well known to those skilled in the art and it refers to a component used in mechanical construction for which the static and / or dynamic mechanical characteristics are of particular importance with regard to the performance of structure and for which a structural calculation is generally prescribed or carried out. These are generally components whose rupture risks seriously compromising the safety of the mechanical engineering, its users or third parties. In the case of an airplane, the structural elements include the fuselage elements (such as the fuselage linings), the spacers, the bulkheads, the circumferential frames, the wing components (such as the wing linings, spacers or stiffeners , ribs, side members), the tail (such as horizontal and vertical stabilizers), floor beams, seat rails and doors.
    The alloy of the invention has a specific composition which makes it possible to obtain products insensitive to FAE under conditions of high stresses and in a humid environment with at the same time a high resistance and high tenacity properties.
    A minimum Zn content of 6.70 and preferably 6.80 or even 6.90 is necessary to obtain sufficient resistance. However, the Zn content should not exceed 7.40 and preferably 7.30 to obtain the desired balance of properties, in particular between toughness and elongation. According to one embodiment, the maximum content of Zn is 7.20.
    A minimum Mg content of 1.50 and preferably 1.55 or even 1.60 is necessary to obtain sufficient strength. However, the Mg content should not exceed 1.80 and preferably 1.75 to obtain the desired balance of properties, in particular between toughness and elongation, as well as to avoid sensitivity to quenching. According to one embodiment, the maximum content of Mg is 1.70.
    According to one embodiment, the Zn content ranges from 6.90 to 7.20% by weight content and the Mg content ranges from 1.60 to 1.70% by weight content.
    A minimum Cu content of 2.20 and preferably 2.25 or 2.30 or even 2.35 is necessary to obtain sufficient resistance and to obtain sufficient performance in terms of FAE. However, the Cu content should not exceed 2.60 and preferably 2.55 in particular to avoid sensitivity to quenching. According to one embodiment, the maximum Cu content is 2.50.
    In order to obtain products with a low sensitivity to AWF under conditions of high stress and humid environment, the Cu / Mg ratio is carefully controlled, to a value of at least 1.30. A minimum Cu / Mg ratio of 1.35 is advantageous, or preferably 1.40. According to one embodiment, the maximum Cu / Mg ratio is equal to
    I, 70 and preferably 1.65.
    A minimum level of solutes (Zn, Mg and Cu) is preferred to obtain the desired resistance. The sum Zn + Cu + Mg is preferably at least 10.7% by weight content and, ideally, at least 11.0% by weight content, or even at least
    II, 1% by weight content. Likewise, Cu + Mg is preferably at least 3.8% by weight content and, ideally, at least 3.9% by weight content. According to one embodiment, Zn + Cu + Mg is at least 11.2% by weight content and Cu + Mg at least 4.0% by weight content.
    A high content of Mg and Cu can increase the sensitivity to quenching and affect the toughness performance at break. Preferably, the combined content of Mg and Cu should be kept below 4.3% in weighted content and, ideally, below 4.2% in weighted content.
    The Zn / Mg ratios of the products of the invention range from 3.7 to 4.9, which is surprising in the light of what is exposed by Holroyd Scamans, namely from 2 to 3. Preferably, the Zn ratios / Mg of the products of the invention range from 4.0 to 4.6.
    The alloys of the present invention also contain 0.04 to 0.14% of zirconium in weighted content, which is generally used to regulate the grain size. It is advised that the Zr content is preferably about 0.07% by weight and ideally about 0.09% in order to affect the recrystallization, but it is advantageous if it remains lower at about 0.12% by weight content in order to reduce the casting problems.
    It is generally possible to add titanium if desired during casting, in combination with boron or carbon, in order to limit the size of the grains on the raw foundry product. The present invention can typically accommodate a Ti content by weight of about 0.06% or about 0.05%. In a preferred embodiment of the invention, the weight content of Ti is from about 0.02% to about 0.06% and, ideally, from about 0.03% to about 0.05%.
    It is possible to add manganese up to about 0.5% by weight content. According to one embodiment, the weight content of Mn is 0.2 to 0.5%. However, manganese is preferably avoided and it is generally kept below about 0.04% by weight content and preferably below about 0.03% by weight content.
