Classifications

• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/12—Both compacting and sintering
  • B22F3/1208—Containers or coating used therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/002—Making metallic powder or suspensions thereof amorphous or microcrystalline
  • B22F9/008—Rapid solidification processing
• • 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
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C45/00—Amorphous alloys
  • C22C45/08—Amorphous alloys with aluminium as the major constituent

Definitions

• the invention is based on an aluminum alloy, suitable for rapid cooling from a melt oversaturated with alloy components, according to the preamble of claim 1.
• the aluminum alloys cited in the above publications are predominantly of a type with relatively high iron contents. In the primary solidification state, which is present as powder, flakes, strips after rapid cooling from a melt, they have very high strengths and cause difficulties in the subsequent compression to form compacts. Either higher pressures or higher temperatures are required, which is complex on the one hand and on the other hand involves the risk of not achieving the optimal microstructure for the end product (cf. J. Duszcuzyk and P. Jongenburger, TMS-AIME Meeting, New York, 24 - Born 28, 1985; RJ Wanhill, PM Aerospace Materials Conference, Berne, Nov. 1984; GJ Hildeman, DJ Lege and AK Vasudevan, High Strength PM Aluminum Alloys, eds. Koczak and Hildeman, 1982, p. 249).
• Aluminum alloys containing chromium and manganese which enable the formation of supersaturated solid solutions, are softer and more ductile and, consequently, easier to compress and process than powder (see P. Furrer and H. Warlimont, Mat. Sci. And Eng. 28 , 1977, 127; R. Yearim and D. Schcktman, Met. Trans A., 13A , 1891-1898, 1982; EP-A-0 105 595; IR Hughes, GJ Marshall and WS Miller, 5th Conference on Rapidly Quenched Metals, Würzburg, Sept. 1984).
• the invention is based on the object of specifying aluminum alloys which are well suited for the production of ultra-fine-grained powders from melts which are oversaturated with alloy components and have improved mechanical and structural properties.
• compositions are to be sought which form ductile, easily processable structures and phases under the proposed cooling conditions and which can be further increased in their strength properties and toughness by suitable heat treatments.
• the guiding principle of the invention is the properties of the binary Al / Cr alloys (supersaturated solid solution, formation of Al13Cr2 dispersoids by alloying with vanadium and possibly of small Improve amounts of other additives. Due to the possibility of the formation of the intermetallic compound Al10V, which has a low density, that is to say a large specific volume, the volume fraction of strength-increasing, finely divided dispersoids in the end product is drastically increased. In addition, the simultaneous presence of chromium and vanadium has a mutually supportive effect on the thermal stability, the heat resistance and the toughness with good ductility of the alloy.
• an alloy was melted from the pure components Al, Cr and V in the induction furnace under vacuum in a silicon carbide crucible and poured into a water-cooled copper mold.
• the solidified ingot weighed approximately 1.5 kg. It was mechanically cut into smaller pieces which were placed in a silicon carbide crucible of the atomizer.
• the container of this device was then evacuated to a residual pressure of approx. 1.5 Pa, flooded with nitrogen, evacuated again, flooded again with nitrogen and evacuated again. Under these conditions, the batch was melted using an inductive heater and brought to a temperature of 1150 ° C. Now the container was filled with nitrogen and the inductive heating was switched off.
• the alloy powder was then filled into a thin-walled cylindrical aluminum can 70 mm in diameter and 250 mm high.
• the can was evacuated, heated to 450 ° C and left under vacuum at this temperature for 2 h.
• the residual gas pressure was approximately 0.15 Pa.
• the can was then sealed by compressing the suction nozzle and placed in a press.
• the encapsulated alloy powder was compressed at 450 ° C to 96% of the theoretical density of the compact material.
• the compacted and cooled blank was removed from its aluminum shell by mechanical processing and inserted into an extrusion press as a press bolt puts. A rod with a diameter of 15 mm was pressed at a temperature of 460 ° C. (reduction ratio 1:22).
• the strength and ductility values were monitored during the implementation of the process and on the end product.
• a Vickers hardness of 120 (HV) could be measured on the freshly solidified material without any heat treatment, which indicated good ductility.
• the Vickers hardness at room temperature after a heat treatment at a temperature of 400 ° C. and a duration of 1 h was determined at 190 (HV) on a finished extruded test specimen. This increase shows not only the striking effect of the hardening dispersoids but also their excellent thermal stability.
• An alloy was melted from suitable Al / Cr and Al / V master alloys in an alumina crucible under an inert gas atmosphere in an induction furnace and an ingot of approx. 1 kg was cast. 400 g of this ingot were inductively melted in a device and, as a jet under high pressure, hurled in the first gas phase against the circumference of a cooled copper disk which was at a peripheral speed of 12 m / s (so-called "melt-spinning" process). Due to the high cooling rate an ultra-fine-grained tape with a thickness of approx. 30 ⁇ m was produced. The tape was crushed and ground into fine-grained powder.
• a cylindrical capsule made of ductile aluminum sheet 60 mm in diameter and 60 mm in height was filled with the powder, evacuated and welded. Then the filled capsule was hot pressed at 420 ° C. under a pressure of 200 MPa to the full theoretical density.
• the capsule was removed by mechanical processing and the pressed body was inserted as a press bolt of 40 mm in diameter into an extrusion press with a reduction ratio of 25: 1 and pressed at 400 ° C. into a rod of 8 mm in diameter.
• the test gave the following results:
• the strip which primarily solidified from the supersaturated melt by rapid cooling, had a Vickers hardness of 135 (HV).
• the finished extruded body was subjected to a heat treatment at a temperature of 400 ° C and for 2 hours. It showed a Vickers hardness of 205 (HV), which indicated high strength.
• the alloy was atomized, compacted, pressed and processed into a round rod to give an ultrafine-grained powder of 20 ⁇ m average particle size.
• the strip which solidified directly from the melt, had a Vickers hardness of 140 (HV).
• the finished test specimen had a Vickers hardness (measured at room temperature) of 185 (HV) after a heat treatment at 400 ° C. for 1 h.
• the invention is not restricted to the exemplary embodiments.
• the aluminum alloy can in principle contain 2 to 5.5% by weight of Cr, 2 to 5.5% by weight of V and optionally one or more of the metals Mo, Zr Ti or Fe in a total content of at most 1% by weight , Al exist, the total content of all alloying elements being at most 10% by weight.
• the aluminum alloy should preferably contain at least 1.2% by weight of the Al13Cr2 phase and at least 1.1% by weight of the Al10V phase embedded in a solid solution.
• the structure of the aluminum alloy should also preferably contain at least 1.2% by weight of the Al13Cr2 phase and at least 1.1% by weight of the Al10V phase as a finely divided dispersoid of at most 0.1 ⁇ m particle diameter.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)
• Powder Metallurgy (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Continuous Casting (AREA)

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• 1986
  • 1986-05-14 EP EP86106579A patent/EP0207268B1/fr not_active Expired
  • 1986-05-14 DE DE8686106579T patent/DE3665077D1/de not_active Expired
  • 1986-06-18 US US06/875,732 patent/US4726843A/en not_active Expired - Fee Related
  • 1986-06-23 JP JP61146751A patent/JPS624851A/ja active Pending
  • 1986-06-23 CA CA000512232A patent/CA1282267C/fr not_active Expired - Fee Related
  • 1986-06-25 NO NO862577A patent/NO862577L/no unknown

Patent Citations (2)

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