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Development of a wax-oil-polyethylene binder for solvent debinding
with hardness and a threshold to a zone of low wear rates. A fihn was found on worn surfaces, which was characterised by electron microscopy.
Densification and properties of tungsten carbide-vanadium carbide-cobalt-aluminiu m F.J.Arenas et al. (University Inst. of Technology, Caracas, Venezuela.) Int J. Refrac. Metals~Hard Mater., Vol 19, No 4-6, 2001,381-387.
Effects of additions of up to 18wt%VC and up to 2%Al to WC-10wt%Co on sintering, properties and wear characteristics were investigated, to study synthesis of Co-AI intermetallic compounds, by vacuum sintering at 1350°C to 2500°C for one hour. Densification was improved by %Al up to 13% and higher temperature. Structures contained WC, (W,V)Cx and Co2A15. Vicker's hardness was in the range 12.8 to 17.5GPa and toughness 7.7 to 10.5MPa.ml/2. Friction decreased with increase in %VC.
Conferen Tungsten-copper alloys Sintering of tungsten-copper made from mechanically alloyed or reduced powders Y.D.Kim et al. (Agency fur Defence Development, Korea. )
W-Cu composites, for a defence application requiring high ductility under high strain rate conditions, were discussed with regard to properties, high density and uniformity of microstructure. WO3-CuO powder mixtures were high-energy ball milled and reduced in H. The powders were characterised and sintering was investigated by dilatometry. The temperature required for reduction in H was reduced by particle refinement due to milling. Full density and homogeneous microstructure were attained on sintering.
Thermal conductivity of tungsten-copper J.A.ghields et al. (CSM Industries, USA.)
It was noted that a wide range of methods can be used to make W-Cu composites for packaging of microelectronics devices and that a wide range of structures can arise. Commercially available W-Cu materials were characterised for structure and thermal conductivity that were correlated. The highest thermal conductivity was found in material made by a press-sinter-infiltrate route.
38
MPR November 2002
Application of mechanical alloying in production of tungsten carbide-cobalt-nickel R.N.Lumley, O.B.Schaffer. (University of Queensland, Australia.) PM Science/Technology Briefs, VoI 3, No 2, 2001,9-12.
It is reported that mechanical alloying had been used to process W C - C o - N i materials in order to enhance sinterability. Mechanical alloying creates a structure in which carbide and binder are intimately mixed, nanocrystalline and have a high defect density which maximise solid state sintering and reduces shrinkage. Thus, sintering temperature can be reduced and the need for sinter-HlP eliminated. W C - C o - N i has better corrosion and abrasion resistance than conventional W C Co.
Powder injection moulding Development of a wax-oil-polyethylene binder for solvent debinding
®
L.Songlin et al. (State Key Laboratory of PM, Changsha, China.) PM Technology, Vol 19, No 4, 2001, 204-207. In Chi~vese.
It is reported that a new wax-oil-polyethylene binder had been developed for injection moulding of Fe-2%Ni. Characteristics of tbe binder and solvent bebinding were investigated. Distribution of polyethylene in the binder was determined by polarisation microscopy.
Developments in injection moulded stainless steel L. Song-lin et aL (Central South University of Technology, Changsha, China.) PM h~tustry, Vol I1, No 3, 2001, 18-22. In Chinese.
Research and development into injection n, oulding of stainless steels, 316L and 17-4PH, are reviewed. Powder fabrication, binder characteristics, debinding, sintering, properties of sintered and heat-treated products and applications of injection-moulded parts are considered.
PM2TEC20m. The following abstracts are of papers presented at the 2001 International Conference on Powder Metallurgy and Particulate Materials, which was held in New Orleans, USA, in May 2001.
Deformation of sintered materials reduced thermal conductivity by increasing the pathway for conduction.
Titanium materials PM titanium technology for metal-matrix composites J.H.Moll. (Crucible Research Centre, USA.)
Use of gas atomisation to make Ti and Ti aluminide powders was outlined. Applications include jet engine parts. Production of powders and applications, including metal matrix composites, were described.
Making titanium PM cost effective S.A.MiIler. (Consultant, USA.)
The high cost of PM Ti parts was noted as an impediment to widespread application. High costs arise at all process stages. Efforts to reduce costs were reviewed with emphasis on low cost process routes for production of parts.
Production of large cost-effective PM titanium parts for military applications F.H.Froes et al. (University of Idaho, USA.)
It was noted that many military vehicles are heavy due to use of rolled steel armour plating. Weight lcan be reduced, at high cost,
by use of Ti parts. Use of PM Ti to make parts for armoured vehicles was described with examples given of shaping and ballistic performance.
Refractory metals Mechanical alloying and sintering of tungsten alloys R.Taillard et al (University of Science and Technology, Lille, France.)
Use of W alloys, in high temperature conditions, was discussed. It was noted that mechanical alloying can be used to avoid problems arising from high temperature processing. Studies of mechanically alloyed W, with Y or Y203 added, were described. Effects of size and shape of particles, dispersion of second phases and problems due to plasticity of W were investigated. Transfer of research results to part production was reported.
