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Correlations between isostatic press parameters and characteristics of ceramic parts
identiEed. Some liquid is forced to the edge of the nozzle and is broken up by the gas flow. The remainder is less energetically disintegrated in the low speed wake. It was suggested that this may explain the wide particle size distribution found in some atomized powders.
High performance
materials
OPTIMIZATION OF SINTERING PARAMETERS FOR HIGH STRENGTH LOW ALLOY STEELS R.M. German et al. (Pennsylvania State University, Pennsylvania, USA) A study of processing Fe alloyed with Cu, Ni, MO and C was undertaken with the object of optimizing process conditions for enhanced properties at densities of about 7.1 gm.cm-‘. The need for identification of key parameters was emphasized and a variable search method was used to this end. These parameters were closely controlled and tolerances in others were broadened in order to reduce costs without loss in final properties SYNERGIES OF HIGH TEMPERATURE SINTERING AND ALLOY DEVELOPMENT FOR PM POWERTRAIN PARTS R.Shivanath, P.K.Jones. (Stackpole Ltd, Oakville, Canada.) High temperature sinterlng of parts was reviewed with reference to costs, properties and dimensional changes. The trend away from high temperature sir&ring was noted. It was argued that an advantage of high temperature sinterlng, alloying freedom, had been overlooked and that good alloying, together with good densification, was critically important. High temperature sintering was considered to be an important factor in the drive to replace steel parts with PM components. The Fe-Mn-C system was described. This system was reported to been used in a range of highly stressed automotive parts. DEVELOPMENT OF HIGH STRENGTH STEELS BY NBW ALLOYING AND SINTERJNG TECBNIQIJES E.Emst et al. (Sintermetallwerk Krebsoge GmbH, Radevormwald, Germany.) The need to avoid the use of free Ni, for environmental reasons, was noted. The elimination of free Ni powder from PM by use of prealloyed powders was discussed with reference to material properties. Alloying of a range of steel powders with Ni was investigated as a function of mechanical and fatigue The studies were properties. finalized with the production of an automotive part.
42 MPR March 1997
Warm compaction EFFECTS OF REPRESSING ON PROPERTIES OF WABM COMPACTED MATERIALS SYSTEMS S.R.Sun, K.R.Crouchman. (Pennsylvania Pressed Metals Inc., USA) Static and dynamic mechanical properties of warm compacted doublepressed/double sintered materials were discussed. Experiments intended to attain steel densities in excess of 7.55 gm.cmm3 were described.
Novel materials SCANDIUM OXYCARBIDE A NOVEL COMPONENT FOR BARD MATERIALS GRoiss et al. (Technical University, Vienna, Austria.) Scandium oxycarbide, Scz (0,C) , the carbide and oxide were discussed with reference to possible use as a constituent of hardmetals. It is noted that the existence of Scz(O,C) has been disputed but it is reported that the hardness of ‘DC is increased from 31 to over 50 GPa by small additions of Scz(O,C). It is suggested that the compound has a wide range of composition with a cubic structure and that Sc(O,N,C) could improve wear resistance of cemented carbides. ALUMINJUM NITRIDE-TUNGSTEN COMPOSITIONALLY GRADED MATERIAL FOR THERMAL BARRIER USE R.Watanabe et al. (Tohoku University, Sendai, Japan.) It was reported that an AlN/W compositionally graded material had been fabricated, layer-by-layer, from 1.39 pm AlN and 5.3 pm W powders, by HIP to full density at 200 MPa and 1850°C. Testing for thermal shock damage was monitored by accoustic emission techniques. The material was shown to have good thermal shock resistance and heat shield properties. STRUCTURAL EVOLUTION DURING SINTERING AND DIFFUSION OF COMPOSITIONALLY GRADED MATERIALS S.C.Yang. (Mando Machinery Corporation, Korea.) It was suggested that compositionally graded Fe/WC-Co materials could be used for wear resistant parts. Specimens were made by pressing and sintering and characterized for microstructure. The material was shown to have good potential for cost effective parts.
CORRELATIONS BETWEEN ISOSTATIC PRESS PARAMETERS AND CHARACTERISTICS OF CERAMIC PARTS C.S.Dumitrn, S,Sever. (University of Craiova, Romania.) Researches into production of parts from transluscent polycrystalline A120s, with respect to correlations between automatic isostatic pressing parameters and characteristics of pressed parts, were described. Optimum process conditions were established and outlined.
Refractory metal composites EFFECT OF COPPER PARTICLE SIZE ON SINTERING OF METAL INJECTION MOULDED TUNGSTEN-COPPER I.H.Moon et al. (Hanyang University, Korea.) The effect of Cu powder particle size on sintering of MIM W-Cu parts was investigated. Milled and mixed powders were compared. A range of Cu powders was used and simntering was evaluated in terms of Cu powder characteristics. The best sintering was attained with fine Cu powder giving densities in excess of 98%. THERMOMECHANICAL PROCESSING OF SINTERED TUNGSTEN-COPPER COMPOSITES EKOhrlner, B.Bryskin. (Oak Ridge National Laboratory, USA.) Properties of W-Cu alloys were discussed with respect to the need for high density and a structure comprising a continuous Cu matrix with W particles. Methods to attain this state, liqiud phase sintering, iniiltration, and these in combination, HIP and MIM, were outlined and it was noted that these do not always reach high density. Thermomechanical processing, to make W4O%Cu with high density, was investigated with regard to structural evolution. It was reported that hot extrusion gave material with high density.
Dimensional OM parts
control of
EFFECT OF SINTERING ON VARIATIONS IN PART DIMENSIONS AVavan et al. (Laval University, Canada) Literature on dimensional control of PM parts was reviewed, A statistical study, in a production environment, of the effects of green density, material and sintering parameters on dimensional variation in parts was described after which alterations were made to process conditions with a further evaluation. It was reported that the procedure could result in the attainment of closer dimensional tolerances.
