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Consolidation of ball milled aluminium alloy-silicon carbide composite powders
Pressing EFFECTS OF WALL FRICTION ON EJECTION OF PRESSED CERAMIC PARTS S.L.Rough. (Imperial B.J.Briscoe, College, London, UK.) Powder TechnoZ., Vol98, No 3,1998,228-233. Forces required to eject compacted ceramic parts from a rigid die were investigated with regard to die wall friction. Results for ejection of compacts made from agglomerated Also, powder under lubricated and dry conditions are presented. Without lubricant a stick-slip effect was found. Effects of compact aspect ratio, applied compaction force and ejection speed were considered. Ejection force depended on friction and increased with aspect ratio, compaction load and absence or presence of lubricant.
Sintering DISTRIBUTION OF ELECTRIC CURRFNT PATH AND TEMPERATURE IN SPARE SINTERING H.Watanabe et al. (Kagawa Industrial Technology Centre, Takamoto, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 10,1997,974-979. (In Japanese.) Spark sintering of Cu and AlzO, powders in graphite and insulating dies was investigated with reference to electric current paths. In the case of Cu in graphite dies almost all the current passed through the specimen. When the current was pulsed it also passed through the die and resulted in temperature variations in the sample. In the insulated die current passed through the graphite punches and the Cu and there was significant temperature fluctuation. With A&O, in graphite die and punches current passed through the graphite and there was considerable temperature variation in the samples.
Fundamentals PRODUCING FINE DROPLETS OF WATER BY TWIN FLUID ATOMIZATION D.A.Nguyen, M.J.Rhodes. (Monash University, Australia.) Powder Technol., Vol98, No 3, 1998,285-292. Atomization in two-fluid, air-water, atomizers, was investigated. Two atomizer nozzles are compared. One had internal mixing of the two fluids. In the 38
MPR May 1999
other, of novel design, the fluids were ejected through separate nozzles. Droplet sizes were measured as a function of the water:air ratio. Pressure drops were determined. SIZING TECHNIQUE FOR FINE POWDER DISPERSED IN AIR Y.Kousaka et al. (Osaka Prefecture University, Sakai, Japan.). Powder Technol., Vol 100, No 1,1998, 15-19. It is reported that a fine particle sizing technique had been developed in which a differential mobility analyser is combined with a condensation nucleus counter. A boiling method is used to break up aggregates into primary particles. The technique was applied to a range of powders including non-spherical and tightly agglomerated particles.
pressure of 375 MPa, contained amorphous and crystalline phases in an Sn rich matrix. CONSOLIDATION OF BALL MILLED ALUMINIUM ALLOY-SILICON CARBIDE COMPOSITE POWDERS M.S.El-Eskandarany et al. (Al-Ahzar University, Cairo, Egypt.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 10, 1997,1143-1147. (In English.) Al-lvol%(Ti, MO, Cul-BO%SiC powders were ball milled and the resulting nanocrystalline powders were consolidated by plasma activated sintering. Powders and compacts were characterized for structure, composition, hardness and density.
Iron and steel
APPLICATION OF IMAGE ANALYSIS TO EVALUATION OF POWDER PARTICLE MORPHOLOGY
VIBRATION OF SINTERED IRON BARS AND MEASUREMENT OF YOUNG’S MODULUS BY VIBRATION
P.Kula et al. (Technical University, Tallin, Estonia.) Pokroky Pras. Metal., Vol36, No 1,1998,12-18. (In Czech.) The importance of powder particle morphology was discussed with regard to quantification by, for example, a form factor rather than a simple description. An approach to this by means of image analysis is described. Micrographs of powders were scanned and analysed for parameters such as aspect ratio, dispersion and geometrical factors. Significant differences between powders are identified.
B.Weiss et al. (Technical University of Vienna, Vienna, Austria.) Pokroky Pras. Metal., Vol 36, No 1, 1998, 19-27. (In Czech.) Samples of density graded Fe materials, layered in one direction, were prepared from powder. Young’s modulus was measured by standard and resonant methods. Effective modulus of samples with lower values in surface layers were evaluated by means of frequency of vibration parallel to the layer structure. The results are discussed.
Aluminium
PROPERTIES OF MECHANICALLY ALLOYED SPARK PLASMA SINTERED IRON-CHROMIUM ALLOY
SPARK PLASMA CONSOLIDATION OF MECHANICALLY ALLOYED AMORPHOUS Al ALLOY POWDER K.Ozaki et al. (National Industrial Research Inst. of Nagoya, Nagoya, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 12, 1997, 1126-1130. (In Japanese.) In an attempt to produce an amorphous bulk alloy Al-12at%Ti-lB%Si powders were mechanically alloyed to amorphize and spark plasma sintered to consolidate. The powder contained amorphous and nanocrystalline phases. The powder was coated with Sn by milling. The powders were sintered above the melting point of Sn but below the recrystallization range of the Al alloy powder. The structure, after sintering at 230°C for 20 minutes at a
N.Matsui et al. (Nagoya National Industrial Research Inst., Nagoya, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 12, 1997, 1121-1125. (In Japanese.) Powders corresponding to Fe-48at%Cr with 5wt%SiC were mechanically alloyed and spark plasma sintered. The materials contained the o-phase only in presence of Si and not in presence of C.
