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Effect of particle size in copper oxide scale on properties of precipitated copper powder
Powder production
Fundamentals
C O N T R O L OF A P P A R E N T D E N S I T Y C O M P U T E R S I M U L A T I O N AND
MIXING O F U N I F O R M S I Z E D G ~ M A T E R I A L WITH ROTATIONAL OR ROCKING/ ROTATIONAL MOTIONS
ANALYSIS L.N.Smith, P.S.Midha. (University of the West of England, Bristol, UK.) Int. J. Powder Metall., Vol 34, No 3, 1998, 47-55. Use of c o m p u t e r s i m u l a t i o n and image analysis of particles, for control of metal powder quality and to predict packing density, is described. Models are developed for i r r e g u l a r s h a p e d particles. Visual a n a l y s i s is used to assess irregularity. Water a t o m i z e d powder is used as an example. Values for packing density can be determined with a facility for on-line monitoring. The s y s t e m is applied to commercial Fe powders. Predicted and experimental results are compared and a regression coefficient of 0.96 is obtained. The s t u d y is said to offer potential for intelligent control of powder production. E F F E C T O F P A R T I C L E SIZE IN C O P P E R OXIDE S C A L E O N PROPERTIES OF PRECIPITATED COPPER POWDER
J.Lezanski, A.Radon. (Akademia Gorniczo-Hutnicza, Krakow, Poland.) Rudy Metale, Vol 43, No 2, 1998, 87-90. (In Polish.) Stage 3 in the processing of Cu oxide scale into Cu powder is described. Effects of scale characteristics on morphology of the Cu powder and physical and technological properties of the precipitated powders are discussed.
Pressing A C O M P A C T I O N E Q U A T I O N A N D ITS U S E TO D E S C R I B E P O W D E R CONSOLIDATION
R.Panelli, F.A.Filho. (IPEN-CNEN/SP, C.University, Sao Paulo, Brazil.) Powder Metall., Vol 41, No 2, 1998, 131-133. A new compaction equation, which is easy to use and provides a description of consolidation and allows characterization of powder compaction by use of two p a r a m e t e r s , is presented. Based on published data, the results of linear regression analyses are reported to give correlation coefficients close to unity.
36 MPR March 1999
C.Wightman, F.J.Muzzio. (Rutgers University, Piscataway, USA.) Powder Technol., Vol 98, No 2, 1998, 113-124. The extent of mixing of uniformly sized granular materials, in drum mixers with rotational motion or rotational with rocking motion superimposed, was investigated as a function of time. The experiments were c h a r a c t e r i z e d - b y image analysis and by solidification of the contents of the drum. Pure rotational mixing was the slower of the two modes. MIXING OF SEGREGATING GRANULAR M A T E R I A L S W I T H ROTATIONAL OR ROCKING/ ROTATIONAL MOTIONS
C.Wightman, F.J.Muzzio. (Rutgers University, Piscataway, U S A . ) P o w d e r Technol., Vol 98, No 2, 1998, 125-134. Mixing of powders of differing sizes in cylindrical mills with pure rotation or rotation with rocking motions superimposed was investigated. Mixtures with complex p a t t e r n s were generated. Segregation of particle sizes was monitored. For short mixing times large particles segregated in zones. Longer times caused segregation of large particles at the ends of the mill. Some conditions gave near homogeneity.
Iron and steel EFFECT OF SINTERING TEMPERATURE ON PORE SHAPE MICROSTRUCTURE AND FATIGUE OF ALLOY STEEL
A.Piotrowski, G.Biallas. (University of Essen, Essen, Germany.) Powder Metall., Vol 41, No 2, 1998, 109-114. Effects of sintering temperature on pore morphology, microstructure and fatigue of 4%Ni-l.5%Cu-0.5%Mo steel, made from prealloyed powder, were investigated. Changes in electrical resistivity were used to monitor fatigue testing. Increased sintering t e m p e r a t u r e resulted in larger and more regularly shaped pores and more homogeneous distribution of alloy elements, with a small increase in endurance. Higher sintering t e m p e r a t u r e also resulted in
smaller changes in resistivity and lower plastic strain amplitude, lower homogeneous deformation rates and higher crack sensitivity. PRECIPITATION OF GRAPHITE DURING SINTERING IRON POWDER COMPACTS WITH BORON
Y.Nakano et al. (Kawasaki Steel Corp, Chiba, Japan.) J. Jpn Soc. Powder Powder Metall., Vol 44, No 9, 1997, 870875. (In Japanese.) Graphitization in Fe compacts containing graphite, B and S was investigated during sintering. Sintered struct u r e s contained ferrite and graphite. Solid residues, after dissolving the metallic Fe, were examined by X-ray diffraction. Free graphite is shown to have precipitated in pores in the sintered Fe.
