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Synthesis of titanium carbide in aluminium base composites
Sintering MODELLING OF SUPERSOLIDUS LIQUID PHASE SINTERING - CAPILLARY FORCE
R.M. German et al. (Pennsylvania State University, Pennsylvania, USA) Metall. Muter. Truns A, Vol 26A, No 8, 1995, 2415-2422. Supersolidus liquid phase sintering of prealloyed powders is discussed with respect to partial melting and densification which involves increases in the amount of liquid and particle coalescence. A model for this is developed which takes variations of capillary force into account, This is reported to give better predictions than other models. Capillary force is shown to be affected by amount of liquid, wetting and particle shape. MODELLING
OF SUPERSOLIDUS
LIQUID PHASE SINTERING DENSIFICATION
-
R.M. German et al. (Pennsylvania State University, Pennsylvania, USA). Met&. Muter. Truns A, Vol 264 No 8, 1995, 2423-2430. A densiflcation model for supersolidus liquid phase sintering, which is analagous to viscous flow in rheology, is developed. The presence of a threshold value for the liquid film, and its effect on the onset of densification, is analyzed. Liquid film thickness is influenced by grain size and the amount of liquid, which are both affected by temperature. Two cases, a constant heating rate and isothermal conditions, are discussed. The model is shown to agree with a viscous flow induced densification mechanism. EFFECTOFCURRENTPULSE DISCHARGE ON SPECIFIC RESISTMTY OF COPPER AND IRON COMPACTS K. Matsugi et al. (Hiroshima University, Hiroshima, Japan). J. Japan Znst. Metals, Vol 59, No 7, 1995, 740-745. (In Japanese.) Spark sintering of Cu and Fe compacts was investigated. Relationships between number of pulses, and resistivity are established. Resistivity decreased with number of pulses, this being attributed to properties at particle/particle contact points in the form of dielectric breakdown of oxides. Metal/metal contacts are created after the breakdown. LIQUID PHASE SINTERING UNDER MICROGRAVITY CONDITIONS R.M. German et al. 50
MPR May 1996
(Pennsylvania State
University, Pennsylvania, USA). J. Metals, Vol 47, No 8, 1995, 46-48. It is reported that liquid phase sintering in microgravity allows a wider range of 1iquid:solid ratios than is the case in normal gravity, where the technique is restricted to high solid contents to ensure compact rigidity. Recent results on vacuum liquid phase sintering in microgravity are presented.
NON-LINEAR ELASTIC BEHAVIOUR OF COMPACTS WITH DIFFERENT POWDERS S. Kudela et al. Poroshkovuyu Metallurgiyu, No 11/12, 1994, 69-73. (In Russian.) Modelling of deformation of compacts made from powders of differing mechanical properties is described. The composite is considered as a three-phase body with a distribution of pores and rigid inclusions in an elastic matrix. Asymmetric character of properties is related to defect nucleation and decohesion at matrix/inclusion interfaces. OF POROSITY ON YOUNG’S
MODULUS
OF SINTERED
IRON
M. Kupkova et al. (Slovak Academy of Sciences, Kosice, Slovakia). Pokroky Prus kove
Metulurgie,
No
Aluminium SYNTHESIS OF TITANIUM CARBIDE IN ALUMINIUM BASE COMPOSITES
Fundamentals
EFFECT
of packs of spheres, with emphasis on anisotropy, is described. The structures are reduced to networks which show that anisotropy is present even in homogeneous packs. The influence of anisotropy on porous media properties, such as permeability, is highlighted.
l/2,
1995,
49-60.
