EP2274454B1 - Legierungszusammensetzung und herstellungsverfahren dafür - Google Patents

Legierungszusammensetzung und herstellungsverfahren dafür Download PDF

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EP2274454B1
EP2274454B1 EP08738391.5A EP08738391A EP2274454B1 EP 2274454 B1 EP2274454 B1 EP 2274454B1 EP 08738391 A EP08738391 A EP 08738391A EP 2274454 B1 EP2274454 B1 EP 2274454B1
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alloy
followed
temperature
billet
aluminium
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EP2274454A1 (de
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Kumar Ashim Mukhopadhyay
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Director General Defence Research & Development Organisation
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C21/00Alloys based on aluminium
    • C22C21/10Alloys based on aluminium with zinc as the next major constituent
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22FCHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/053Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with zinc as the next major constituent

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  • the present invention provides an Aluminium-Zinc-Magnesium-Copper-Zirconium alloy extrusion and a process for preparing an Aluminium-Zinc-Magnesium-Copper-Zirconium alloy extrusion.
  • Aluminum-Zinc-Magnesium-Copper-Zirconium (Al-Zn-Mg-Cu-Zr) alloys are in great demand for various strength critical applications in areas of aerospace and defence. These alloys are commonly processed in the form of sheets, plates, extrusion, forgings, etc. for various structural applications. In aerospace applications, one of the requirements is the processing of these alloys in the form of thin sheets having thickness ⁇ 0.3 mm, wherein the thin sheets of Al alloys are used in combination with fibres (preferably glass fibres) to form fibre-metal laminated (FML) composites.
  • fibres preferably glass fibres
  • the strength properties of the thin sheets of Al alloys used in the FML composites play an important role in deciding the tensile yield strength of the FML composites [ Ad Viot and J.W. Gunnink, Fibre Metal Laminates: An Introduction, Kluwer Academic Publishers, The Netherlands, 2001 ]. Further, Al alloy sheets having thickness of ⁇ 0.3 mm are preferred for this purpose because it improves drapability.
  • U.S. Pat. No. 4,477,292 and 4,832,758 discloses Aluminium-Zinc-Magnesium-Copper-Zirconium (Al-Zn-Mg-Cu-Zr) alloys as a class of very high strength aluminium alloy that can be produced via ingot metallurgical route.
  • Al-Zn-Mg-Cu-Zr Aluminium-Zinc-Magnesium-Copper-Zirconium
  • U.S. Pat. Nos. 4,699,673 ; 4,988,394 and U.S. Patent application No.20060191609 disclose the methods of preparation of thin sheets of Al-Zn-Mg-Cu-Zr alloys having thickness up to 1.2 mm. But there is no information regarding the preparation of high strength Al-Zn-Mg-Cu-Zr sheets having thickness as low as ⁇ 0.3 mm. The problem associated with the retention of high strength in such products is the onset of recrystallization resulting in cracking that becomes more pronounced as the sheets are progressively made thinner. However, due to the proprietary nature of the processing details of such thin sheets, there is no information on this topic in the literature.
  • Al-Zn-Mg-Cu-Zr alloy i.e. AA 7055
  • Aluminium Company of America, (ALCOA) Technical Data available at www.millproducts-alcoa.com] has the composition of Al-(7.6-8.4) wt% Zn-(1.8-2.3) wt% Mg-(2-2.6) wt% Cu-(0.08-0.25) wt% Zr.
  • the T77 temper possesses strength properties that correspond to the peak aged, T6 temper, but stress corrosion cracking resistance similar to the T76 temper [ ALCOA publication. Light Metal Age, October, 1991, p. 14 ].
  • US Patent Application 20040099352 discloses another high strength Al-Zn-Mg-Cu-Zr alloy comprising (in wt%) of 8.2-10%Zn, 1.95-2.5%Cu, 1.9-2.5%Mg, 0.05-0.25 % Zr.
  • the alloy when produced by extrusion processing and peak aged gives rise to 0.2 % P.S. of 703 MPa.
