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Corrosion of sintered 316L stainless steel with diborides added
tolerances and materials, were discussed. It was reported that two components had been made by the ISOPREC process for prealloyed powder. This involved HIP of partial or total net shape parts. The parts were shown to meet specification requirements. Development steps and evaluations of parts were presented. IMPROVED CHROMIUM-COBALTMOLYBDENUM ALLOY FOR ORTHOPAEDIC APPLICATIONS F.Duflos, M.Pierronnet. (Tecphy, Imphy, France.) Cr-Co-MO alloys for surgical use were discussed with regard to properties. Fabrication, microstructures and properties of 2 PM materials, low C SY21 MED and high C SY21 MED HC, for suhsequent re-forging or machining, were described. BI-METALLIC PM SUPERALLOY DISCS FOR CML AIRCRAFT ENGINES A.Kazberovitch et al. (All-Russia Inst. of Light Alloys (VILS), Moscow, Russia.) Development of aircraft engines with reduced levels of noise, weight and vibration, for civil use, was discussed with regard to design considerations. One option is to use welded parts. It was reported that rotors had been produced from PM Ni base alloy ring spacers bonded to the disc by HIP. Technological aspects of joining PM spacers to the disc were discussed. DISCS OF MEDIUM ALLOYED PM NICKEL BASE ALLOY G.Genrikh et al. (All-Russia Inst. of Light Alloys (VILS), Moscow, Russia.) It was reported that gas turbine discs had been made from spherical superalloy powders by HIP. These were used in a wide range of aircraft and other applications such as transportation systems and power generation. SEMI-SOLID FORMING OF TITANIUMALUMINIUM ALLOYS FROM ELEMENTAL POWDERS AND PROPERTIES Y.Kazuo et al. (National Industrial Research Inst., Nagoya, cJapan.l Semi-solid forming of blended clemental Ti-Al powders, at about the melting point of Al, was investigated as a function of process conditions. It is reported that materials free from pores were produced but that pores appeared during heat treatment. The volume fraction of the pores depended on the microstructure of the green compacts. Effects of heat treatment conditions on mechanical properties were studied.
36 MPR June 2000
PM2TEC’99. The following Abstracts are from papers presented at the 1999 International Conference on Powder
Powder production characterization
and
ANOMALOUS BEIIAVIOUR OF SILICON DURING ATOMIZATION S.A.Miller et ul. (Starmet Corp, USA.) The possibility of using 1 mm Si spheres, instead of wafers, to make microelectronic devices, and the use of a plasma rotating electrode process to make them, were discussed. It was noted that Si behaves in an anomalous way due to metallic, liquid, and non-metallic, solid, characteristics. Modifications to the PREP technique to make spherical Si particles were described. ECONOMICS OF PRODUCTION OF TITANIUM POWDER BY PLASMA ROTATING ELECTRODE PROCESS J.A.Isaacs et (Northeastern al. University, USA.) The need for powders of high quality for PM parts production, their high cost and the need to reduce this were discussed with regard to use of plasma rotating electrode processes for atomization. It was reported that an economic cost model had been used to identify cost centres in the PREP production of Ti powders and areas where costs could be reduced. ANALYSIS OF RAPIDLY SPINNING CUP ATOMIZATION BY IMAGE ACQUISITION TECHNIQUES S.J.Mashl. (Bodycote IMT, Inc, USA.) The rotating cup method for atomization was discussed with reference to particle morphology. The method produces fine spherical powders, and a range of other shapes. Mechanisms for melt stream fragmentation have not been identified. A method, using high speed, high magnification image capture was used to photograph the procedure under a range of operating conditions. The investigation was shown to identify mechanisms and to provide insight into powder shapes produced. PREPARATION OF TUNGSTEN POWDER WITH DISPERSED LANTIIANUM OXIDE K.Koyama et al. (Himeji University, Japan.) An investigation, using X-ray diffraction, scanning electron microscopy and electron probe microanalysis, of W powders with dispersed La,O,, made by
spray drying, thermal decomposition and H reduction, was described. The aqueous salution for spray drying contained W metatungstate and La acetate and was maintained at pH 4 to 5 by CH,COOH. The La,O, was uniformly dispersed in fine W powder. STUDIES OF GAS ATOMIZATION OF ALUMINIUM, COPPER, ZINC, TIN AND ALUMINIUM ALLOY POWDERS S.Ozbilen. (Gazi University, Turkey.) A range of non-ferrous metal and alloy powders were produced by Ar, He and N atomization using various nozzles to study the effects of these and other process parameters on particle size and particle size distribution. It was shown that the median particle size decreased as the gas:metal ratio increased. This decrease was greatest for Ar atomized powders and least for He atomized. SYNTHESIS OF TITANIUM BORIDE BY MECHANICAL ALLOYING Sijzbilen. (Gazi University, Turkey.) TiH,-B powders, in stoichiometric proportions, were mechanically alloyed in Ar, to synthesize TiB. The milled powders were characterized. The object of the study was to