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Industrial applications of iron aluminide
Production of graded metallic filter by wet powder spraying M.Bram et al. (Forschungzentrum }Lilich GmbH, JiJlich, Germany.) Properties of metallic filters for microfiltration were reviewed. It was shown that a graded porous structure can be made by spraying a metal powder suspension onto a coarse porous support system. Production of a microfilter using 316L stainless steel powder, with particle sizes smaller than 2ram made by a wire electro-explosion technique, was described. The filter was characterised by microscopy and permeability measurement.
Porous metallic materials made with pore-forming agents L.l.Chernyshev. (Inst. for Problems of Materials Science, Kiev, Ukraine.) Properties of porous materials made using pore-forming agents were reviewed. It was shown that pressing and sintering, physical and mechanical properties depend on correlation between particle sizes of metal powders and pore forming materials.
Magnetic and electrical chemncats Experimental and numerical study of ferrlte slurry compaction F.Toussaint et al. (Inst. National Polytechnique de Grenoble, Grenoble, France.) The behaviour of ferrite slurries was investigated to carry out numerical simulation of magnet manufacture. Parameters of an elasto-plastic model were identified, considering the slurry as a monoplastic material. Comparison of a local density map with me:lsured local densities was used to predict density gradients in a green body. A diphasic approach, treating the slurry as a mixture of two phases, is proposed for improvement of the simulation.
Improvement of coerclvity of ferrlte materials by additions of lanthanum end cobalt A.Morel et al. (Ferroxdure, Evreux, France.) It was reported that the addition of La and Co to 5r-Fe-O ferrites increased coercivity due to the increased anisotropy field. It was shown that where x is greater than 0.25 in Srl"XFe12-xCoxLaxO19 coercivity deteriorated. Grain growth during processing and interactions between constituents were
metal-powder.net
investigated. Improved magnets were obtained by optimisation of ceramic factors.
Use of precipitated ferrlte powders In manufacture of enlsotropic sintered magnets D.Rodrigues, S.Janasi. (inst. for Technological Research, Sao Paulo, Brazil.)
Fe aluminide materials were discussed. It was noted that poor ductility at ambient temperatures has limited their use. It was reported that a new reinforced PM grade, FeA140grade 3, Fe-24wt%Al.O.11%Zr15wtppm B, had been developed. This makes use of grain boundary strengthening. Properties of the alloy were described.
Production of ferrite magnets from Fe oxides and Ba and Sr carbonates was described. Part of this ceramic process involves milling to particles consisting of a single magnetic domain, which can be oriented before compaction to give anisotropy in properties. It was shown that co-precipitation gives very fine particles which can give magnets with improved properties. Use of co-precipitated powders was investigated. Powders, of optimised Fe:Ba ratio, were aligned in a magnetic field, pressed and sintered. Microstructures and magnetic properties were evaluated.
Fabrication end properties of titanium elumlnldes P.Belague et al. (Turbomeca, (Snecma Group), Bordes, France.)
Anneal hardening effect In slntered copper nLLoya D.Tancic, S.Nestorovic. (University of Belgrade, Bor, Yugoslavia.)
Comparison of properties of powders made by p s atomlsetlon and rotating electrode process M.Thomas, F.Popoff. (National Office for Aerospace Research, Chatillon, France.)
Cu, Cu-Zn, Cu-Ni and Cu-Ni-Sn alloys were pressed and sintered from powders and cold rolled by 30, 50 and 70%. The cold rolled alloys were isochronally annealed up to the recrystallisation range and hardness and electrical resistivity measured. It was found that there is a hardening effect in the range 180°C to 400°C,
Quality of tunpten powder based electrical contacts made by Isostatlc pressing l.Pascu et al. (University of Craiova, Craiova, Roamania.) An experimental and theoretical study of electrical contacts, made from W powder by isostatic pressing, was described. Three types of W powder, differing in particle size distribution, were compacted at three hydrostatic pressures. Comparison was made between all the samples for hardness, density, resistivity and structure and also with die pressed specimens.
SuperaUoys and . intermetalUc materials Industrial applications of Iron alumlnlde A.Schwaiger eta, (Plansee GmbH, Lechbruck, Germany.)
Ti aluminides were reviewed with regard to properties, applications and poor ambient temperature ductility. It was reported that gas atomised Ti-48at%A1-2%Cr2%Nb powders had been consolidated to full density by hot isostatic pressing. Effects of HIP and heat treatment on structure and mechanical properties w e r e discussed with emphasis on fatigue related to microstructural defects. Future engine applications were considered.
Prealloyed powders of Ti-49at%Al2%Cr-2%Nb were made by gas atomisalion or by REP. Powders were characterised to compare properties and to evaluate factors limiting their use. Chemical heterogeneities and interstitial contamination were found to arise in non-optimised PM processing. Mechanical properties of samples made from different size fractions from both types of powder were compared. The importance of good chemical homogeneity was emphasised.