  • Another high strength, Al-Zn-Mg-Cu-Zr base alloy containing scandium, processed in the form of extrusions and heat treated to the peak aged T6 temper have the composition of Al-8.6Zn-2.6Mg-2.4Cu-0.2 wt% Sc and an undisclosed amount of Zr [ Metall. Mater. Trans. A, 30A, 1017, 1999 ].
  • US Patent Application 20050056353 discloses another high strength Al-Zn-Mg-Cu-Zr-Sc alloy comprising (in wt%) of 8.5-11 %Zn, 1.8-2.4%Mg, 1.8-2.6%Cu, 0.05-0.30%Sc and at least one element from the group Zr, V and Hf not exceeding 0.5wt%.
  • the alloy when produced by extrusion processing and peak aged gives rise to 0.2% P.S. values that range from 670 to 715 MPa.
  • US Patent Application 20050072497 discloses yet another high strength Al-Zn-Mg-Cu-Zr alloy comprising (in wt%) of 8.3-14%Zn, 0.3-2%Cu, 0.5-4.5%Mg, 0.03-0.15%Zr and at least one element from the group Sc, Hf, La, Ce, Nd [the amount of the selected element ranging between 0.02 and 0.7wt%].
  • the alloy when produced by extrusion processing and peak aged showed 0.2%P.S. values ranging from 670 to 783 MPa.
  • a major drawback of the Sc-bearing alloys is that scandium metal is expensive. Yet another limitation of the abovementioned alloys is that scandium ores are not available in many countries including India. Recent revelations are that the fatigue properties are deteriorated by the presence of Sc in Al-Zn-Mg-Cu-Zr alloys [ Scripta Materialia, Vol.52, p. 645, 2005 ].
  • Aluminium-Zinc-Magnesium-Copper-Zirconium (Al-Zn-Mg-Cu-Zr) alloy having significantly high strength that have a variety of applications especially in the field of aerospace applications, wherein sheets of thickness even less than 0.30 mm are needed, and in the filed of defence applications, extrusions of various dimensions are utilized for a number of applications.
  • the present invention provides an Aluminium-Zinc-Magnesium-Copper-Zirconium alloy extrusion according to claim 1 and a process for preparing an Aluminium-Zinc-Magnesium-Copper-Zirconium alloy extrusion according to claim 2.
  • This disclosure provides an Aluminum-Zinc-Magnesium-Copper-Zirconium alloy of composition Al-(8-12.5)wt%Zn-(1.2-2.0)wt%Mg-(1.4-2.2)wt%Cu-(0.10-0.18)wt%Zr and method of its preparation.
  • the disclosure not being part of the invention, also provides a method for preparing alloy semi-products of this composition that can be further processed into significantly high strength alloy extrusions or alloy thin sheets.
  • One aspect of the present disclosure provides a process for the preparation of an Al-Zn-Mg-Cu-Zr alloy using two-step homogenization process so as to cause more effective dissolution of the solidification products, thereby enabling the alloy to retain increased solute supersaturation during subsequent thermal and mechanical processing and to obtain high strength upon aging.
  • Another aspect of the present disclosure provides a process of preparation of Al-Zn-Mg-Cu-Zr alloy extrusions using optimized alloy composition and extrusion processing parameters so as to enable the alloy to obtain high strength through retaining essentially unrecrystallized grain structure and imparting solutionising effect during extrusion processing.
  • Another aspect of the present disclosure provides a process of preparation of an Al-Zn-Mg-Cu-Zr alloy thin sheets using optimized alloy composition, homogenization treatment, rolling parameters and intermediate annealing treatments so as to enable the alloy to greatly minimize the extent of edge cracking and to obtain high strength through the retention of essentially unrecrystallized grain structure in most parts of the sheets.
  • Yet another aspect of the present disclosure provides a process of preparation of an Al-Zn-Mg-Cu-Zr alloy using two-step artificial aging treatment so as to enable the alloy to obtain reproducible strength properties.
  • Yet another aspect of the present disclosure provides a process for preparation of less than 0.30 mm thick Al-Zn-Mg-Cu-Zr alloy sheets having significantly high strength.
