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High temperature mechanical properties of nickel aluminide with chromium or cerium
INDENTATION FRACTURE TOUGHNESS OF CEMENTED
CARBIDE
d. Hong (NGT Co, Rochester, New York, USA). J. Korean Inst. of Metals, Vol 32, No 11, 1994, 1396-1400. (In English.) An indentation fracture toughness investigation, using Rockwell hardness testing at three loads, of seven cemented carbide materials is described. The measured values are compared with short bar K,, fracture toughness values using published equations.
Metal injection moulding EFFECTS OF BINDER CONTENT AND PARTICLE SIZE ON GREEN STRENGTH OF WET POWDER POURED PARTS K. Vassen et al. (Forschungzentrum Jlich GmbH, Jlich, Germany.) Pr,lcder &fetallurgy, Vol 38, No 1, 1995, 55-58. The development of wet powder pouring, as an alternative to injection moulding because of the lower binder contents, 2-5vol’%, with shorter debinding times, is discussed. A study of the structure and properties of stainless steel made by WPP is described. A range of particle size distributions and binder contents, Z-8’%,, were investigated. Green strengths of 3-7 MPa are reported. A model linking green strength with binder content and particle size is proposed. INJECTION STEEL
transgranular cleavage, and quasi-cleavage the proportion of the latter increasing with Ni content.
boundary sliding. A stress exponent of 4 is given for higher strain rates showing a diffusion controlled mode
PREPARATION OF NICKEL ALUMINIDE BY SELF PROPAGATING HIGH TEMPERATURE SYNTHESIS
HIGH TEMPERATURE MECHANICAL PROPERTIES OF NICKEL ALUMINIDE WITH CHROMIUM OR CERIUM
.J.C Jung et al. (Chungnam National University, Daejeon, Korea). J. Korean Inst. of Metals, Vol 32, No 9, 1994, 1084-1091. (In Korean.) Studies of the formation of NiAl by SHS are described. The synthesis is reported to be affected by mole ratio, compaction pressure and particle size. Combustion temperature is reduced by increased compaction pressure. Densilication was enhanced by applied pressure.
K. Ono et al. (University of California, Los Angeles, California, USA). J. Japan SW. Powder und Pou1de-r Metallurgy, Vol 4 1, No 5, 1994, 524-529. (In English.) Attempts to prepare NiAls reinforced with Al,O,, libre, which is compatible with the aluminide, are described. Effects of additions of Cr, Ce or B additions on tensile properties were also investigated.
STUDIES OF DUCTILITY IMPROVEMENT IN BRITTLE INTERMETALLIC MATERIALS S. Hanada (Tohoku University, Sendai, Japan). J. Japun Sac. Powder and Powder Metallurgy, Vol41, xo 5, 1994, 483488. (In Japanese.) Ductility of brittle intermetallics is discussed with regard to grain boundary chemistry, phase stability, environmental embrittlement, Feierl’s stress at ambiment temperatures and means of increasing ductility. It is reported that NbaAl has a high strength at high temperature and that a line dispersion of a Nb solid solution enhances ductility.
MOULDING OF STAINLESS
G. Veltl et al. (Fraunhofer Inst. for Applied Materials Research, Bremen, Germany). Mater. and Manuf Processes, Vol 10, No 3, 1995, 425-238. Injection moulding of 316L stainless steel from gas and/or water atomized powders was investigated. Tensile specimens were moulded with a thermoplastic binder and effects of process methods on ‘KC in the product were determined. Effects of powder morphology on debinding and sintering are discussed. Shrinkage was correlated with powder characteristics.
lntermetallic compound materials
EFFECT OF PROCESS CONDITIONS ON DISTORTION OF INJECTION MOULDED TITANIUM ALUMINIDE Y. Osafune et al. (Muroran Inst. of Technology, Morurdn, Japan). J. Japun Sot. Pmder and Powder Metallurgy, Vol 41, No 5, 1994, 506-509. (In Japanese.) Distortion during debinding and sintering was investigated as functions of process conditions. Debinding was by solvent extraction and thermal decomposition/evaporation. Vacuum sintering gave higher density than sintering in air or Ar. It is considered important to prevent oxide formation on the compacts, Embedding compacts in alumina powder is shown to limit oxide formation and distortion.