    It is possible to add vanadium up to about 0.15% by weight content. According to one embodiment, the content by weight of V is from 0.05 to 0.15%. However, vanadium is preferably avoided and is generally kept below about 0.04% by weight content and, preferably, below about 0.03% by weight content.
    It is possible to add chromium up to about 0.25% by weight content. According to one embodiment, the weight content of Cr is from 0.15 to 0.25%. Preferably, however, chromium is avoided and it is generally kept below about 0.04% by weight content and, preferably, below about 0.03% by weight content.
    The present alloy may also contain other elements to a lesser extent and in certain embodiments, on a less preferential basis, however. Generally, iron and silicon have an effect on the fracture toughness properties. The iron and silicon content should generally be kept low, with a weight content of at most 0.15% and, preferably, not exceeding about 0.13% by weight, or even ideally about 0 , 10% by weight content for iron and, preferably, not exceeding about 0.10% by weight content, or even ideally 0.08% by weight content for silicon. In one embodiment of the present invention, the content of iron and silicon is <0.07 by weight content.
    The other elements are impurities which should have a maximum weight content of 0.05% each and <0.15 in total, preferably a maximum weight content of 0.03% each and <0.10 in total .
    A suitable method of manufacturing wrought products according to the present invention comprises: (i) casting an ingot or billet of alloy according to the present invention; (ii) carrying out a homogenization of the ingot or the billet, preferably with at least one step at a temperature of about 460 ° C to about 510 ° C or, ideally, from about 470 ° C to about 500 ° C as a rule for 5 to 30 hours; (iii) carrying out a hot working of said billet or of said homogenized ingot, in one or more passes by extrusion, rolling and / or forging, with an inlet temperature preferably between approximately 380 ° C. and 460 ° C approximately, ideally between approximately 400 ° C and approximately 450 ° C, in order to obtain an extruded, rolled and / or forged product with a final thickness of at least 25 mm; (iv) carrying out a solution treatment, preferably at a temperature of 460 ° C to approximately 510 ° C or, ideally, from approximately 470 ° C to approximately 500 ° C as a general rule for 1 to 10 hours depending on thickness; (v) carrying out a quenching, ideally with water at room temperature; (vi) achieving a relaxation of stresses by controlled traction or compression with a permanent deformation preferably less than 5%, ideally from 1 to 4%; and (vii) carrying out an artificial aging treatment.
    The present invention finds particular utility in calibers of thickness greater than about 25 mm. In a preferred embodiment of the invention, a wrought product of the present invention is a heavy plate with a thickness ranging from 25 to 200 mm, or advantageously from 50 to 150 mm, comprising an alloy according to the present invention. The "over-aged" metallurgical states ("type T7") are advantageously used to improve the corrosion resistance in the context of the present invention. The metallurgical states which can be used for the products of the invention include for example T6, T651, T73, T74, T76, T77, T7351, T7451, T7452, T7651, T7652 or T7751, the metallurgical states T7351, T7451 and T7651 being preferred. A tempering treatment is advantageously carried out in two stages, at the rate of a first stage of between 110 ° C. and 130 ° C. for 3 to 20 hours, preferably for 5 to 12 hours, and a second stage at a temperature between 140 ° C and 170 ° C, preferably between 150 ° C and 165 ° C, for 5 to 30 hours.
    According to an advantageous embodiment, the equivalent tempering time t (eq) at 155 ° C is between 8 and 30 hours and, ideally, between 12 and 25 hours.
    The equivalent time t (eq) at 155 ° C being defined by the formula:
    Jexp (-16000 / T) dt exp (-16000 / T re f) where T is the instantaneous temperature in ° K during annealing, T re f is a reference temperature taken at 155 ° C (428 K) and t ( éq) is expressed in hours.
    The narrow range of composition of the alloy of the invention, selected mainly to make a compromise between resistance and toughness, has, against all expectations, given products wrought with high performances of FAE under conditions of high stresses and d humid environment.
    Thus, a product in accordance with the invention preferably has the following properties:
    a) a minimum service life without rupture after cracking assisted by the environment (FAE) under conditions of high stresses, for a level of stress in the short cross direction (TC) of 80% of the apparent elastic limit of produced in the TC direction, and a humid environment with 85% relative humidity at a temperature of 70 ° C for at least 40 days;
    b) an apparent limit of conventional elasticity measured in the direction L at a quarter of the thickness of at least 515 - 0.279 * t MPa and, preferably, of 525 0.279 * t MPa, or even of 535 - 0.279 * t MPa (t being the thickness of the product in mm);
    c) a toughness Kæ in the direction LT, measured at a quarter of the thickness of at least 42 - 0.11 MPa ^ m and, preferably, 44-0.1 t MPa ^ m or even 47 - 0.1 t MPa ^ m (t being the thickness of the product in mm).