Molybdenum N I T R I D I N G O F DILUTE
MOLYBDENUM-TITANIUM ALLOYS AT LOW T E M P E R A T U R E S O F 1000°C
M.Nagae et al. (Okayama University, Okayama, Japan.) Int. J. Refractory Metals Hard Mater., Vol 16, No 2, 1998, 127-132. Nitriding of Mo and Mo-0.5wt%Ti, in NH 3 at 1000°C, was investigated using microscopy, X-ray diffraction and hardness measurements. High surface Vickers hardness of about 1800 is reported. An outer layer of 7Mo2N and an inner layer of [3Mo2N were found. In Mo-Ti a further inner layer, with a hardness of 800, was detected. This is attributed to a fine dispersion of TiN particles. TENSILE PROPERTIES OF
MOLYBDENUM AIJ,OY PARALLEL A N D P E R P E N D I C U I J ~ TO EXTRUSION DIRECTION
J.Warren. (General Electric Medical Systems, Milwaukee, USA.) Int. J. Refractory Metals Hard Mater., Vol 16, No 2, 1998, 149-157. Tensile deformation and fracture of extruded Mo-0.5%Ti-0.8%Zr-0.25%C, precipitation hardening alloy, were investigated at 700°C, parallel and perpendicular to the extrusion direction. The dependence of tensile properties on orientation is considered with respect to effects on strain and fracture, the effects of plastic anisotropy and effects on ductility. There was only limited ductility perpendicular to the extrusion direction.
Fundamentals
C O N T R O L OF A P P A R E N T D E N S I T Y C O M P U T E R S I M U L A T I O N AND
MIXING O F U N I F O R M S I Z E D G ~ M A T E R I A L WITH ROTATIONAL OR ROCKING/ ROTATIONAL MOTIONS
ANALYSIS L.N.Smith, P.S.Midha. (University of the West of England, Bristol, UK.) Int. J. Powder Metall., Vol 34, No 3, 1998, 47-55. Use of c o m p u t e r s i m u l a t i o n and image analysis of particles, for control of metal powder quality and to predict packing density, is described. Models are developed for i r r e g u l a r s h a p e d particles. Visual a n a l y s i s is used to assess irregularity. Water a t o m i z e d powder is used as an example. Values for packing density can be determined with a facility for on-line monitoring. The s y s t e m is applied to commercial Fe powders. Predicted and experimental results are compared and a regression coefficient of 0.96 is obtained. The s t u d y is said to offer potential for intelligent control of powder production. E F F E C T O F P A R T I C L E SIZE IN C O P P E R OXIDE S C A L E O N PROPERTIES OF PRECIPITATED COPPER POWDER
J.Lezanski, A.Radon. (Akademia Gorniczo-Hutnicza, Krakow, Poland.) Rudy Metale, Vol 43, No 2, 1998, 87-90. (In Polish.) Stage 3 in the processing of Cu oxide scale into Cu powder is described. Effects of scale characteristics on morphology of the Cu powder and physical and technological properties of the precipitated powders are discussed.
Pressing A C O M P A C T I O N E Q U A T I O N A N D ITS U S E TO D E S C R I B E P O W D E R CONSOLIDATION
R.Panelli, F.A.Filho. (IPEN-CNEN/SP, C.University, Sao Paulo, Brazil.) Powder Metall., Vol 41, No 2, 1998, 131-133. A new compaction equation, which is easy to use and provides a description of consolidation and allows characterization of powder compaction by use of two p a r a m e t e r s , is presented. Based on published data, the results of linear regression analyses are reported to give correlation coefficients close to unity.