establish the feasibility of using mechanical alloying to synthesize compounds such as TiB. A PM APPROACH TO NON-LEAD SMALL ARMS AMMUNITION R.A.Lowden, N.L.Vaughn. (Oak Ridge National Laboratory, USA. 1 Investigations, aimed at replacing Pb in small arms ammunition, by Pbfree alloys, to avoid the health hazard to users, were described. It was suggested that the replacement materials could be made by PM and could include metal matrix composites, such as W with low melting point metals such as Sn. These could be made by sinterless consolidation and could have satisfactory mechanical properties. BULK GAS ATOMIZATION OF INJECTION MOULDING QUALITY PREALLOYED POWDERS F.Diesch. (Wideflow GmbH, Germany.) Availability of powder and its cost are noted as factors controlling the growth of MIM. It is reported that a new gas atomization process had been developed which promises to produce 10 pm powder, in bulk quantities of 1000 kg.h-‘, at low cost. First results were presented and discussed. EVALUATION OF FLOW RATE OF FINE METAL POWDERS B.Terpstra, IAnderson. Laboratory, USA. 1
(US DOE Ames
36 MPR June 2000
PM2TEC’99. The following Abstracts are from papers presented at the 1999 International Conference on Powder
Powder production characterization
and
ANOMALOUS BEIIAVIOUR OF SILICON DURING ATOMIZATION S.A.Miller et ul. (Starmet Corp, USA.) The possibility of using 1 mm Si spheres, instead of wafers, to make microelectronic devices, and the use of a plasma rotating electrode process to make them, were discussed. It was noted that Si behaves in an anomalous way due to metallic, liquid, and non-metallic, solid, characteristics. Modifications to the PREP technique to make spherical Si particles were described. ECONOMICS OF PRODUCTION OF TITANIUM POWDER BY PLASMA ROTATING ELECTRODE PROCESS J.A.Isaacs et (Northeastern al. University, USA.) The need for powders of high quality for PM parts production, their high cost and the need to reduce this were discussed with regard to use of plasma rotating electrode processes for atomization. It was reported that an economic cost model had been used to identify cost centres in the PREP production of Ti powders and areas where costs could be reduced. ANALYSIS OF RAPIDLY SPINNING CUP ATOMIZATION BY IMAGE ACQUISITION TECHNIQUES S.J.Mashl. (Bodycote IMT, Inc, USA.) The rotating cup method for atomization was discussed with reference to particle morphology. The method produces fine spherical powders, and a range of other shapes. Mechanisms for melt stream fragmentation have not been identified. A method, using high speed, high magnification image capture was used to photograph the procedure under a range of operating conditions. The investigation was shown to identify mechanisms and to provide insight into powder shapes produced. PREPARATION OF TUNGSTEN POWDER WITH DISPERSED LANTIIANUM OXIDE K.Koyama et al. (Himeji University, Japan.) An investigation, using X-ray diffraction, scanning electron microscopy and electron probe microanalysis, of W powders with dispersed La,O,, made by
spray drying, thermal decomposition and H reduction, was described. The aqueous salution for spray drying contained W metatungstate and La acetate and was maintained at pH 4 to 5 by CH,COOH. The La,O, was uniformly dispersed in fine W powder. STUDIES OF GAS ATOMIZATION OF ALUMINIUM, COPPER, ZINC, TIN AND ALUMINIUM ALLOY POWDERS S.Ozbilen. (Gazi University, Turkey.) A range of non-ferrous metal and alloy powders were produced by Ar, He and N atomization using various nozzles to study the effects of these and other process parameters on particle size and particle size distribution. It was shown that the median particle size decreased as the gas:metal ratio increased. This decrease was greatest for Ar atomized powders and least for He atomized. SYNTHESIS OF TITANIUM BORIDE BY MECHANICAL ALLOYING Sijzbilen. (Gazi University, Turkey.) TiH,-B powders, in stoichiometric proportions, were mechanically alloyed in Ar, to synthesize TiB. The milled powders were characterized. The object of the study was to establish the feasibility of using mechanical alloying to synthesize compounds such as TiB. A PM APPROACH TO NON-LEAD SMALL ARMS AMMUNITION R.A.Lowden, N.L.Vaughn. (Oak Ridge National Laboratory, USA. 1 Investigations, aimed at replacing Pb in small arms ammunition, by Pbfree alloys, to avoid the health hazard to users, were described. It was suggested that the replacement materials could be made by PM and could include metal matrix composites, such as W with low melting point metals such as Sn. These could be made by sinterless consolidation and could have satisfactory mechanical properties. BULK GAS ATOMIZATION OF INJECTION MOULDING QUALITY PREALLOYED POWDERS F.Diesch. (Wideflow GmbH, Germany.) Availability of powder and its cost are noted as factors controlling the growth of MIM. It is reported that a new gas atomization process had been developed which promises to produce 10 pm powder, in bulk quantities of 1000 kg.h-‘, at low cost. First results were presented and discussed. EVALUATION OF FLOW RATE OF FINE METAL POWDERS B.Terpstra, IAnderson. Laboratory, USA. 1
(US DOE Ames