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Plastic and elastic behaviour of submicron and micron grades of tungsten carbide-cobalt
properties of conventional Sn alloys were compared.
Metal injection
and reduced
moulding
CONTROL OF SURFACE LAYER THICKNESS IN METAL CO-INJECTION MOULDING J.R.Alcock et al. icranfield University, UK. ) Metal co-injection moulding was described. This allows parts to be made from different alloys by using a doublebarrelled injection moulding machine from which two feedstocks are injected successively. Material from the first forms the skin and the core is formed from the second barrel. Finite element model predictions of skin/core thickness ratio were compared with experimental measurements. RHEOLOGICAL PROPERTIES OF INJECTION MOULDING FEEDSTOCKS S.Saritas, C.Karatas. (Gazi University, Ankara, Turkey.) The rheological properties of a range of feedstocks prepared from a paraffin wax-35% polypropylene5%tearic acid binder were investigated. Metal and ceramic powders of various sizes and shapes in varying concentrations were used. For each feedstock critical solids loadings, moulding temperatures and pressures were established. As particle shape became closer to spherical and particle size decreased possible solids loading increased.
EFFECT OF BINDER COMPOSITION ON PROPERTIES OF INJECTION MOULDED STAINLESS STEEL
port, uses.
R.Ibrahim et al. (Sirim Berhad, Selangor, Malaysia. 1 A study of the effects of binder composition on properties of sintered injection moulded 316L stainless steel was described. The binders were based on paraffin wax-polypropylene-stearic acid in three formulations. Specimens were injection moulded, thermally debound and sintered in H. Structures and mechanical properties were determined and results discussed.
SINTERING OF TITANIUM ALLOYS MADE FROM BLENDED MASTER ALLOY POWDERS
INFLUENCE OF FEEDSTOCK HOMOGENEITY ON DEBINDING OF INJECTION MOULDED PARTS L.M.Rezendi. M.C.Fredel, (UFSC, Florianopolis, Brazil.) Investigations of the effects of feedstock homogeneity on debinding of injection moulded carbonyl Fe parts were described. The feedstocks, mixed for various lengths of time, contained 92.8wt%Fe. The binder was made up of paraffin wax, polypropylene and additives. Solvent and thermal debinding were used successively and materials were sintered. Porosity was measured after sintering. Results showing effects of different homogeneity levels were presented. Dimensional stability, related to mixing performance, was discussed. Light
alloys
EFFECT OF SURFACE ACTIVE ADDITIVES ON RHEOLOGY OF STAINLESS STEEL FEEDSTOCK
SINTERING OF HIGH STRENGTH ALUMINIUM ALLOYS TO CONTROLLED DIMENSIONS
L.Nyborg et al. (Chalmers University of Technology, Goteborg, Sweden.) An investigation of the influence of surface active additives on the rheological properties of 316L stainless steel injection moulding feedstocks was described. Adsorption onto powder surfaces was studied by electron microscopy. Effects of molecular weight of additives with the same active group were determined as well as the effect of different active groups.
H.Danninger et al. (Technical University, Vienna, Austria.) It was noted that Al alloys of the ‘ixxx, Al-Mg-Zn-Cu, type are difficult to sinter to close dimensional tolerances due to swelling. Sintering of these alloys was discussed. It was shown that by selection of powders dimensional stability could be attained. The Al-Mg-Zn-Cu alloys have higher mechanical properties than Al-Cu-Mg-Si alloys, reaching 400 MPa after heat treatment.
FABRICATION AND PROPERTIES OF INJECTION MOULDED HARDMETAL PARTS
PRODUCTION OF ALUMINIUM FOAM BY PM AND APPLICATIONS
M.S.Raduta, R.F.Singer. (University of Erlangen-Ndrnberg, Erlangen, Germany.) Results of investigations on the production of hardmetal parts by injection moulding were presented. Optimization of feedstock composition, debinding conditions and control of C content were studied. 40
MPR April 1999
et al. (Schunk SinterF.Baumgartner metalltechnik GmbH, Heuchelheim, Germany.) Production of foamed Al material was discussed with consideration of the form of material (bar, sheet, etc.), foam clad with Al or steel layers and use of preformed foamable materials. The objective was to introduce new, lightweight, structural materials for trans-
civil
engineering
and
building
J.Bolton, B.S.Becker. (University of Bradford, Bradford, Yorkshire, UK.) It was reported that 95% density had been attained in near homogeneous dual phase Ti-G%Al-4%V alloys. These were made from Ti sponge and an Al-V master alloy by sintering at 1250°C. Phase reactions during sintering were studied at temperatures above 600°C. Al diffused into Ti and formed aluminide phases. Densification was mainly by solid state diffusion.