Current status of technololly of PM superaUoy discs for p a turbine anilines G.S.Garibov.(All Russian Inst. for Light Alloys, Moscow, Russia.) It was reported that large numbers of discs and shafts for gas turbine engines had been produced and operated satisfactorily. Improvements in processing were reviewed, such as production of powders with improved purity, lower powder particle sizes and use of automated quality control leading to greater consistency of properties. Coupled with design improvements costs were shown to be lower.
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39
Porous metallic materials made with pore-forming agents L.l.Chernyshev. (Inst. for Problems of Materials Science, Kiev, Ukraine.) Properties of porous materials made using pore-forming agents were reviewed. It was shown that pressing and sintering, physical and mechanical properties depend on correlation between particle sizes of metal powders and pore forming materials.
Magnetic and electrical chemncats Experimental and numerical study of ferrlte slurry compaction F.Toussaint et al. (Inst. National Polytechnique de Grenoble, Grenoble, France.) The behaviour of ferrite slurries was investigated to carry out numerical simulation of magnet manufacture. Parameters of an elasto-plastic model were identified, considering the slurry as a monoplastic material. Comparison of a local density map with me:lsured local densities was used to predict density gradients in a green body. A diphasic approach, treating the slurry as a mixture of two phases, is proposed for improvement of the simulation.
Improvement of coerclvity of ferrlte materials by additions of lanthanum end cobalt A.Morel et al. (Ferroxdure, Evreux, France.) It was reported that the addition of La and Co to 5r-Fe-O ferrites increased coercivity due to the increased anisotropy field. It was shown that where x is greater than 0.25 in Srl"XFe12-xCoxLaxO19 coercivity deteriorated. Grain growth during processing and interactions between constituents were
metal-powder.net
investigated. Improved magnets were obtained by optimisation of ceramic factors.
Use of precipitated ferrlte powders In manufacture of enlsotropic sintered magnets D.Rodrigues, S.Janasi. (inst. for Technological Research, Sao Paulo, Brazil.)
Fe aluminide materials were discussed. It was noted that poor ductility at ambient temperatures has limited their use. It was reported that a new reinforced PM grade, FeA140grade 3, Fe-24wt%Al.O.11%Zr15wtppm B, had been developed. This makes use of grain boundary strengthening. Properties of the alloy were described.
Production of ferrite magnets from Fe oxides and Ba and Sr carbonates was described. Part of this ceramic process involves milling to particles consisting of a single magnetic domain, which can be oriented before compaction to give anisotropy in properties. It was shown that co-precipitation gives very fine particles which can give magnets with improved properties. Use of co-precipitated powders was investigated. Powders, of optimised Fe:Ba ratio, were aligned in a magnetic field, pressed and sintered. Microstructures and magnetic properties were evaluated.
Fabrication end properties of titanium elumlnldes P.Belague et al. (Turbomeca, (Snecma Group), Bordes, France.)
Anneal hardening effect In slntered copper nLLoya D.Tancic, S.Nestorovic. (University of Belgrade, Bor, Yugoslavia.)
Comparison of properties of powders made by p s atomlsetlon and rotating electrode process M.Thomas, F.Popoff. (National Office for Aerospace Research, Chatillon, France.)
Cu, Cu-Zn, Cu-Ni and Cu-Ni-Sn alloys were pressed and sintered from powders and cold rolled by 30, 50 and 70%. The cold rolled alloys were isochronally annealed up to the recrystallisation range and hardness and electrical resistivity measured. It was found that there is a hardening effect in the range 180°C to 400°C,
Quality of tunpten powder based electrical contacts made by Isostatlc pressing l.Pascu et al. (University of Craiova, Craiova, Roamania.) An experimental and theoretical study of electrical contacts, made from W powder by isostatic pressing, was described. Three types of W powder, differing in particle size distribution, were compacted at three hydrostatic pressures. Comparison was made between all the samples for hardness, density, resistivity and structure and also with die pressed specimens.
SuperaUoys and . intermetalUc materials Industrial applications of Iron alumlnlde A.Schwaiger eta, (Plansee GmbH, Lechbruck, Germany.)
Ti aluminides were reviewed with regard to properties, applications and poor ambient temperature ductility. It was reported that gas atomised Ti-48at%A1-2%Cr2%Nb powders had been consolidated to full density by hot isostatic pressing. Effects of HIP and heat treatment on structure and mechanical properties w e r e discussed with emphasis on fatigue related to microstructural defects. Future engine applications were considered.
Prealloyed powders of Ti-49at%Al2%Cr-2%Nb were made by gas atomisalion or by REP. Powders were characterised to compare properties and to evaluate factors limiting their use. Chemical heterogeneities and interstitial contamination were found to arise in non-optimised PM processing. Mechanical properties of samples made from different size fractions from both types of powder were compared. The importance of good chemical homogeneity was emphasised.
Current status of technololly of PM superaUoy discs for p a turbine anilines G.S.Garibov.(All Russian Inst. for Light Alloys, Moscow, Russia.) It was reported that large numbers of discs and shafts for gas turbine engines had been produced and operated satisfactorily. Improvements in processing were reviewed, such as production of powders with improved purity, lower powder particle sizes and use of automated quality control leading to greater consistency of properties. Coupled with design improvements costs were shown to be lower.
March 2003 ~
39