    Preferably the minimum lifespan without rupture after cracking assisted by the environment (FAE) under said conditions of high stresses and humid environment is at least 50 years, even at least 70 years and, ideally, d '' at least 90 days in a short cross direction (TC).
    According to one embodiment, the high stress conditions include a short transverse stress (TC) level of 380 MPa.
    The wrought products of the present invention are advantageously used or incorporated into structural elements for the construction of aircraft.
    According to an advantageous embodiment, the products of the invention are used in the wing ribs, side members and chassis. In certain embodiments of the invention, the wrought products of the present invention are welded to other wrought products to form wing ribs, side members and chassis.
    These, as well as other aspects of the present invention, are explained in more detail with respect to the following illustrated and nonlimiting examples.
    EXAMPLE
    Five ingots were poured, one from a product according to the invention (E) and four reference examples with the following composition (Table 1):
    Table 1: composition (weight content in%) of casting according to the invention and of reference casting.
    Alloy Yes Fe Cu mg Zn Ti Zr AT 0.044 0.073 1.93 2.16 8.45 0,017 0.11 B 0,037 0.066 1.59 1.85 6.34 0,037 0.11 VS 0,029 0.03 2.11 1.69 7.24 0.041 0.1 D 0,035 0,052 2.14 1.66 7.20 0.03 0.1 E 0,035 0.053 2.22 1.66 7.18 0,035 0.1
    The ingots were then scalped and were homogenized at 473 ° C (alloy A) or
    479 ° C (alloys B to E). The ingots have been hot rolled to form a strong sheet with a thickness of 120 mm (alloy A) or 76 mm (alloys B to E). The hot rolling inlet temperature was between 420 ° C and 440 ° C. The plates have undergone a heat treatment in solution at a wet temperature of 473 ° C (alloy A) or 479 ° C (alloys B to E). The plates were quenched and put in tension with a permanent elongation of between 2.0% and 2.5%.
    The plates were subjected to a 6-hour tempering in two stages at 120 ° C, followed by approximately 10 hours at 160 ° C (alloy A), or approximately 15 hours at 155 ° C (alloys B to E) , for a total equivalent time of 17 hours at 155 ° C to obtain a metallurgical state T7651.
    All the samples tested were essentially non-recrystallized, with a volume fraction of recrystallized grains less than 35%.
    The samples were tested mechanically at a quarter of the thickness in the L and TL directions and at mid-thickness for the TC direction to determine their static mechanical properties as well as their toughness at break. The apparent yield strength, the breaking strength and the elongation at break are given in Table 2.
    Table 2: Static mechanical properties of the samples
    SAMPLESnot Direction L Direction TL TC Direction Breaking strength (MPa) Yield strength (MPa) E(%) Breaking strength (MPa) Yield strength (MPa) E(%) Breaking strength (MPa) Yield strength (MPa) E(%) AT 562 524 9.1 558 513 4.8 530 four hundred ninety seven 0.6 B 513 489 16.3 538 488 13.0 522 456 8.5 VS 547 519 14.0 552 509 14.0 539 480 6.8 D 548 517 15.0 544 503 14.0 531 473 8.5 E 551 522 15.0 552 509 13.0 539 476 oo00
    The sample according to the invention has a resistance similar to that of Comparative Examples A, C and D. Compared to alloy B, the improvement is greater than 5%. Compared to the 7050 plates, the improvement in the apparent elastic limit in the direction L is greater than 10%.
    The results of the fracture toughness tests are given in Table 3.