Ward materials PLASTIC AND ELASTIC BEHAVIOUR OF SUBMICRON AND MICRON GRADES OF TUNGSTEN CARBIDECOBALT et al. (University of S.Luyckx Witwatersrand, Wits, South Africa.) Mechanical properties of 2 WC-(6 to 15)wt%Co alloys were investigated. Alloys were prepared from WC with particle sizes of 0.4 pm and 1-2 pm. Mechanical tests were at ambient temperature up to 1000°C. PREPARATION OF ULTRAFINE TITANIUM CARBIDE-NICKEL BASED CERMET BY MECHANICAL ALLOYING A.Sugiyama et al. (National Industrial Research Inst of Nagoya, Nagoya, Japan.) Production of a Ni-TiC cermet by mechanical alloying and spark plasma sintering was investigated. A range of Ni-Ti-C powders were mechanically alloyed during which non-stoichiometric TiC was synthesized. Additional Ni and C powders were added to make the composition Tic-20wt%Ni, which was then sintered at 800°C. The sintered alloy comprised TIC, Ni and a Ni-Ti alloy. TiC particles were less than 1 pm in size and were homogeneously distributed. SYNTHESIS OF TITANIUM CARBIDENICKEL-MOLYBDENUM CERMET BY MECHANICAL ALLOYING C.J.Choi, W.W.Park. (Korea Inst. of Machinery and Materials, Kyungnam, S.Korea.) Mechanical alloying was used to process elemental Ti-C-Ni-Mo powder mixtures. Milled powder contained ultrafine TIC particles and amorphous Ti-Ni phases according to milling conditions. After sintering the alloys contained TIC particles 0.1 to 1.0 pm in size in a Ni-Mo matrix. The paper
Metal injection
and reduced
moulding
CONTROL OF SURFACE LAYER THICKNESS IN METAL CO-INJECTION MOULDING J.R.Alcock et al. icranfield University, UK. ) Metal co-injection moulding was described. This allows parts to be made from different alloys by using a doublebarrelled injection moulding machine from which two feedstocks are injected successively. Material from the first forms the skin and the core is formed from the second barrel. Finite element model predictions of skin/core thickness ratio were compared with experimental measurements. RHEOLOGICAL PROPERTIES OF INJECTION MOULDING FEEDSTOCKS S.Saritas, C.Karatas. (Gazi University, Ankara, Turkey.) The rheological properties of a range of feedstocks prepared from a paraffin wax-35% polypropylene5%tearic acid binder were investigated. Metal and ceramic powders of various sizes and shapes in varying concentrations were used. For each feedstock critical solids loadings, moulding temperatures and pressures were established. As particle shape became closer to spherical and particle size decreased possible solids loading increased.
EFFECT OF BINDER COMPOSITION ON PROPERTIES OF INJECTION MOULDED STAINLESS STEEL
port, uses.
R.Ibrahim et al. (Sirim Berhad, Selangor, Malaysia. 1 A study of the effects of binder composition on properties of sintered injection moulded 316L stainless steel was described. The binders were based on paraffin wax-polypropylene-stearic acid in three formulations. Specimens were injection moulded, thermally debound and sintered in H. Structures and mechanical properties were determined and results discussed.