High performance
materials
OPTIMIZATION OF SINTERING PARAMETERS FOR HIGH STRENGTH LOW ALLOY STEELS R.M. German et al. (Pennsylvania State University, Pennsylvania, USA) A study of processing Fe alloyed with Cu, Ni, MO and C was undertaken with the object of optimizing process conditions for enhanced properties at densities of about 7.1 gm.cm-‘. The need for identification of key parameters was emphasized and a variable search method was used to this end. These parameters were closely controlled and tolerances in others were broadened in order to reduce costs without loss in final properties SYNERGIES OF HIGH TEMPERATURE SINTERING AND ALLOY DEVELOPMENT FOR PM POWERTRAIN PARTS R.Shivanath, P.K.Jones. (Stackpole Ltd, Oakville, Canada.) High temperature sinterlng of parts was reviewed with reference to costs, properties and dimensional changes. The trend away from high temperature sir&ring was noted. It was argued that an advantage of high temperature sinterlng, alloying freedom, had been overlooked and that good alloying, together with good densification, was critically important. High temperature sintering was considered to be an important factor in the drive to replace steel parts with PM components. The Fe-Mn-C system was described. This system was reported to been used in a range of highly stressed automotive parts. DEVELOPMENT OF HIGH STRENGTH STEELS BY NBW ALLOYING AND SINTERJNG TECBNIQIJES E.Emst et al. (Sintermetallwerk Krebsoge GmbH, Radevormwald, Germany.) The need to avoid the use of free Ni, for environmental reasons, was noted. The elimination of free Ni powder from PM by use of prealloyed powders was discussed with reference to material properties. Alloying of a range of steel powders with Ni was investigated as a function of mechanical and fatigue The studies were properties. finalized with the production of an automotive part.
42 MPR March 1997
Warm compaction EFFECTS OF REPRESSING ON PROPERTIES OF WABM COMPACTED MATERIALS SYSTEMS S.R.Sun, K.R.Crouchman. (Pennsylvania Pressed Metals Inc., USA) Static and dynamic mechanical properties of warm compacted doublepressed/double sintered materials were discussed. Experiments intended to attain steel densities in excess of 7.55 gm.cmm3 were described.
Novel materials SCANDIUM OXYCARBIDE A NOVEL COMPONENT FOR BARD MATERIALS GRoiss et al. (Technical University, Vienna, Austria.) Scandium oxycarbide, Scz (0,C) , the carbide and oxide were discussed with reference to possible use as a constituent of hardmetals. It is noted that the existence of Scz(O,C) has been disputed but it is reported that the hardness of ‘DC is increased from 31 to over 50 GPa by small additions of Scz(O,C). It is suggested that the compound has a wide range of composition with a cubic structure and that Sc(O,N,C) could improve wear resistance of cemented carbides. ALUMINJUM NITRIDE-TUNGSTEN COMPOSITIONALLY GRADED MATERIAL FOR THERMAL BARRIER USE R.Watanabe et al. (Tohoku University, Sendai, Japan.) It was reported that an AlN/W compositionally graded material had been fabricated, layer-by-layer, from 1.39 pm AlN and 5.3 pm W powders, by HIP to full density at 200 MPa and 1850°C. Testing for thermal shock damage was monitored by accoustic emission techniques. The material was shown to have good thermal shock resistance and heat shield properties. STRUCTURAL EVOLUTION DURING SINTERING AND DIFFUSION OF COMPOSITIONALLY GRADED MATERIALS S.C.Yang. (Mando Machinery Corporation, Korea.) It was suggested that compositionally graded Fe/WC-Co materials could be used for wear resistant parts. Specimens were made by pressing and sintering and characterized for microstructure. The material was shown to have good potential for cost effective parts.
CORRELATIONS BETWEEN ISOSTATIC PRESS PARAMETERS AND CHARACTERISTICS OF CERAMIC PARTS C.S.Dumitrn, S,Sever. (University of Craiova, Romania.) Researches into production of parts from transluscent polycrystalline A120s, with respect to correlations between automatic isostatic pressing parameters and characteristics of pressed parts, were described. Optimum process conditions were established and outlined.
Refractory metal composites EFFECT OF COPPER PARTICLE SIZE ON SINTERING OF METAL INJECTION MOULDED TUNGSTEN-COPPER I.H.Moon et al. (Hanyang University, Korea.) The effect of Cu powder particle size on sintering of MIM W-Cu parts was investigated. Milled and mixed powders were compared. A range of Cu powders was used and simntering was evaluated in terms of Cu powder characteristics. The best sintering was attained with fine Cu powder giving densities in excess of 98%. THERMOMECHANICAL PROCESSING OF SINTERED TUNGSTEN-COPPER COMPOSITES EKOhrlner, B.Bryskin. (Oak Ridge National Laboratory, USA.) Properties of W-Cu alloys were discussed with respect to the need for high density and a structure comprising a continuous Cu matrix with W particles. Methods to attain this state, liqiud phase sintering, iniiltration, and these in combination, HIP and MIM, were outlined and it was noted that these do not always reach high density. Thermomechanical processing, to make W4O%Cu with high density, was investigated with regard to structural evolution. It was reported that hot extrusion gave material with high density.
Dimensional OM parts
control of
EFFECT OF SINTERING ON VARIATIONS IN PART DIMENSIONS AVavan et al. (Laval University, Canada) Literature on dimensional control of PM parts was reviewed, A statistical study, in a production environment, of the effects of green density, material and sintering parameters on dimensional variation in parts was described after which alterations were made to process conditions with a further evaluation. It was reported that the procedure could result in the attainment of closer dimensional tolerances.