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Advances in PowderConsolidation at Ceracon
FIG. 2 Ceracon demonstrations ofbulk shape superconductorfabrication capability underDARPA sponsorship
facture of large 50 pound parts (per.cussivo hammer bits for Numa Tool)and complex shaped triconal drill bits(MPIFPart of the Year Distinction in1989)for Reed Tool Company (Fig. 3).Here the process offered overall fabrication cost savings of 50% overconventional processes while allowing for significant performanceimprovement. An 84 kilowatt furnacecapable of handling 300 Iblhr of grainuptoa temperatureof2150Fhas beendesigned and installed. A large coldisostatic press having a work processzone of 8in. in diameter and 32in. inheight is extensively used in the fabrication of the preforms. Extensivesoft tooling capabilities for C1.P andCADcapabilities forcomplex preformdesigning have also been developed.A 2500 ton press has been acquired toallow for the manufacture of largeparts. A physical plant expansionfromcurrently 6000 ft2to 16,000 ftz isin process and is scheduled for completion by April 1990.Development work is underway forMack Truck. Caterpillar Tractor Co,Ingersoll Rand, Timken. and Norton-Christiansen. Areas of involvement range from automotive. truck,earth moving, roller bearing, to drilling parts. The Ceracon Process,because of its high-speed fabricationcapability and low-cost manufacturing advantages. is expected to beincreasingly used in the fabrication ofceramic cutling tools. armour materials, novel refractories. intermetalllcmatrix composites. bulk supcrconductors, and mechanically-alloyedmaterials such as nickel and copperbase high-conductivity high-strengthmaterials.
FIG. 3 Roller cone drill bit coated \I'ith tungsten carbide used in oil welldrilling produced byCeracon Inc. Thecomponent won the 'Fully DenseA\I-ard oj Distinction' in the MPIF 1989 PM Patt-oj-the-YearCompetition
nally presented a problem in the consolidation of Al based materials.However, the differential axial andlateral pressures generated on the partduring consolidation allow for shearing action between particles to resultin the removal of the oxide layer.Consolidation of 2124 aluminumalloy using the process resulted in ahigher level of ductility relative tothat obtained by sintering or hot forging processing and is comparable towrought material. When applied topowder processed preforms of AISiC(p) good dispersion of SiC particulates in the aluminum matrix isobtained. while achieving full density.Excellent grain alignment is obtainedfor Nd·Fe-B permanent magnet processing. resulting in a significantenhancement in magnetic properties.The company was also selected as oneof the 33 prime contractors by theDARPA to apply the unique processing advantages ofthe Ceracon Processto the consolidation of YBazCuJ0J.x(YBCO) superconductors. This allowed for the fabrication of bulk superconductors of cylindrical (hollow andsolid). spherical and disk shapes. aswell as composites of silver andYBCO superconductors (Fig. 2).These bulk superconductor partsshowed a uniform density (>95% oftheoretical) and microstructurethroughout the cross-section, 90Ksuperconducting transition temperature and preserved the fine grain sizeand high phase purity of the startingpowders and crack-free micro/macrostructure. These types of results areyet to be demonstrated by other competing process technologies for fabricating monolithic superconductors.A further project concerns the manu-
APPLICATIONS
preheated and lowered into the hotPTM.Uniaxial pressures ofup to 1250MPa are applied to the PTM for holdtimes of up to a maximum of 60seconds. The applied pressure istransmitted via PTM and instantaneous consolidation occurs. The die isthen depressurised, the part removedfrom the grain. and the grain is recycled. High speed fabrication of a part ispossible while the desired characteristics of the particulate material. inthe consolidated product. are preserved.
Recent R&D programmes have demonstrated that the Ceracon Process isuniquely suited for the consolidationof rapidly solidified aluminumalloys. intermetallics, AI-SiC. NdFe-B magnets. high AlzOJ contentFe-AlzOJ composites. and bigh-T,superconductors.The oxide layer covering the aluminum powder particle has traditio-
metallurgy equipment. It is essentially a quasi-isostatic, hot consolidation technique which utilises apreheated proprietary granularmaterial as a pressure transmittingmedium (PTM) instead of a gas asused in HIP. A cold isopressed preform of the part to be consolidated is
led gr In tills tn die1.
The increasing demand for low-costmanufacturing processes suited forthe fabrication of high performancematerials by aerospace. energy. andautomotive industries. has led to abroad range of applications for theCeracon Process developed byCeracon Inc of Sacramento. Califor-
FIG. 1 A schematic of The Ceracon Process
The process which is illustrated inFig. 1 utilises conventional powder
THEPROCESS
nia. The process which is protectedby 21 US patents, has. because of itsunique capability to consolidaterapidly at relatively lower temperatures. been demonstrated to be ideallysuited for the consolidation of rapidlysolidified powders. high temperatureceramic superconductors. intermetallic compounds. and metal-matrixcomposites. Ceracon is currentlyworking with several other organisations (Caterpillar, GE, Mack Truck.Comalco, Timken, Ingersoll Rand) toapply its process technology for fabricating advanced parts. The company is also engaged in research programmes for the Defense AdvancedResearch Projects Agency (DARPA)on bulk superconductors and National Aeronautics and Space Administration (NASA) for niobium aluminides,
246 MPR April 1990