  • Al-Zn-Mg-Cu-Zr Aluminium-Zinc-Magnesium-Copper-Zirconium
  • Al-Zn-Mg-Cu-Zr Aluminium-Zinc-Magnesium-Copper-Zirconium
  • Al-Zn-Mg-Cu-Zr Aluminium-Zinc-Magnesium-Copper-Zirconium
  • Al-Zinc-Magnesium-Copper-Zirconium (Al-Zn-Mg-Cu-Zr) alloy thin sheet of composition (in weight %):
  • the process comprising:
  • One aspect of the present disclosure provides a process for preparing Aluminium-Zinc-Magnesium-Copper-Zirconium (Al-Zn-Mg-Cu-Zr) alloy semi-products wherein the primary aluminium has a minimum purity of 99.80 wt%.
  • Another aspect of the present disclosure provides a process for preparing Al-Zn-Mg-Cu-Zr alloy semi-product wherein a charge mixture comprising of 76.38 to 84.81% by weight of primary aluminium and 4.54 to 6.97% by weight of the master alloy Al-33wt%Cu is melted in an induction furnace by melting at a temperature in the range of 720 to 730°C.
  • Another aspect of the present disclosure provides a process for preparing Al-Zn-Mg-Cu-Zr alloy semi-product wherein elemental pure Zn in the range of 8.15 to 12.65% by weight is added to the molten charge and the temperature of the charge is raised in the range of 735 to 745°C. Subsequently, 2.04 to 3.32% by weight of Al-50wt%Mg master alloy and 0.46 to 0.68% by weight of Mg-28wt%Zr master alloy are added and the molten alloy is superheated to a temperature in the range of 755 to 765°C for 10 to 15 minutes.
  • An aspect of the present disclosure provides a process for preparing Al-Zn-Mg-Cu-Zr alloy semi-product wherein the melt, at a reduced temperature in the range of 710 to720°C, is poured under argon atmosphere into a metallic mould of suitable size preheated to a temperature in the range of 145 to 155°C.
  • Another aspect of the present disclosure provides a process for preparing Al-Zn-Mg-Cu-Zr alloy semi-product wherein the melt is solidified to obtain an as-cast billet or slab of alloy.
  • alloy semi-product refers to as cast billets and as-cast slabs of the alloy.
  • One aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions, said process comprising of:
  • Another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions of composition Al-(11.5-12.5)wt%Zn-(1.3-2.0)wt%Mg-(1.5-2.2) wt%Cu-(0.16-0.18)wt%Zr, said process comprising of:
  • Another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions wherein homogenization is carried out in two steps.
  • the first step is carried out at a temperature in the range of 440 to 450°C for 25 to 35 h followed by a second step homogenization at a temperature in the range of 450 to 460°C for 20 to 30 h followed by cooling in air.
  • the homogenization treatment eliminates dendritic segregation in the cast microstructure and causes more effective dissolution of the solidification products, thereby enabling the alloy to retain increased solute supersaturation during subsequent thermal and mechanical processing so as to obtain high strength upon aging.
  • the homogenized billets are scalped to remove the oxide layers formed on the surfaces.
  • the scalped billets are subjected to non-destructive testing to detect casting defects.
  • Further aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions wherein the extrusion processing of the billets is carried out at an initial billet temperature in the range of 400 to 430°C; extrusion ratio in the range of 15:1 to 25:1 and a ram speed of 2-5 mm/s.
  • One aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions wherein solution treatment is carried out at a temperature in the range of 450 to 460°C for 1 to 2 h followed by water quenching at room temperature.
  • the extrusions are subjected to stretching to obtain 1 to 1.5% permanent set for stress relieving purpose.
  • Another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions wherein the stretched alloy extrusions are subjected to two-step artificial aging at 90 to 100°C for 6 to 8 h in the first stage followed by a second stage aging in the temperature range of 120 to 125°C for 20 to 25 h. This treatment produces peak strength in the alloy extrusion in a reproducible manner.
  • Yet another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions using optimized extrusion processing parameters so as to enable the alloy to obtain high strength the alloy through retaining essentially unrecrystallized grain structure and imparting solutionising effect during extrusion processing.
  • Further aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy extrusions having minimum 0.2% tensile P.S. of 750 MPa.