    Table 3: Properties of fracture toughness of samples
    Sample K 1C Kapp L-T(MPAV / m) T-L(MPaVrn) S-L(MPAV / m) L-T(MPAV / m) T-L(MPAV / m) AT 29.5 22.8 22.6 B 44.0 34.4 30.7 VS 43.2 37.6 42.0 95.7 67.7 D 44.2 36.9 38.0 95.5 71.3 E 43.0 34.0 35.8 114.7 62.5
    The FAE under conditions of high stresses and humid environment was measured with tensile specimens in the direction TC described in standard ASTM G47. The stresses and the test environment were different from standard ASTM G47 and the load used was approximately 80% of the elastic limit in the direction TC at t / 2, under a relative humidity of 85 % and at a temperature of 70 ° C. The average number of days until failure was calculated from 3 test pieces for each heavy plate, except for the A test carried out at 407 MPa (in which the 6 test pieces were tested at constant deformation and at constant load ).
    The results are presented in Table 4.
    Table 4 Results of AWF under conditions of high stress and humid environment
    Alloy and metallurgical condition Thickness r (mm) Elastic limit TC t / 2(MPa) ConstraintFAE (MPa) Test method Number of average days until break A-T76 120 four hundred ninety seven 384 Constant deformation 10 four hundred ninety seven 407 Constant deformation 13 four hundred ninety seven 407 Constant stress 14 B-T76 76 456 365 Constant deformation 24 C-T76 76 480 384 Constant deformation 34 D-T76 76 473 378 Constant deformation 29 E-T76 76 476 381 Constant deformation 100
    Against all expectations, the resistance to FAE under conditions of high stress and humid environment for the heavy sheet of alloy E (according to the invention) in the short cross direction was high, with an improvement greater than 60 days compared to the reference examples (C and D) for practically the same limit value
    FAE under conditions of high stress and humid environment compared to what the prior art knew. It was particularly impressive and unexpected to see a heavy plate in accordance with the present invention exhibit a higher level of resistance to FAE, at the same time a tensile strength and a toughness at break comparable to the samples according to the previous state. of technique.
    In the present text and the claims which follow, articles such as "le / la", "un / une" have a generic value which can either designate the singular or the plural.
    权利要求:
    Claims (10)
    [1" id="c-fr-0001]
    1. Product in an alloy based on extruded aluminum, laminated and / or forged with a thickness of at least 25 mm comprising, or advantageously consisting of (percentage by weight content):
    Zn 6.70 - 7.40
    Mg 1.50-1.80
    Cu 2.20 - 2.60, the Cu to Mg ratio being greater than or equal to 1.30
    Zr 0.04-0.14
    Mn 0 - 0.5
    Ti 0-0.15
    V0-0,15
    Cr 0 - 0.25
    Fe 0-0.15
    If 0-0.15 impurities <0.05 each and <0.15 in total.
    [2" id="c-fr-0002]
    2. Product according to claim 1, in which Cu ranges from 2.35 to 2.50.
    [3" id="c-fr-0003]
    3. Product according to any one of claims 1 to 2, in which Cu / Mg ranges from 1.35 to 1.65.
    [4" id="c-fr-0004]
    4. Product according to any one of claims 1 to 3, wherein Zn / Mg ranges from 4.0 to 4.6.
    [5" id="c-fr-0005]
    5. Product according to any one of claims 1 to 4, in which Cu + Mg is at least 3.8% by weight content, ideally at least 3.9% by weight content.
    [6" id="c-fr-0006]
    6. Product according to any one of claims 1 to 5, wherein said product has the following properties:
    a) a minimum service life without rupture after cracking assisted by the environment (FAE) under conditions of high stresses, for a level of stress in the short cross direction (TC) of 80% of the apparent elastic limit of produced in the TC direction, and a humid environment with 85% relative humidity at a temperature of 70 ° C for at least 40 days;
    b) an apparent limit of conventional elasticity measured in the direction L at a quarter of the thickness of at least 515 - 0.279 * t MPa and, preferably, of 525 0.279 * t MPa, or even of 535 - 0.279 * t MPa (t being the thickness of the product in mm);
    c) a toughness Kæ in the direction LT, measured at a quarter of the thickness of at least 42 - 0.1 lt MPaVm and, preferably, 44 - 0.1 t MPaNm or even 47-0.1 t MPa ^ / m (t being the thickness of the product in mm).
    [7" id="c-fr-0007]
    7. Product according to any one of claims 1 to 6, the thickness of which ranges from 50 to 150 mm.
    [8" id="c-fr-0008]
    8. Structural element suitable for aeronautical construction and used for the manufacture of wing ribs, side members and chassis, comprising a product according to any one of claims 1 to 7.
