Preparation of copper powder from copper scale

Effects of powder and press variableson mechanicalproperties of extruded inert gas atomizedAl&vi%Cr-W&alloysam described. HEAT TRANSFER BY CONDUCTION PREPARATION OF COPPER Reducedparticlesize incmasedVlcker’shard AND CONVECTION BETWEEN POWDER FROM COPPER SCALE ness and tensileslrengthby up to 24% values DROPLET AND TWO-PHASE FLUID J.Lezanski, J.Olszewska. (Academia F.Folio, ALacour. (Universityof Clermont- establishinga Petch relationship.Increasein extrusion temperature reduced mechaical Gorniczo-Hutnicza, Krakow, Poland.) Ferrand, Alubiere, France.) ht. J. Rapid properlies. Powderextrudedat350°Cexhibii Metal. Proszkow, Vol29, No 2, 1996, 10-13. Solidif?catim, Vol9, No 2,1996,7589. age hardening whichis atributedto retentionof (In Polish.) A method for modelling heat transfer Characterization and preparation of and cooling rate of atomized particles in a Ziin solidsolution Cu scale for conversion into elemental Cu cryogenic atmosphere is described. The METHODSOFANALYSISOFNAN~ powder are outlined. It is reported that model is based on a geometric analogy and CRYSTALLJNEMATERIAIS involves Reynolds and Nusselt numbers clean Cu powder had been produced. and whether the coolant is a fluid or a gas O.Drbohlav. (PRAMET a.s., Sumperk, Pokroky Praskove fluid mist. Experiments were carried out Czechoslovakia.) Pressing using heated Pt wires. Relationships gov- Mei?&@, No 1,1996,4149.(InCzech.) Experiencesin characterizationof nano erning heat transferbetween spherical parDEFORMABILITY OF POWDER crystalline materialsby X-ray diliaction and ticles and a coolant mist, and cooling rates MATERIALS FOR MAKING magnetic measurements am summarizedand in Newtonian conduction are established. COMPOSITES BY ROLLING

Powder Production

Fundamentals

I.N.Zigalo et al. Poroshkovaya Metal. No 314, 1996, 19-24. (In Russian.) Deformation capacity of ferrous alloys, with Zr, Ti or rare earths and graphite in powder rolled and ingot materials was investigated. The possibility of hot rolling and drawing composite materials with powder inserts is demonstrated.

CALCULATION OF MODEL OF STRESS-STRAIN STATE IN PRESSED LAYERS

ROTARY ROCKING CONSOLIDATION OF METAL POWDER COMPACTS M.Kobayashi. (Chiba Polytechnical University, Japan.) Metals Technol., Japan, Vol 65, No 6, 1995, 248249. (In Japanese). Compaction in dies between punches rotating in the same direction with the lower punch moving upwards to create shear flow is reported to result in removal of pores from the compact giving high green density. Effects of powder morphology are tabulated. Compaction of a range of materialsis discussed. SIMULATION OF INDUSTRL4L POWDER COMPACTION BY A PLASTICITY MODEL S.Oller et al. (Polytechnic University of Catalonia, Spain.) Int. J. Solids Structures, Vol 33, No 20122. 1996. 31613178. A model, based on large strain plasticity, of powder compaction is presented. Elastic response in terms of a model based on elastic free energy is stated and plastic response is related to a two-parameter yield surface. Application to a process is demonstrated.

40

MPR September

1997

V.G.Ka,juk.Poroshkovaya Metal., No 314, 1996,3@36. (In Russian.) The theory of linear elasticty was applied to the problem of displacementand stresses in compacted layers. It is shown that the relationships for components of displacement and stress depends on gee metrical and mechanical parameters. Predicted and measured results are compared. YIELD FUNCTION PARAMETERS FOR METAL POWDER COMPACTION C.Pavanachand, RKrlshnakumar. (Indian Inst. of Technology, Madras, India.) Acta Mater. Vol45, No 4,1997,14251444. A new method for evaluation of the mechanics of powder deformation is described. Two-dimensional close-packed arrays at two densities are considered and studied under plane-strainconditions using fin&e element analysis in the density range 78 to 98%. Yield function parameters are calculated and shown to agree well with experimental data for Cu, Al and Fe. Yield function is affected by pore shape, loading path, work hardeningand interparticlefriction. A single density related function did not describe yield function parameters throughthe densityrange. EFFECT OF PARTICLE SIZE AND EXTRUSION PARAMETERS ON PROPERTIES OF ALUMINIUM ALLOY H.Jones et al. (University of Sheffield, Sheffield, UK) hat. J. Rapid SoZidifxatim, Vol9, No 1, 1996,4561.

Aluminium AGE HARDENINGBEHAVIOUROF ALUMINIUM-COPPERPREIWRMS T.S.Raoet al (RegionalEngineeringCollege, l-kuchlpalli,India)PM Sci. Tech&, Vo16,No 4,1996,1924. An account of age hardeningin sin&red and extrudedAl-(1.5,2.5or 4.O)wtokcu alloysis presented. Solution treatmentat 599°C was followed by aging at 170, 180 and 190°C. Propertieswere determinedat peak hardness. lncreased Cu improved aging response and incmasedtensilestnmgth COMPACTINGAND SBUTERJNG OF ALUMINIUM-LEADKBYDER MIXlURES D.Nath et al. (Benaras Hindu University, Benams,India)PM Scimm TM, Vo16,No 4,1996,2531. processing of Al-15Wb was inv~ forpm&ngat109to469MPaandsinteringat 529,569 or 669°Cin N. lncmasedcompaction pressureis reportedto increaseejectionpres sure, springback and green properties.At a flxed sir&ring temperatureincreased compaction pressure increased density and mechanicalpropertiesand reduced porosity. are reported ChaIlgesinsinmmlgmmpemmm tohavellttleeffectonproperties DIFFUSIONOF COPPERIN MECBANICALLYALWYEDNANO CRYSTALLINEALUMINIUMALLOY T.Yamaneet al @lm&ima lnst of Technology, Him&ma, Japan)Mater. Tmns. JIM, Vo137, No 2,1996,130-137. It is reported that supersaturated nanocrystalline Al-7.8at%Ti-0.3 powder