(In Czech.) Predicted and measured values of as a function of Young’s modulus, porosity, of sintered Fe, are compared and good agreement is reported. CYCLIC COMPACTION OF POWDERS A. Sawicki, W. Swidzinski (IBW PAN, Gdansk-Oliwa, Poland). Powder Technol., Vol 85, No 2, 1995, 97-104. Studies of cyclic compaction of a range of metallic and non-metallic powders, using a Bishop oedometer are described. Discussion of the results centres on compaction and induced lateral stresses. It is shown that the various materials have characteristics in common. Equations linking compaction and lateral stresses are proposed. ANISOTROPY IN PORE STRUCTURE OF POROUS MEDIA C.A. Grdttoni, R.A Dawe (Imperial College, London, 1JK). Powider Technol., Vol 85, No 2, 1995, 143-151. Modelling of porous materials is discussed with regard to the property to be modelled, difficulties and the fact that anisotropy is often ignored. An examination
Z. Erlin et al. (Harbin Inst. of Technology, Harbin, China). PM Technol., Vol 13, No 3, 1995, 171-173. (In Chinese.) Preparation of AI-TIC composites, by in situ reactive synthesis of TIC was investigated with regard to Ti powder particle size and the microstructure. It is reported that AI-Tic composites can be prepared from elemental components. TIC particles were O.l-lum and were homogeneously distributed. Ti particle size influences reaction kinetics.
Iron and steel DIMENSIONAL SINTERING
CHANGES
DURING
OF IRON-BASED
POWDERS
J. Takata, N. Kawai (Kobe Steel Co Ltd, Takasogo, Japan). Powder Metall., Vol 38, No 3, 1995, 209-213. A study of dimensional changes in sintering of Fe-2%Cu-0.8%C-0.75XZn stearate is described. Abnormal expansion in the crFe range, after de-lubrication, is attributed to a carburizing reaction which affects sintering. Dimensional changes are discussed. EFFECT
OF INFILTRATION
ON
MECHANICAL
AND CORROSION
PROPERTIES
OF STAINLESS
STEELS
J.M. Torralba et al. (Polytechnic University of Madrid, Madrid, Spain). Znt. J. Powder Metull., Vol 31, No 4, 1995, 309-315. A study of the effects of infiltration by Cu or bronze, in varying amounts, on the mechanical properties and mineral acid corrosion resistance of 304L and 316L stainless steels is described. Bronze is reported to enhance resistance to hydrochloric and sulphuric acid. Resistance to nitric acid was reduced by Cu and bronze. FRACTURE
TOUGHNESS
AND
FATIGUE CRACK GROWTH IN COPPER INFILTRATED STEELS
E. Klar et al. (SCM Metal Products Ltd, North Carolina, USA). Znt. J. Powder Metull., Vol 31, No 4, 1995, 317-324.
R.M. German et al. (Pennsylvania State University, Pennsylvania, USA) Metall. Muter. Truns A, Vol 26A, No 8, 1995, 2415-2422. Supersolidus liquid phase sintering of prealloyed powders is discussed with respect to partial melting and densification which involves increases in the amount of liquid and particle coalescence. A model for this is developed which takes variations of capillary force into account, This is reported to give better predictions than other models. Capillary force is shown to be affected by amount of liquid, wetting and particle shape. MODELLING
OF SUPERSOLIDUS
LIQUID PHASE SINTERING DENSIFICATION
-
R.M. German et al. (Pennsylvania State University, Pennsylvania, USA). Met&. Muter. Truns A, Vol 264 No 8, 1995, 2423-2430. A densiflcation model for supersolidus liquid phase sintering, which is analagous to viscous flow in rheology, is developed. The presence of a threshold value for the liquid film, and its effect on the onset of densification, is analyzed. Liquid film thickness is influenced by grain size and the amount of liquid, which are both affected by temperature. Two cases, a constant heating rate and isothermal conditions, are discussed. The model is shown to agree with a viscous flow induced densification mechanism. EFFECTOFCURRENTPULSE DISCHARGE ON SPECIFIC RESISTMTY OF COPPER AND IRON COMPACTS K. Matsugi et al. (Hiroshima University, Hiroshima, Japan). J. Japan Znst. Metals, Vol 59, No 7, 1995, 740-745. (In Japanese.) Spark sintering of Cu and Fe compacts was investigated. Relationships between number of pulses, and resistivity are established. Resistivity decreased with number of pulses, this being attributed to properties at particle/particle contact points in the form of dielectric breakdown of oxides. Metal/metal contacts are created after the breakdown. LIQUID PHASE SINTERING UNDER MICROGRAVITY CONDITIONS R.M. German et al. 50
MPR May 1996
(Pennsylvania State
University, Pennsylvania, USA). J. Metals, Vol 47, No 8, 1995, 46-48. It is reported that liquid phase sintering in microgravity allows a wider range of 1iquid:solid ratios than is the case in normal gravity, where the technique is restricted to high solid contents to ensure compact rigidity. Recent results on vacuum liquid phase sintering in microgravity are presented.