    [9" id="c-fr-0009]
    9. A method of manufacturing an extruded, rolled and / or forged product from an aluminum-based alloy comprising the following steps:
    a) casting an ingot comprising, or advantageously essentially consisting of (percentage by weight content):
    Zn 6.70 - 7.40
    Mg 1.50-1.80
    Cu 2.20 - 2.60, the Cu to Mg ratio being greater than or equal to 1.30
    Zr 0.04-0.14
    Mn 0 - 0.5
    Ti 0-0.15
    V0-0,15
    Cr 0 - 0.25
    Fe 0-0.15
    If 0-0.15 impurities <0.05 each and <0.15 in total
    b) homogenization of the ingot or billet
    c) hot working of said billet or of said homogenized ingot in order to obtain an extruded, rolled and / or forged product with a final thickness of at least 25 mm;
    d) solution treatment and quenching of the product;
    e) traction of the product;
    f) artificial aging.
    [10" id="c-fr-0010]
    10. The method of claim 9 wherein the duration of equivalent income t (eq) is between 8 and 30 hours and, ideally, between 12 and 25 hours, the equivalent time t (eq) at 155 ° C being defined by the formula :
    fexp (-16000 / T) dt exp (-16000 / T re f) where T is the instantaneous temperature in ° K during annealing, T ref is a reference temperature taken at 155 ° C (428 K) and t (éq ) is expressed in hours.
    类似技术:
    公开号 | 公开日 | 专利标题
    FR3068370B1|2019-08-02|AL-ZN-CU-MG ALLOYS AND PROCESS FOR PRODUCING THE SAME
    EP1544315B1|2012-08-22|Wrought product in the form of a rolled plate and structural part for aircraft in Al-Zn-Cu-Mg alloy
    CA2931303C|2021-10-26|Aluminum/copper/lithium alloy material for underwing element having enhanced properties
    EP2364378B1|2014-01-08|Products in aluminium-copper-lithium alloy
    EP3384061B1|2020-02-05|Aluminium-copper-lithium alloy having improved mechanical strength and improved toughness
    FR2853667A1|2004-10-15|IMPROVED AL-AN-MG-CU ALLOY AS REGARDS ITS COMBINED PROPERTIES OF DAMAGE TOLERANCE AND MECHANICAL STRENGTH
    CA2798480C|2018-01-16|Aluminum-copper-lithium alloy for lower surface element
    CA2907854C|2021-07-13|Thin sheets made of an aluminium-copper-lithium alloy for producing airplane fuselages
    EP3201372B1|2021-01-27|Isotropic sheets of aluminium-copper-lithium alloys for the fabrication of fuselages of aircrafts and method of manuacturing same
    CA2907807A1|2014-10-09|Aluminium-copper-lithium alloy sheets for producing aeroplane fuselages
    CA2960942A1|2016-04-07|Wrought product made of a magnesium-lithium-aluminum alloy
    CA3085811A1|2019-06-27|Improved process for manufacturing sheets made of aluminium-copper-lithium alloy for aircraft fuselage manufacture
    WO2018073533A1|2018-04-26|Thin sheets made of an aluminium-magnesium-scandium alloy for aerospace applications
    FR3071513A1|2019-03-29|HIGH RESISTANCE AL-ZN-CU-MG ALLOYS AND PROCESS FOR PRODUCING THE SAME
    FR3080860A1|2019-11-08|LITHIUM COPPER ALUMINUM ALLOY WITH ENHANCED COMPRESSION RESISTANCE AND TENACITY
    CA3058021A1|2018-10-18|Aluminium-copper-lithium alloy products
    CA3001519A1|2017-04-20|Thin sheets made from aluminium-magnesium-zirconium alloys for aerospace applications
    FR3067044B1|2019-06-28|ALUMINUM ALLOY COMPRISING LITHIUM WITH IMPROVED FATIGUE PROPERTIES
    FR3080861A1|2019-11-08|METHOD FOR MANUFACTURING LITHIUM COPPER ALUMINUM ALLOY WITH IMPROVED RESISTANCE AND TENABILITY
    FR3104172A1|2021-06-11|Improved toughness aluminum-copper-lithium alloy thin sheets and manufacturing process
    同族专利:
    公开号 | 公开日
    FR3068370B1|2019-08-02|