SINTERING OF TITANIUM ALLOYS MADE FROM BLENDED MASTER ALLOY POWDERS
INFLUENCE OF FEEDSTOCK HOMOGENEITY ON DEBINDING OF INJECTION MOULDED PARTS L.M.Rezendi. M.C.Fredel, (UFSC, Florianopolis, Brazil.) Investigations of the effects of feedstock homogeneity on debinding of injection moulded carbonyl Fe parts were described. The feedstocks, mixed for various lengths of time, contained 92.8wt%Fe. The binder was made up of paraffin wax, polypropylene and additives. Solvent and thermal debinding were used successively and materials were sintered. Porosity was measured after sintering. Results showing effects of different homogeneity levels were presented. Dimensional stability, related to mixing performance, was discussed. Light
alloys
EFFECT OF SURFACE ACTIVE ADDITIVES ON RHEOLOGY OF STAINLESS STEEL FEEDSTOCK
SINTERING OF HIGH STRENGTH ALUMINIUM ALLOYS TO CONTROLLED DIMENSIONS
L.Nyborg et al. (Chalmers University of Technology, Goteborg, Sweden.) An investigation of the influence of surface active additives on the rheological properties of 316L stainless steel injection moulding feedstocks was described. Adsorption onto powder surfaces was studied by electron microscopy. Effects of molecular weight of additives with the same active group were determined as well as the effect of different active groups.
H.Danninger et al. (Technical University, Vienna, Austria.) It was noted that Al alloys of the ‘ixxx, Al-Mg-Zn-Cu, type are difficult to sinter to close dimensional tolerances due to swelling. Sintering of these alloys was discussed. It was shown that by selection of powders dimensional stability could be attained. The Al-Mg-Zn-Cu alloys have higher mechanical properties than Al-Cu-Mg-Si alloys, reaching 400 MPa after heat treatment.
FABRICATION AND PROPERTIES OF INJECTION MOULDED HARDMETAL PARTS
PRODUCTION OF ALUMINIUM FOAM BY PM AND APPLICATIONS
M.S.Raduta, R.F.Singer. (University of Erlangen-Ndrnberg, Erlangen, Germany.) Results of investigations on the production of hardmetal parts by injection moulding were presented. Optimization of feedstock composition, debinding conditions and control of C content were studied. 40
MPR April 1999
et al. (Schunk SinterF.Baumgartner metalltechnik GmbH, Heuchelheim, Germany.) Production of foamed Al material was discussed with consideration of the form of material (bar, sheet, etc.), foam clad with Al or steel layers and use of preformed foamable materials. The objective was to introduce new, lightweight, structural materials for trans-
civil
engineering
and
building
J.Bolton, B.S.Becker. (University of Bradford, Bradford, Yorkshire, UK.) It was reported that 95% density had been attained in near homogeneous dual phase Ti-G%Al-4%V alloys. These were made from Ti sponge and an Al-V master alloy by sintering at 1250°C. Phase reactions during sintering were studied at temperatures above 600°C. Al diffused into Ti and formed aluminide phases. Densification was mainly by solid state diffusion.
Ward materials PLASTIC AND ELASTIC BEHAVIOUR OF SUBMICRON AND MICRON GRADES OF TUNGSTEN CARBIDECOBALT et al. (University of S.Luyckx Witwatersrand, Wits, South Africa.) Mechanical properties of 2 WC-(6 to 15)wt%Co alloys were investigated. Alloys were prepared from WC with particle sizes of 0.4 pm and 1-2 pm. Mechanical tests were at ambient temperature up to 1000°C. PREPARATION OF ULTRAFINE TITANIUM CARBIDE-NICKEL BASED CERMET BY MECHANICAL ALLOYING A.Sugiyama et al. (National Industrial Research Inst of Nagoya, Nagoya, Japan.) Production of a Ni-TiC cermet by mechanical alloying and spark plasma sintering was investigated. A range of Ni-Ti-C powders were mechanically alloyed during which non-stoichiometric TiC was synthesized. Additional Ni and C powders were added to make the composition Tic-20wt%Ni, which was then sintered at 800°C. The sintered alloy comprised TIC, Ni and a Ni-Ti alloy. TiC particles were less than 1 pm in size and were homogeneously distributed. SYNTHESIS OF TITANIUM CARBIDENICKEL-MOLYBDENUM CERMET BY MECHANICAL ALLOYING C.J.Choi, W.W.Park. (Korea Inst. of Machinery and Materials, Kyungnam, S.Korea.) Mechanical alloying was used to process elemental Ti-C-Ni-Mo powder mixtures. Milled powder contained ultrafine TIC particles and amorphous Ti-Ni phases according to milling conditions. After sintering the alloys contained TIC particles 0.1 to 1.0 pm in size in a Ni-Mo matrix. The paper