Classifications

• • 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
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/0408—Light metal alloys
  • C22C1/0416—Aluminium-based alloys
• • 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
  • C22F1/053—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 of alloys with zinc as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/18—After-treatment

Definitions

• the invention relates to a process for obtaining an Al alloy of the 7000 series (Al-Zn-Mg-Cu) with high mechanical strength and good ductility by "spray-deposition" (spray deposition). More specifically, the method aims to obtain Al alloys which have in the treated state (T6) a breaking load ⁇ 800 MPa with an elongation, at least in the long direction, greater than or equal to 5%.
• the invention also relates to obtaining composite materials with very high strength, high rigidity and good ductility having as matrix the 7000 alloys described above with a particulate reinforcement of ceramics and obtained directly by "spray-deposition".
• spray-deposition is meant a process in which the metal is melted, atomized by a jet of gas at high pressure in the form of fine liquid droplets which are then directed and agglomerated on a substrate so as to form a massive and coherent deposit, containing low closed porosity.
• This deposit can be in the form of billets, tubes or plates whose geometry is controlled.
• a technique of this type is known as “Spray Deposition” by the Anglo-Saxons and is also called “OSPREY process”.
• the volume fraction of precipitates at the base of the structural hardening of the alloy (essentially of the type ⁇ -Mg Zn2 or ⁇ ′ - (Mg, Zn, Al, Cu)) becomes insufficient and it is no longer possible to obtain the high levels of mechanical characteristics (such as breaking load ⁇ 800 MPa) which are the objective of the present invention.
• the volume fraction of the second phase is too high and leads to a brittle material, with very low elongations at break, which prohibits its industrial use.
• the copper and magnesium contents must be in proportions close to the stoichiometry of the hardening precipitates.
• Mg ⁇ 2% or Cu ⁇ 0.5% the nature and the volume fraction of the precipitates formed are insufficient to achieve the targeted mechanical characteristics.
• Mg is ⁇ 4% or Cu ⁇ 2.0%, these elements are present in excess in the alloy and weaken it considerably.
• the preferred composition is: Zn from 8.7 to 13.7% 2.2 to 3.8% mg Cu from 0.6 to 1.6% at least one of the following 3 elements: Zr from 0.05 to 0.5% Mn from 0.05 to 0.8% Cr from 0.05 to 0.5% with Zr + Mn + Cr ⁇ 1.2% Fe up to 0.3% If up to 0.2% other (impurities) ⁇ 0.05% each ⁇ 0.15% total remains Al.
• the content of main elements preferably obeys the following relationship, 5.5 ⁇ Mg + Cu + Zn 6 ⁇ 6.5
• the hot transformation of the solid alloy obtained by spray-deposition generally takes place between 300 and 450 ° C, preferably by spinning, forging or rolling, in one or more successive operations; these operations may possibly be combined, for example spinning + rolling or spinning + forging / stamping.
• the hot transformation operations can be supplemented by cold operations such as rolling, drawing, etc.
• the solution is carried out between 440 and 520 ° C, between 2 and 8 hours depending on the size of the products; quenching is followed by tempering between 2 and 25 h between 90 and 150 ° C in one or more stages, the longest times generally being associated with the lowest temperatures (and vice-versa).
• the product obtained by a spray-deposition process can optionally be homogenized before hot transformation between 450 and 520 ° C for 2 to 50 hours in one or more stages.
• the invention also consists, using the alloys and the method described above, in obtaining composite materials with very high resistance (Rm ⁇ 800 MPa), high Young modulus (E ⁇ 80 GPa), with acceptable ductility by users (A ⁇ 3%), as well as good resistance to wear and friction.
• These materials are characterized by an alloy matrix of the 7xxx series of composition indicated above and a dispersion of ceramic particles of SiC, Al2O3 or B4C type (these examples not being limiting) and are obtained directly by the spray-deposition technique.
• the blanks are then hot-spun at 400 ° C in a press whose container has a diameter of 143 mm in the form of flats of section 50 x 22 mm, ie a spinning ratio of 14.6.
• the flats thus obtained are then dissolved at the temperature indicated in Table 1 for 2 h, quenched in cold water and then returned for 24 h at 120 ° C.
• the mechanical tensile characteristics in the long direction, average of 3 tests, are reported in Table 2 (Ro, 2: elastic limit at 0.2% residual deformation, Rm: breaking load; A%: elongation at break).
• alloys No. 1 to 4 according to the invention exhibit a very high level of mechanical properties, in particular with a tensile strength of ⁇ 800 MPa and a correct level of ductility, with elongations at rupture ⁇ 5% .
• Alloy 5 outside the analytical limits of the invention (Zn content too low) has much weaker mechanical characteristics than the alloys of the invention.
• Alloy 6 also outside the limits of the invention due to its too high Zn content, has a very low ductility (A%) and a plastic difference (Rm- R 0.2).
• Alloy 8 is an alloy whose composition falls within the analytical field of the alloys of the invention but which has been developed according to a powder metallurgy process described below: the alloy is melted and then atomized with nitrogen in the form powders; these are collected and sieved to 100 ⁇ m. Powders smaller than 100 ⁇ m are put in 140 mm diameter aluminum containers fitted with an orifice tube and are then degassed hot under secondary vacuum (by pumping through the tube) at a temperature of 460 ° C for 100 h. The powder containers thus degassed are sealed and then hot pressed in a blind die spinning press in a 143 mm diameter container at 450 ° C so as to reach the theoretical density of the material.
• the billets thus obtained are then machined in order to remove the material from the container and then spun under the same conditions as the billets of the previous examples.
• the product obtained is heat treated according to a similar procedure (see solution temperature in Table 1) and is characterized under the same conditions.
• the results reported in Table 1 show that the product obtained has very low ductility and plastic difference despite a relatively high level of resistance.
• An alloy of composition Al Al: 10% Zn; 3.0% Mg; 1.0% Cu; 0.1% Zr; 0.15% Cr; 0.15% Mn, rest Al was melted at 750 ° C and produced by spray-deposition in the form of 150 mm diameter billets with simultaneous coinjection of SiC particles of average size 10 ⁇ m, with a volume fraction of 15%.
• the spray-deposit conditions were as follows: - metal flow: 5.8 kg / min. - gas flow: 15 Nm3 / min. - atomizer-deposit distance: 620 mm, kept approximately constant during the test - stainless steel collector with rotating movement - oscillation of the atomizer relative to the axis of rotation of the collector
• the billets thus obtained are then peeled to ⁇ 140 mm, homogenized for 8 hours at 470 ° C, hot spun at 400 ° C in the form of flats with a section of 50 x 22 mm (spinning ratio 14.6).
• the spray-deposition process according to the invention in addition to the best compromise of mechanical characteristics obtained, has the following advantages over conventional powder metallurgy: - long and costly degassing and compaction operations are avoided - the method is safer, since there is no handling of reactive powders.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Plasma & Fusion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Crystallography & Structural Chemistry (AREA)
• Powder Metallurgy (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)
• Coating By Spraying Or Casting (AREA)
• Laminated Bodies (AREA)
• Conductive Materials (AREA)
• Forging (AREA)
• Wrappers (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