  • An aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy thin sheets, said process comprising of:
  • Another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy thin sheets of composition Al-(8-10)wt%Zn-(1.2-2.0)wt%Mg-(1.4-2.2) wt%Cu-(0.12-0.18)Zr, said process comprising of:
  • Another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy thin sheets wherein the homogenization treatment of the as-cast slabs of the alloy is carried out at a temperature in the range of 445 to 455°C for 25 to35 h in the first step followed by a second step homogenization at a temperature in the t range of 455 to 465°C for 10 to 20 h followed by cooling in air.
  • the homogenization treatment eliminates dendritic segregation in the cast structure.
  • the homogenized slabs are scalped to remove the oxide layers formed on the surfaces. The scalped slabs are then subjected to the non-destructive testing to detect casting defects.
  • Yet another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy thin sheets wherein the scalped slabs (having an initial thickness of 100 mm) are subjected to hot rolling at an initial billet temperature in the range of 425 to 435°C and at a linear speed of 20 m/minute to produce plates having thickness of around 22 mm. These plates are then cross-rolled using the same initial billet temperature and rolling speed to finally produce sheets having thickness of about 5 mm.
  • hot rolling 4 to 8% reduction in the thickness of the billet in three passes followed by intermediate annealing at the temperature in the range of 415 to 435°C for 15 to 25 minutes. This cycle is continued till such time the targeted plate thickness of 22 mm and subsequently the sheet thickness of 5 mm is obtained.
  • the intermediate annealing treatment is given for stress relief purposes.
  • FIG. 1 provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy thin sheets wherein the hot rolled sheets are subjected to cold rolling at room temperature in steps such that each step involves 15 to 25% reduction in thickness in three passes and subsequent intermediate annealing at the temperature in the range of 415 to 425°C for 15 to 25 minutes followed by cooling in air.
  • the intermediate annealing treatment is given for stress relief purpose.
  • the process of cold rolling and subsequent intermediate annealing is repeated till the thickness of the sheet is reduced to 0.28 mm i.e. below 0.3 mm.
  • An aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy thin sheets wherein solution treatment of rolled sheets is carried out at a temperature range in the range of 450 to 460°C for 1 to 1.5 h followed by water quenching at room temperature.
  • Another aspect of the present disclosure provides a process for preparing high strength Al-Zn-Mg-Cu-Zr alloy thin sheets wherein artificial aging is a two-step process carried out at a temperature in the range of 90 to 100°C for 6 to 8 h followed by aging at a temperature in the range of 115 to 125°C for 20 to 30 h. This treatment produces peak strength in the alloy.
  • One aspect of the present disclosure is to provide a process for the preparation of high strength Al-Zn-Mg-Cu-Zr alloy in the form of sheets of thickness less than 0.3 mm having high, reproducible strength properties i.e. a minimum 0.2% tensile PS of 623 MPa in the peak aged temper.
  • Example 1 Preparation of Al-11.8 wt% Zn-1.4 wt% Mg-1.8 wt% Cu-0.16 wt% Zr
  • the charge was superheated to 760°C and the whole material was held at this temperature for 10 minutes.
  • the temperature was then reduced to 740°C and 0.03 kg of nucleant pellets were added for grain refinement purpose.
  • 0.04 kg of degasser pellets were added for degassing purpose.
  • the molten alloy, at a temperature of 720°C, was then poured under argon atmosphere into a preheated (to the temperature of 150°C) metallic mould of suitable size.
  • a cylindrical as-cast billet of 95 mm diameter and 250 mm height was obtained.
  • the billet was subjected to two-step homogenization treatment comprising of 24 h at 445°C followed by 24 h at 455°C followed by cooling in air.
  • the billet was scalped, machined to produce 74 mm diameter cylindrical billets and cut into two halves along the length. Cylindrical billets of 74 mm diameter and 125 mm height were ready for subsequent extrusion processing. Billets were extruded at an initial billet temperature of 420°C, extrusion ram speed of 3 mm/sec and extrusion ratio of 20:1.
  • the extrusions were solution treated at 460°C for 1.5 h, quenched in water at ambient temperature and peak aged using a two-step aging treatment involving 8 h at 100°C in the first step followed by aging at 120°C for 24 h in the second step. This heat treatment produced peak strength in the alloy. These peak aged extrusions were then utilized for evaluation of the tensile properties (see Table 1).