Titanium DIAMOND FILMS AS PROTECTIVE COATINGS ON TITANIUM ALLOYS l’.Grogler et al. (University of ErlangenNtirnberg, Erlangen, Germany.) Int. J. Refractory Metals Hard Mater., Vol 16, No 3,1998,217-222.
Sintering DISTRIBUTION OF ELECTRIC CURRFNT PATH AND TEMPERATURE IN SPARE SINTERING H.Watanabe et al. (Kagawa Industrial Technology Centre, Takamoto, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 10,1997,974-979. (In Japanese.) Spark sintering of Cu and AlzO, powders in graphite and insulating dies was investigated with reference to electric current paths. In the case of Cu in graphite dies almost all the current passed through the specimen. When the current was pulsed it also passed through the die and resulted in temperature variations in the sample. In the insulated die current passed through the graphite punches and the Cu and there was significant temperature fluctuation. With A&O, in graphite die and punches current passed through the graphite and there was considerable temperature variation in the samples.
Fundamentals PRODUCING FINE DROPLETS OF WATER BY TWIN FLUID ATOMIZATION D.A.Nguyen, M.J.Rhodes. (Monash University, Australia.) Powder Technol., Vol98, No 3, 1998,285-292. Atomization in two-fluid, air-water, atomizers, was investigated. Two atomizer nozzles are compared. One had internal mixing of the two fluids. In the 38
MPR May 1999
other, of novel design, the fluids were ejected through separate nozzles. Droplet sizes were measured as a function of the water:air ratio. Pressure drops were determined. SIZING TECHNIQUE FOR FINE POWDER DISPERSED IN AIR Y.Kousaka et al. (Osaka Prefecture University, Sakai, Japan.). Powder Technol., Vol 100, No 1,1998, 15-19. It is reported that a fine particle sizing technique had been developed in which a differential mobility analyser is combined with a condensation nucleus counter. A boiling method is used to break up aggregates into primary particles. The technique was applied to a range of powders including non-spherical and tightly agglomerated particles.
pressure of 375 MPa, contained amorphous and crystalline phases in an Sn rich matrix. CONSOLIDATION OF BALL MILLED ALUMINIUM ALLOY-SILICON CARBIDE COMPOSITE POWDERS M.S.El-Eskandarany et al. (Al-Ahzar University, Cairo, Egypt.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 10, 1997,1143-1147. (In English.) Al-lvol%(Ti, MO, Cul-BO%SiC powders were ball milled and the resulting nanocrystalline powders were consolidated by plasma activated sintering. Powders and compacts were characterized for structure, composition, hardness and density.
Iron and steel
APPLICATION OF IMAGE ANALYSIS TO EVALUATION OF POWDER PARTICLE MORPHOLOGY
VIBRATION OF SINTERED IRON BARS AND MEASUREMENT OF YOUNG’S MODULUS BY VIBRATION
P.Kula et al. (Technical University, Tallin, Estonia.) Pokroky Pras. Metal., Vol36, No 1,1998,12-18. (In Czech.) The importance of powder particle morphology was discussed with regard to quantification by, for example, a form factor rather than a simple description. An approach to this by means of image analysis is described. Micrographs of powders were scanned and analysed for parameters such as aspect ratio, dispersion and geometrical factors. Significant differences between powders are identified.
B.Weiss et al. (Technical University of Vienna, Vienna, Austria.) Pokroky Pras. Metal., Vol 36, No 1, 1998, 19-27. (In Czech.) Samples of density graded Fe materials, layered in one direction, were prepared from powder. Young’s modulus was measured by standard and resonant methods. Effective modulus of samples with lower values in surface layers were evaluated by means of frequency of vibration parallel to the layer structure. The results are discussed.
Aluminium
PROPERTIES OF MECHANICALLY ALLOYED SPARK PLASMA SINTERED IRON-CHROMIUM ALLOY
SPARK PLASMA CONSOLIDATION OF MECHANICALLY ALLOYED AMORPHOUS Al ALLOY POWDER K.Ozaki et al. (National Industrial Research Inst. of Nagoya, Nagoya, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 12, 1997, 1126-1130. (In Japanese.) In an attempt to produce an amorphous bulk alloy Al-12at%Ti-lB%Si powders were mechanically alloyed to amorphize and spark plasma sintered to consolidate. The powder contained amorphous and nanocrystalline phases. The powder was coated with Sn by milling. The powders were sintered above the melting point of Sn but below the recrystallization range of the Al alloy powder. The structure, after sintering at 230°C for 20 minutes at a
N.Matsui et al. (Nagoya National Industrial Research Inst., Nagoya, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 12, 1997, 1121-1125. (In Japanese.) Powders corresponding to Fe-48at%Cr with 5wt%SiC were mechanically alloyed and spark plasma sintered. The materials contained the o-phase only in presence of Si and not in presence of C.
Titanium DIAMOND FILMS AS PROTECTIVE COATINGS ON TITANIUM ALLOYS l’.Grogler et al. (University of ErlangenNtirnberg, Erlangen, Germany.) Int. J. Refractory Metals Hard Mater., Vol 16, No 3,1998,217-222.