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Cited By (6)

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Citations (4)

• 1988
  • 1988-12-19 FR FR8817044A patent/FR2640644B1/fr not_active Expired - Fee Related
• 1989
  • 1989-12-14 HU HU896605A patent/HUT53681A/hu unknown
  • 1989-12-14 US US07/450,525 patent/US4995920A/en not_active Expired - Fee Related
  • 1989-12-15 DD DD89335750A patent/DD290024A5/de not_active IP Right Cessation
  • 1989-12-15 IL IL92727A patent/IL92727A0/xx unknown
  • 1989-12-18 BR BR898906543A patent/BR8906543A/pt unknown
  • 1989-12-18 NO NO89895100A patent/NO895100L/no unknown
  • 1989-12-18 AT AT89420497T patent/ATE90976T1/de not_active IP Right Cessation
  • 1989-12-18 AU AU46816/89A patent/AU615366B2/en not_active Ceased
  • 1989-12-18 EP EP89420497A patent/EP0375571B1/de not_active Expired - Lifetime
  • 1989-12-18 DE DE89420497T patent/DE68907331T2/de not_active Expired - Lifetime
  • 1989-12-18 CA CA002005747A patent/CA2005747C/fr not_active Expired - Fee Related
  • 1989-12-19 JP JP1329365A patent/JPH02258935A/ja active Pending
• 1990
  • 1990-01-02 TR TR90/0007A patent/TR24392A/xx unknown

Patent Citations (4)

Non-Patent Citations (3)

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