Classifications

• • 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
  • B22F3/10—Sintering only
  • B22F3/11—Making porous workpieces or articles
  • B22F3/1103—Making porous workpieces or articles with particular physical characteristics
  • B22F3/1112—Making porous workpieces or articles with particular physical characteristics comprising hollow spheres or hollow fibres
• • 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
  • B22F3/10—Sintering only
  • B22F3/11—Making porous workpieces or articles
  • B22F3/1121—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers
  • B22F3/1125—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers involving a foaming process
• • 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
  • B22F3/10—Sintering only
  • B22F3/11—Making porous workpieces or articles
  • B22F3/1121—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers
  • B22F3/1134—Inorganic fillers
• • 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
  • C22C1/08—Alloys with open or closed pores
• • 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
  • C22C1/08—Alloys with open or closed pores
  • C22C1/083—Foaming process in molten metal other than by powder metallurgy

Definitions

• the invention relates to a method for producing structure-controlled metal foams and the foam-shaped metal bodies obtained in this way.
• DE 197 44 300 A deals with the production and use of porous light metal parts or light metal alloy parts, the bodies pressed from a powder mixture (light metal or aluminum alloy and blowing agent) in a heatable closed vessel with inlet and outlet opening to temperatures above the decomposition temperature of the blowing agent and / or melting temperature of the metal or alloy.
• JP 03017236 A describes a process for producing metallic articles with cavities by dissolving gases in a molten metal and then the foaming process by sudden initiates pressure reduction. Cooling the melt stabilizes the foam thus obtained.
• WO 92/21457 teaches the production of Al foam or Al alloy foam by blowing gas under the surface of a molten metal, with abrasives such.
• metallic foams are obtained with the controlled release of propellant gases by first melting the metals at temperatures below the decomposition temperature of the propellant used. Subsequent dispersion of the blowing agent in the molten metal and heating of the matrix above the temperature then required to release blowing gases establishes a metal foam.
• Foam aluminum is obtained after infiltration of molten aluminum into a porous filler by removing it from the solidified metal (Zhuzao Bianjibu (1997) (2) 1-4; ZHUZET, ISSN: 1001-4977).
• DE 195 01 508 A deals with a component for the chassis of a motor vehicle, which consists of die-cast aluminum and has a cavity profile, inside of which there is a core made of aluminum foam.
• the integrated aluminum foam core is opened beforehand produced by powder metallurgy, then fixed to the inner wall of a casting tool and then with the die casting process
• the infiltration technique in which the porous filler has to be laboriously removed from the foam matrix, must also be assessed from this aspect.
• the dissolving or blowing in of propellant gases in metal melts is not suitable for the production of near-net shape workpieces, since a system consisting of the melt with occluded gas bubbles is not sufficiently stable in time to be processed in shaping tools.
• the mechanical properties of metal foams are essentially - apart from the selection of the metal or alloy used - structurally determined.
• the coupled processes taking place in the manufacture of porous metal bodies often do not produce the desired result of a uniform metal foam with dimensions comparable to globular cells, particularly in the method based on the use of chemical blowing agents.
• isotropy of the spatial density which could be desired for the later function of the metal foam in numerous structural components, is not achieved.
• irregularities are observed in the form of thickened zones in the metal body (for example pronounced foot and / or edge zone formation and / or also connected cavities which result from the combination of individual gas bubbles resulting from cell membrane destruction). The occurrence of such irregularities can also be an indicator of a relatively inefficient use of propellants.
• the object of the present invention is to find a technically usable method for targeted structure control in the metal foams produced with chemical blowing agents. Linked to this, it is important to improve the use of blowing agents (for example a metal hydride).
• a first embodiment for achieving the aforementioned object therefore consists in a process for producing metal foams, which is characterized in that metals from groups IB to VIIIB of the periodic table of the elements are added before and / or during foam formation.
