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