36 MPR March 1999
C.Wightman, F.J.Muzzio. (Rutgers University, Piscataway, USA.) Powder Technol., Vol 98, No 2, 1998, 113-124. The extent of mixing of uniformly sized granular materials, in drum mixers with rotational motion or rotational with rocking motion superimposed, was investigated as a function of time. The experiments were c h a r a c t e r i z e d - b y image analysis and by solidification of the contents of the drum. Pure rotational mixing was the slower of the two modes. MIXING OF SEGREGATING GRANULAR M A T E R I A L S W I T H ROTATIONAL OR ROCKING/ ROTATIONAL MOTIONS
C.Wightman, F.J.Muzzio. (Rutgers University, Piscataway, U S A . ) P o w d e r Technol., Vol 98, No 2, 1998, 125-134. Mixing of powders of differing sizes in cylindrical mills with pure rotation or rotation with rocking motions superimposed was investigated. Mixtures with complex p a t t e r n s were generated. Segregation of particle sizes was monitored. For short mixing times large particles segregated in zones. Longer times caused segregation of large particles at the ends of the mill. Some conditions gave near homogeneity.
Iron and steel EFFECT OF SINTERING TEMPERATURE ON PORE SHAPE MICROSTRUCTURE AND FATIGUE OF ALLOY STEEL
A.Piotrowski, G.Biallas. (University of Essen, Essen, Germany.) Powder Metall., Vol 41, No 2, 1998, 109-114. Effects of sintering temperature on pore morphology, microstructure and fatigue of 4%Ni-l.5%Cu-0.5%Mo steel, made from prealloyed powder, were investigated. Changes in electrical resistivity were used to monitor fatigue testing. Increased sintering t e m p e r a t u r e resulted in larger and more regularly shaped pores and more homogeneous distribution of alloy elements, with a small increase in endurance. Higher sintering t e m p e r a t u r e also resulted in
smaller changes in resistivity and lower plastic strain amplitude, lower homogeneous deformation rates and higher crack sensitivity. PRECIPITATION OF GRAPHITE DURING SINTERING IRON POWDER COMPACTS WITH BORON
Y.Nakano et al. (Kawasaki Steel Corp, Chiba, Japan.) J. Jpn Soc. Powder Powder Metall., Vol 44, No 9, 1997, 870875. (In Japanese.) Graphitization in Fe compacts containing graphite, B and S was investigated during sintering. Sintered struct u r e s contained ferrite and graphite. Solid residues, after dissolving the metallic Fe, were examined by X-ray diffraction. Free graphite is shown to have precipitated in pores in the sintered Fe.
Molybdenum N I T R I D I N G O F DILUTE
MOLYBDENUM-TITANIUM ALLOYS AT LOW T E M P E R A T U R E S O F 1000°C
M.Nagae et al. (Okayama University, Okayama, Japan.) Int. J. Refractory Metals Hard Mater., Vol 16, No 2, 1998, 127-132. Nitriding of Mo and Mo-0.5wt%Ti, in NH 3 at 1000°C, was investigated using microscopy, X-ray diffraction and hardness measurements. High surface Vickers hardness of about 1800 is reported. An outer layer of 7Mo2N and an inner layer of [3Mo2N were found. In Mo-Ti a further inner layer, with a hardness of 800, was detected. This is attributed to a fine dispersion of TiN particles. TENSILE PROPERTIES OF
MOLYBDENUM AIJ,OY PARALLEL A N D P E R P E N D I C U I J ~ TO EXTRUSION DIRECTION
J.Warren. (General Electric Medical Systems, Milwaukee, USA.) Int. J. Refractory Metals Hard Mater., Vol 16, No 2, 1998, 149-157. Tensile deformation and fracture of extruded Mo-0.5%Ti-0.8%Zr-0.25%C, precipitation hardening alloy, were investigated at 700°C, parallel and perpendicular to the extrusion direction. The dependence of tensile properties on orientation is considered with respect to effects on strain and fracture, the effects of plastic anisotropy and effects on ductility. There was only limited ductility perpendicular to the extrusion direction.