Injection moulding for fabrication of tungsten and rhenium parts C.Trybus et al. (Concurrent Technologies Inc., USA
Studies of injection moulding of W and Re parts were described. A wide range of material and process parameters were investigated. Re parts were produced to establish the feasibility of the methods used. Experimental and modelling results were presented.
www.metal-powder.net
Densification and properties of tungsten carbide-vanadium carbide-cobalt-aluminiu m F.J.Arenas et al. (University Inst. of Technology, Caracas, Venezuela.) Int J. Refrac. Metals~Hard Mater., Vol 19, No 4-6, 2001,381-387.
Effects of additions of up to 18wt%VC and up to 2%Al to WC-10wt%Co on sintering, properties and wear characteristics were investigated, to study synthesis of Co-AI intermetallic compounds, by vacuum sintering at 1350°C to 2500°C for one hour. Densification was improved by %Al up to 13% and higher temperature. Structures contained WC, (W,V)Cx and Co2A15. Vicker's hardness was in the range 12.8 to 17.5GPa and toughness 7.7 to 10.5MPa.ml/2. Friction decreased with increase in %VC.
Conferen Tungsten-copper alloys Sintering of tungsten-copper made from mechanically alloyed or reduced powders Y.D.Kim et al. (Agency fur Defence Development, Korea. )
W-Cu composites, for a defence application requiring high ductility under high strain rate conditions, were discussed with regard to properties, high density and uniformity of microstructure. WO3-CuO powder mixtures were high-energy ball milled and reduced in H. The powders were characterised and sintering was investigated by dilatometry. The temperature required for reduction in H was reduced by particle refinement due to milling. Full density and homogeneous microstructure were attained on sintering.
Thermal conductivity of tungsten-copper J.A.ghields et al. (CSM Industries, USA.)
It was noted that a wide range of methods can be used to make W-Cu composites for packaging of microelectronics devices and that a wide range of structures can arise. Commercially available W-Cu materials were characterised for structure and thermal conductivity that were correlated. The highest thermal conductivity was found in material made by a press-sinter-infiltrate route.
38
MPR November 2002
Application of mechanical alloying in production of tungsten carbide-cobalt-nickel R.N.Lumley, O.B.Schaffer. (University of Queensland, Australia.) PM Science/Technology Briefs, VoI 3, No 2, 2001,9-12.
It is reported that mechanical alloying had been used to process W C - C o - N i materials in order to enhance sinterability. Mechanical alloying creates a structure in which carbide and binder are intimately mixed, nanocrystalline and have a high defect density which maximise solid state sintering and reduces shrinkage. Thus, sintering temperature can be reduced and the need for sinter-HlP eliminated. W C - C o - N i has better corrosion and abrasion resistance than conventional W C Co.
Powder injection moulding Development of a wax-oil-polyethylene binder for solvent debinding
®
L.Songlin et al. (State Key Laboratory of PM, Changsha, China.) PM Technology, Vol 19, No 4, 2001, 204-207. In Chi~vese.
It is reported that a new wax-oil-polyethylene binder had been developed for injection moulding of Fe-2%Ni. Characteristics of tbe binder and solvent bebinding were investigated. Distribution of polyethylene in the binder was determined by polarisation microscopy.
Developments in injection moulded stainless steel L. Song-lin et aL (Central South University of Technology, Changsha, China.) PM h~tustry, Vol I1, No 3, 2001, 18-22. In Chinese.
Research and development into injection n, oulding of stainless steels, 316L and 17-4PH, are reviewed. Powder fabrication, binder characteristics, debinding, sintering, properties of sintered and heat-treated products and applications of injection-moulded parts are considered.
PM2TEC20m. The following abstracts are of papers presented at the 2001 International Conference on Powder Metallurgy and Particulate Materials, which was held in New Orleans, USA, in May 2001.
Deformation of sintered materials reduced thermal conductivity by increasing the pathway for conduction.
Titanium materials PM titanium technology for metal-matrix composites J.H.Moll. (Crucible Research Centre, USA.)
Use of gas atomisation to make Ti and Ti aluminide powders was outlined. Applications include jet engine parts. Production of powders and applications, including metal matrix composites, were described.
Making titanium PM cost effective S.A.MiIler. (Consultant, USA.)
The high cost of PM Ti parts was noted as an impediment to widespread application. High costs arise at all process stages. Efforts to reduce costs were reviewed with emphasis on low cost process routes for production of parts.
Production of large cost-effective PM titanium parts for military applications F.H.Froes et al. (University of Idaho, USA.)
It was noted that many military vehicles are heavy due to use of rolled steel armour plating. Weight lcan be reduced, at high cost,
by use of Ti parts. Use of PM Ti to make parts for armoured vehicles was described with examples given of shaping and ballistic performance.
Refractory metals Mechanical alloying and sintering of tungsten alloys R.Taillard et al (University of Science and Technology, Lille, France.)
Use of W alloys, in high temperature conditions, was discussed. It was noted that mechanical alloying can be used to avoid problems arising from high temperature processing. Studies of mechanically alloyed W, with Y or Y203 added, were described. Effects of size and shape of particles, dispersion of second phases and problems due to plasticity of W were investigated. Transfer of research results to part production was reported.
Injection moulding for fabrication of tungsten and rhenium parts C.Trybus et al. (Concurrent Technologies Inc., USA
Studies of injection moulding of W and Re parts were described. A wide range of material and process parameters were investigated. Re parts were produced to establish the feasibility of the methods used. Experimental and modelling results were presented.
www.metal-powder.net