• metals from groups IB-VIIIB of the Periodic Table of the Elements in particular as an addition to hydride-loaded systems, have a morphology-controlling effect and the Increase blowing agent efficiency significantly.
• the added metals of groups IB to VIIIB of the periodic table of the elements can be applied both individually and in the form of a mixture of several metals.
• the method according to the invention therefore provides for the matrix consisting of light metal or light metal alloy and hydride propellant to be expanded with small amounts of titanium, copper, iron, vanadium and mixtures thereof.
• the metallic additives are particularly preferred in amounts of from 0.001% by weight to 1% by weight, particularly preferably from 0.01% by weight to 0.1% by weight, based on the metal to be foamed, in particular on the foaming light metal used.
• a particularly preferred blowing agent in the sense of the present invention is magnesium hydride, in particular autocatalytically produced magnesium hydride, the production of which is known from the literature.
• this magnesium hydride is commercially available from the applicant under the name Tego Magnan®.
• the amount of blowing agent can be varied within the usual limits of 0.1% by weight to 5% by weight, preferably from 0.25% by weight to 2% by weight.
• the use of the observed phenomenon ensures the production of very regular foam structures and ensures the reproducibility of morphologically uniform metal foams, which is required under application-technical aspects.
• the application of the method according to the invention can be used for
• Foaming process help to suppress the process of cell membrane destruction. Evaluation criteria for the qualitative assessment of plastic foams as well as metal foams are, in addition to the visually recognizable homogeneity, the expansion achieved and the associated final density of the porous metal body.
• the compacts were placed in a graphite crucible Heating rate of 300 ° C / min. foamed freely.
• the foam bodies were rapidly cooled 30 seconds after the start of the foaming process.
• Example 2 Analogously to Example 1, 500 g of aluminum powder with 1% by weight of Tego Magnan (magnesium hydride), based on the amount of aluminum powder, 0.1% by weight of titanium powder, based on the amount of aluminum powder and 0.01% by weight of vanadium powder , based on the amount of aluminum powder. This mixture was compacted as described above. The degree of compaction of the cylindrical compacts thus obtained was 94 to 96%.
• Tego Magnan magnesium hydride
• Example 2 Analogously to Example 1, 500 g of aluminum powder, 1% by weight of Tego Magnan (magnesium hydride), based on the amount of aluminum powder, 0.1% by weight of titanium powder, based on the amount of aluminum powder and 0.01% by weight of iron powder , based on the amount of aluminum powder, mixed, compacted and the green bodies obtained are foamed. After sawing it was one homogeneous structure with an average cell size of 5 mm visible. The measured density was 0.7 g / cm 3 .
• Example 2 Analogously to Example 1, 500 g of aluminum powder, 1% by weight of Tego Magnan® ( magnesium hydride), based on the amount of aluminum powder and 0.1% by weight of titanium powder, based on the amount of aluminum powder, were mixed and compacted. The degree of compaction was between 95 and 97% of the theoretically achievable density. The green bodies obtained in this way were foamed and after sawing up a homogeneous structure with an average cell size of 3.5 to 4 mm was recognizable. The measured density was 0.3 g / cm 3 .
• Example 2 Analogously to Example 1, 500 g of aluminum powder, 0.1% by weight of titanium hydride, based on the amount of aluminum powder and 0.1% by weight of titanium powder, based on the amount of aluminum powder, were mixed, compacted and freely foamed. After sawing, a coarse, very heterogeneous foam structure with an average cell size of 8 mm was visible. Several pore membranes were torn. The density determined was 0.7 g / cm 3 .

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Powder Metallurgy (AREA)
• Catalysts (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7685460

Family Applications (1)

Country Status (9)

Families Citing this family (27)

Family Cites Families (18)

• 2002
  • 2002-04-30 JP JP2002591187A patent/JP4344141B2/ja not_active Expired - Fee Related
  • 2002-04-30 EP EP02740540A patent/EP1397223B1/fr not_active Expired - Lifetime
  • 2002-04-30 CA CA002443826A patent/CA2443826A1/fr not_active Abandoned
  • 2002-04-30 AT AT02740540T patent/ATE357304T1/de not_active IP Right Cessation
  • 2002-04-30 AU AU2002314016A patent/AU2002314016A1/en not_active Abandoned
  • 2002-04-30 ES ES02740540T patent/ES2281521T3/es not_active Expired - Lifetime
  • 2002-04-30 DE DE50209776T patent/DE50209776D1/de not_active Expired - Lifetime
  • 2002-04-30 WO PCT/EP2002/004742 patent/WO2002094483A2/fr active IP Right Grant
  • 2002-05-16 US US10/147,152 patent/US6942716B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events