  • Example 2 Preparation of Al-12.1 wt% Zn-1.5 wt% Mg-1.8 wt% Cu-0.16 wt% Zr
  • the charge was superheated to 760°C and the whole material was held at this temperature for 10 minutes.
  • the temperature was then reduced to 740°C and 0.03 kg of nucleant pellets were added for grain refinement purpose.
  • 0.04 kg of degasser pellets were added for degassing purpose.
  • the molten alloy, at a temperature of 720°C, was then poured under argon atmosphere into a preheated (to the temperature of 150°C) metallic mould of suitable size.
  • a cylindrical as-cast billet of 95 mm diameter and 250 mm height was obtained.
  • the billet was subjected to two-step homogenization treatment comprising of 24 h at 445°C followed by 24 h at 455°C followed by cooling in air.
  • the billet was scalped, machined to produce 74 mm diameter cylindrical billets and cut into two halves along the length. Cylindrical billets of 74 mm diameter and 125 mm height were ready for subsequent extrusion processing. Billets were extruded at an initial billet temperature of 420°C, extrusion ram speed of 3 mm/sec and extrusion ratio of 20:1.
  • the extrusions were solution treated at 460°C for 1.5 h, quenched in water at ambient temperature and peak aged using a two-step aging treatment involving 8 h at 100°C in the first step followed by aging at 120°C for 24 h in the second step. This heat treatment produced peak strength in the alloy. These peak aged extrusions were then utilized for evaluation of the tensile properties (see Table 2).
  • a mixture of 41.154 kg of primary aluminium (purity 99.85 wt% Al and the balance being a maximum of 0.09 wt% Fe and 0.06 wt% Si impurities) and 2.72 kg of Al-33 wt% Cu master alloy was charged into the induction furnace.
  • the above charge mixture was melted at 725°C.
  • 4.225 kg of pure Zn in the ingot form was added.
  • the temperature of the molten charge was raised to 740°C and 1.562 kg of Al-50 wt% Mg master alloy and 0.339 kg of Mg-28 wt% Zr master alloy were added in the above sequence.
  • the charge was superheated to 760°C and the whole material was held at this temperature for 10 minutes.
  • the temperature was then reduced to 740°C and 0.10 kg of nucleant pellets were added for grain refinement purpose.
  • 0.25 kg of degasser pellets were added for degassing purpose.
  • the molten alloy at the temperature of 720°C was then poured under argon atmosphere into a preheated (to the temperature of 150°C) metallic mould of suitable size.
  • a rectangular as-cast billet of 340 mm (length) ⁇ 300 mm (width) ⁇ 100 mm (thickness) was then obtained.
  • the billet was subjected to the homogenization annealing in two steps annealing at 450°C for 25 h in the first step and annealing at 460°C for 15 h in the second step followed by cooling in air.
  • the homogenized billet was scalped in order to remove the oxidized layers on the surfaces of the billet.
  • the billet was subjected to hot rolling. Hot rolling was carried out at an initial billet temperature of 425°C and at a linear speed of 20 m per minute.
  • the same hot rolling cycle was continued till such time the targeted plate thickness of 22 mm was achieved and subsequent cross rolling was carried out to obtain the sheet thickness of 5 mm.
  • the hot rolled sheets were then subjected to cold rolling.
  • the sheets were subjected to the same cycle till such time the thickness of 0.28 mm i.e. the targeted thickness of below 0.30 mm was achieved.
  • the sheets were then subjected to solution treatment at 460°C for 1 h followed by water quenching at room temperature.
  • the sheets were then subjected to artificial aging at 100°C for 8 h followed by artificial aging at 120°C for 24 h. This heat treatment produced peak strength in the alloy. These peak aged materials were then utilized for evaluation of the tensile properties (see Table 3).
  • a mixture of 40.536 kg of primary aluminium (purity 99.85 wt% Al and the balance being a maximum of 0.09 wt% Fe and 0.06 wt% Si impurities) and 3.03 kg of AI-33 wt% Cu master alloy was charged into the induction furnace.