NON-LINEAR ELASTIC BEHAVIOUR OF COMPACTS WITH DIFFERENT POWDERS S. Kudela et al. Poroshkovuyu Metallurgiyu, No 11/12, 1994, 69-73. (In Russian.) Modelling of deformation of compacts made from powders of differing mechanical properties is described. The composite is considered as a three-phase body with a distribution of pores and rigid inclusions in an elastic matrix. Asymmetric character of properties is related to defect nucleation and decohesion at matrix/inclusion interfaces. OF POROSITY ON YOUNG’S
MODULUS
OF SINTERED
IRON
M. Kupkova et al. (Slovak Academy of Sciences, Kosice, Slovakia). Pokroky Prus kove
Metulurgie,
No
Aluminium SYNTHESIS OF TITANIUM CARBIDE IN ALUMINIUM BASE COMPOSITES
Fundamentals
EFFECT
of packs of spheres, with emphasis on anisotropy, is described. The structures are reduced to networks which show that anisotropy is present even in homogeneous packs. The influence of anisotropy on porous media properties, such as permeability, is highlighted.
l/2,
1995,
49-60.
(In Czech.) Predicted and measured values of as a function of Young’s modulus, porosity, of sintered Fe, are compared and good agreement is reported. CYCLIC COMPACTION OF POWDERS A. Sawicki, W. Swidzinski (IBW PAN, Gdansk-Oliwa, Poland). Powder Technol., Vol 85, No 2, 1995, 97-104. Studies of cyclic compaction of a range of metallic and non-metallic powders, using a Bishop oedometer are described. Discussion of the results centres on compaction and induced lateral stresses. It is shown that the various materials have characteristics in common. Equations linking compaction and lateral stresses are proposed. ANISOTROPY IN PORE STRUCTURE OF POROUS MEDIA C.A. Grdttoni, R.A Dawe (Imperial College, London, 1JK). Powider Technol., Vol 85, No 2, 1995, 143-151. Modelling of porous materials is discussed with regard to the property to be modelled, difficulties and the fact that anisotropy is often ignored. An examination
Z. Erlin et al. (Harbin Inst. of Technology, Harbin, China). PM Technol., Vol 13, No 3, 1995, 171-173. (In Chinese.) Preparation of AI-TIC composites, by in situ reactive synthesis of TIC was investigated with regard to Ti powder particle size and the microstructure. It is reported that AI-Tic composites can be prepared from elemental components. TIC particles were O.l-lum and were homogeneously distributed. Ti particle size influences reaction kinetics.
Iron and steel DIMENSIONAL SINTERING
CHANGES
DURING
OF IRON-BASED
POWDERS
J. Takata, N. Kawai (Kobe Steel Co Ltd, Takasogo, Japan). Powder Metall., Vol 38, No 3, 1995, 209-213. A study of dimensional changes in sintering of Fe-2%Cu-0.8%C-0.75XZn stearate is described. Abnormal expansion in the crFe range, after de-lubrication, is attributed to a carburizing reaction which affects sintering. Dimensional changes are discussed. EFFECT
OF INFILTRATION
ON
MECHANICAL
AND CORROSION
PROPERTIES
OF STAINLESS
STEELS
J.M. Torralba et al. (Polytechnic University of Madrid, Madrid, Spain). Znt. J. Powder Metull., Vol 31, No 4, 1995, 309-315. A study of the effects of infiltration by Cu or bronze, in varying amounts, on the mechanical properties and mineral acid corrosion resistance of 304L and 316L stainless steels is described. Bronze is reported to enhance resistance to hydrochloric and sulphuric acid. Resistance to nitric acid was reduced by Cu and bronze. FRACTURE
TOUGHNESS
AND
FATIGUE CRACK GROWTH IN COPPER INFILTRATED STEELS
E. Klar et al. (SCM Metal Products Ltd, North Carolina, USA). Znt. J. Powder Metull., Vol 31, No 4, 1995, 317-324.