    WO2019007817A1|2019-01-10|
    JP2020525649A|2020-08-27|
    CA3067484A1|2019-01-10|
    EP3649268A1|2020-05-13|
    US20200131612A1|2020-04-30|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP0589807A1|1992-09-22|1994-03-30|Société Métallurgique de Gerzat|Aluminium alloy for pressurised hollow bodies|
    US6972110B2|2000-12-21|2005-12-06|Alcoa Inc.|Aluminum alloy products having improved property combinations and method for artificially aging same|
    FR2853666A1|2003-04-10|2004-10-15|Corus Aluminium Walzprod Gmbh|HIGH-STRENGTH Al-Zn ALLOY, PROCESS FOR PRODUCING PRODUCTS IN SUCH AN ALLOY, AND PRODUCTS OBTAINED ACCORDING TO THIS PROCESS|
    US5312498A|1992-08-13|1994-05-17|Reynolds Metals Company|Method of producing an aluminum-zinc-magnesium-copper alloy having improved exfoliation resistance and fracture toughness|
    FR2716896B1|1994-03-02|1996-04-26|Pechiney Recherche|Alloy 7000 with high mechanical resistance and process for obtaining it.|
    US5865911A|1995-05-26|1999-02-02|Aluminum Company Of America|Aluminum alloy products suited for commercial jet aircraft wing members|
    US6027582A|1996-01-25|2000-02-22|Pechiney Rhenalu|Thick alZnMgCu alloy products with improved properties|
    US20050006010A1|2002-06-24|2005-01-13|Rinze Benedictus|Method for producing a high strength Al-Zn-Mg-Cu alloy|
    EP1544315B1|2003-12-16|2012-08-22|Constellium France|Wrought product in the form of a rolled plate and structural part for aircraft in Al-Zn-Cu-Mg alloy|
    CN103834837B|2005-02-10|2016-11-09|肯联铝业轧制品-雷文斯伍德有限公司|Al-Zn-Cu-Mg acieral and manufacture method thereof and purposes|
    US8673209B2|2007-05-14|2014-03-18|Alcoa Inc.|Aluminum alloy products having improved property combinations and method for artificially aging same|US10835942B2|2016-08-26|2020-11-17|Shape Corp.|Warm forming process and apparatus for transverse bending of an extruded aluminum beam to warm form a vehicle structural component|
    MX2019004494A|2016-10-24|2019-12-18|Shape Corp|Multi-stage aluminum alloy forming and thermal processing method for the production of vehicle components.|
    CN111020252B|2019-12-30|2021-02-02|绵阳市天铭机械有限公司|Processing technology of aluminum alloy plate|
    CN111575618B|2020-05-15|2021-07-02|江苏理工学院|Treatment method for reducing cracking tendency of large-deformation rolling Al-Zn alloy|
    CN111876639A|2020-08-06|2020-11-03|北部湾大学|7000 series aluminum alloy for automobile upright column and manufacturing method of plate thereof|
    法律状态:
    2019-01-04| PLSC| Search report ready|Effective date: 20190104 |
    2019-07-25| PLFP| Fee payment|Year of fee payment: 3 |
    2020-07-27| PLFP| Fee payment|Year of fee payment: 4 |
    2021-07-27| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1756275A|FR3068370B1|2017-07-03|2017-07-03|AL-ZN-CU-MG ALLOYS AND PROCESS FOR PRODUCING THE SAME|
    FR1756275|2017-07-03|FR1756275A| FR3068370B1|2017-07-03|2017-07-03|AL-ZN-CU-MG ALLOYS AND PROCESS FOR PRODUCING THE SAME|
    US16/627,970| US20200131612A1|2017-07-03|2018-06-28|Al-zn-cu-mg alloys and their manufacturing process|
    JP2019572491A| JP2020525649A|2017-07-03|2018-06-28|Al-Zn-Cu-Mg alloy and methods for producing the same|
    PCT/EP2018/067492| WO2019007817A1|2017-07-03|2018-06-28|Al- zn-cu-mg alloys and their manufacturing process|
    CA3067484A| CA3067484A1|2017-07-03|2018-06-28|Al- zn-cu-mg alloys and their manufacturing process|
    EP18736857.6A| EP3649268A1|2017-07-03|2018-06-28|Al- zn-cu-mg alloys and their manufacturing process|
    [返回顶部]