  • the above charge mixture was melted at around 725°C.
  • 4.825 kg of pure Zn in the ingot form was added.
  • the temperature of the molten charge was raised to 740°C and 1.288 kg of Al-50 wt% Mg master alloy and 0.321 kg of Mg-28 wt% Zr master alloy were added in the above sequence.
  • the charge was superheated to 760°C and the whole material was held at this temperature for 10 minutes.
  • the temperature was then reduced to 740°C and 0.10 kg of nucleant pellets was added for grain refinement purpose.
  • 0.25 kg of degasser pellets was added for degassing purpose.
  • the molten alloy at the temperature of 720°C was then poured under argon atmosphere into a preheated (to the temperature of 150°C) metallic mould of suitable size.
  • a rectangular as-cast billet of 340 mm (length) ⁇ 300 mm (width) ⁇ 100 mm (thickness) was then obtained.
  • the billet was subjected to the homogenization annealing in two steps annealing at 450°C for 25 h in the first step and annealing at 460°C for 15 h in the second step followed by cooling in air.
  • the homogenized billet was scalped in order to remove the oxidized layers on the surfaces of the billet.
  • the billet was subjected to hot rolling. Hot rolling was carried out at an initial billet temperature of 425°C and at a linear speed of 20 m per minute.
  • the same hot rolling cycle was continued till such time the targeted plate thickness of 22 mm was achieved and subsequent cross rolling was carried out to obtain the sheet thickness of 5 mm.
  • the hot rolled sheets were then subjected to cold rolling.
  • the sheets were subjected to the same cycle till such time the thickness of 0.28 mm i.e. the targeted thickness of below 0.30 mm was achieved.
  • the sheets were then subjected to solution treatment at 460°C for 1 h followed by water quenching at room temperature.
  • the sheets were then subjected to artificial aging at 100°C for 8 h followed by artificial aging at 120°C for 24 h. This heat treatment produced peak strength in the alloy. These peak aged materials were then utilized for evaluation of the tensile properties (See Table 4).
  • the tensile properties of the alloys of examples 1-4 of present disclosure were examined using tensile tests carried out at ambient temperature on tensile specimens (25 mm gauge length).
  • the alloys of example 1 and 2 were tested on round bar tensile specimens (25 mm gauge length) while alloy of example 3 and 4 were tested on flat tensile specimens.
  • Tables 1 to 4 represent the tensile test results for examples 1 to 4, respectively.
  • FIG. 1 shows the partially recrystallized grain structure in the peak aged alloy extrusions of present disclosure.
  • the obtained data of 0.2% P.S. values is consistent with the retention of subgrain structure ( Figure 3 ) in the predominantly unrecrystallized grain structure in the peak aged alloy extrusions and essentially unrecrystallized grain structure in the peak aged sheets of thickness 0.28 mm ( Figure 2 ) of present disclosure. It also characterizes the presence of a uniform and fine distribution of strengthening ⁇ precipitates in the peak aged alloy extrusions ( Figure 4 ) and alloy thin sheets ( Figure 5 ).

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Claims (4)

  1. Aluminium-Zink-Magnesium-Kupfer-Zirconium-Legierungsextrusion (Al-Zn-Mg-Cu-Zr) mit der folgenden Zusammensetzung in Gewichts-%:
    Zn 11,5 bis 12,5;
    Mg 1,3 bis 2,0;
    Cu 1,5 bis 2,2; und
    Zr 0,16 bis 0,18 und wobei der Rest Aluminium ist,
    wobei die Legierungsextrusion eine hohe Festigkeit aufweist und im Wesentlichen eine nicht rekristallisierte Kornstruktur bewahrt und während der Extrusionsverarbeitung Lösungswirkung verleiht.
  2. Verfahren zur Herstellung von Aluminium-Zink-Magnesium-Kupfer-Zirconium-Legierungsextrusion (Al-Zn-Mg-Cu-Zr) mit der Zusammensetzung nach Anspruch 1, wobei das Verfahren umfasst:
    a. Schmelzen einer Beschickungsmischung aus Primäraluminium und Al-33-Gew.-%-Cu-Vorlegierung;
    b. Hinzugeben von reinem Elementar-Zn, gefolgt vom Erhöhen der Temperatur der geschmolzenen Beschickung;
    c. Hinzugeben von Al-50-Gew.-%-Mg-Vorlegierung und Mg-28-Gew.-%-Zr-Vorlegierung zu der geschmolzenen Beschickung, gefolgt von Überhitzung;
    d. Kornfeinen durch Hinzugeben von Nukleationspellets bei einer verringerten Temperatur;
    e. Entgasen durch Hinzugeben von Entgasungspellets;
    f. Gießen der geschmolzenen Schmelze unter Argonatmosphäre in eine vorgeheizte metallische Form;
    g. Erstarren zum Erhalten eines wie gegossenen Knüppels aus Legierung;
    h. Unterziehen des Knüppels einer Homogenisierungsbehandlung, die von 25 bis 35 Std. bei 440 bis 450°C, gefolgt von 20 bis 30 Std. bei 450 bis 460°C, gefolgt von Kühlung in Luft umfasst;
    i. Grobsieben und Bearbeiten;
    j. Extrudieren des bearbeiteten Knüppels, wobei der während der Extrusionsverarbeitung Lösungswirkung verliehen wird,
    k. Lösungsbehandlung, Abschrecken in Wasser, und
    l. Auslagerungsbehandlung in zwei Stufen während 6 bis 8 Std. bei 90 bis 100°C im ersten Schritt, gefolgt von Auslagern bei 120 bis 125°C während 20 bis 25 Std. im zweiten Schritt, um eine Legierung mit hoher Festigkeit zu erhalten, die eine im Wesentlichen nicht rekristallisierte Kornstruktur bewahrt.
  3. Verfahren nach Anspruch 2, wobei die Extrusionsverarbeitung bei Ausgangsknüppeltemperaturen im Bereich von 400 bis 430°C, mit einem Formänderungsverhältnis im Bereich von 15:1 bis 25:1 und einer Kolbengeschwindigkeit von 2 bis 5 mm/s durchgeführt wird.
  4. Verfahren nach Anspruch 2, wobei die Lösungsbehandlung im Temperaturbereich von 450 bis 460°C während 1 bis 2 Std., gefolgt von Abschrecken in Wasser bei Raumtemperatur durchgeführt wird.
EP08738391.5A 2007-03-30 2008-03-27 Legierungszusammensetzung und herstellungsverfahren dafür Active EP2274454B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IN732DE2007 2007-03-30
IN731DE2007 2007-03-30
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EP2644726A4 (de) * 2010-11-22 2016-06-29 Korea Automotive Tech Inst Aluminium-magnesium-legierung und herstellungsverfahren dafür
CN102703782A (zh) * 2012-04-20 2012-10-03 北京工业大学 一种超高强高淬透性Al-Zn-Mg-Cu合金
CN102935494A (zh) * 2012-11-13 2013-02-20 东北轻合金有限责任公司 一种小规格铝合金圆铸锭的制造方法
CN105200288A (zh) * 2015-11-02 2015-12-30 东北轻合金有限责任公司 一种超高强铝合金棒材及其制造方法
CN105671408A (zh) * 2016-04-20 2016-06-15 苏州市相城区明达复合材料厂 一种型材加工用高强度铝合金
CN106367644B (zh) * 2016-09-23 2018-03-13 北京工业大学 一种超高强、高硬度TiB2颗粒增强Al‑Zn‑Mg‑Cu复合材料及其制备方法
CN107119215B (zh) * 2017-06-27 2019-01-04 中南大学 一种超强铝合金及其制备方法
CN107460382B (zh) * 2017-08-18 2019-04-30 江苏大学 各向同性超强耐蚀铝合金轧制板材及制备方法
CN108707793A (zh) * 2018-06-01 2018-10-26 中国航发北京航空材料研究院 一种改善750MPa级超高强铝合金腐蚀性能的方法
CN109666827B (zh) * 2019-02-22 2021-02-12 洛阳华陵镁业有限公司 一种超强超韧7055Sc铝合金锻件
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CN101835915B (zh) 2012-05-23

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