THE ROLE OF NICKEL IN FORMATION OF IRON ALUMINIDE
COMPRESSIVE DEFORMATION OF PM TITANIUM ALUMINIDE AT HIGH TEMPERATURES
X. Wang, J.V. Wood (University of Nottingham, Nottingham, UK). Powder Metallurgy, Vol 38, No 1, 1994, 59-65. The effect of Ni on structure and properties of Fe&l was investigated on samples made from elemental powders. Ni is reported to enhance densification to near full density. Hardness, tensile strength and ductility increase with ‘%,Ni.Fracture mode in tension is shown to be a mixture of
K. Higashi et al. (University of Osaka prefecture, Sakai, Osaka, Japan). J. Japan Sot. Powder und Powder Metallurgy, Vol 41, No 5, 1994, 510-513. (In English.) Compressive deformation of sintered TiAl, with a grain size of about 6 pm was investigated at strain rates of 4x10~” to lO~“sec~’ and 1100°C. At lower strain rates the stress exponent is reported to be 2 indicating that deformation is by grain
PREPARATION OF TITANIUMALUMINIUM POWDERS BY MECHANICAL ALLOYING AND FABRICATION
K. Koyobashi et al. (National Research Inst., Nagoya, Japan).
Industrial J. Japan Sot. Powder and Powder Metallurgy, Vol 41, No 5, 1994, 536-539. (In Japanese.) A study of the mechanical alloying of elemental Ti-&4l powder mixtures in Ar is described. The powders are shown to be agglomerated dispersions of Ti and Al. Ti34wt!%l was hot pressed at 609800°C and 600 MPa. Densities up to 85% were attained and aluminude formed.
Mechanical alloying ENERGY TRANSFER AND AMORPHIZATION OF NICRELTITANIUM IN MECHANICAL ALLOYING W.C. Huo et al. (Harbin Inst. of Technology, China). Ma,terials Science Progress, Vol 7, No 6, 1993, 491-496. (In Chinese.) The effects of rotation spreed and number of balls on attrition amorphization of Ni-SOat%Ti elemental powders were investigated. A mode1 for calculation of energy transfer is introduced. Relationships between phase transformations and process parameters are discussed. Excessive plastic deformation may cause synthesis of i ntermetallic compounds.
PM”TEC’95: The abstracts which follow are from papers which were presented at the International Conference on Powder Metallurgy and Particulate Materials which was held in Seattle, USA, from 14th to 17th May 1995.
Hot isostatic press processing and density HOT ISOSTATIC PRESSING OF COMPLEX SHAPED PARTS
R.A. Khaykin et al. (Interlink The role of HIP in the
Corp, USA). range of PM
MPR February
1996
41
CARBIDE
d. Hong (NGT Co, Rochester, New York, USA). J. Korean Inst. of Metals, Vol 32, No 11, 1994, 1396-1400. (In English.) An indentation fracture toughness investigation, using Rockwell hardness testing at three loads, of seven cemented carbide materials is described. The measured values are compared with short bar K,, fracture toughness values using published equations.
Metal injection moulding EFFECTS OF BINDER CONTENT AND PARTICLE SIZE ON GREEN STRENGTH OF WET POWDER POURED PARTS K. Vassen et al. (Forschungzentrum Jlich GmbH, Jlich, Germany.) Pr,lcder &fetallurgy, Vol 38, No 1, 1995, 55-58. The development of wet powder pouring, as an alternative to injection moulding because of the lower binder contents, 2-5vol’%, with shorter debinding times, is discussed. A study of the structure and properties of stainless steel made by WPP is described. A range of particle size distributions and binder contents, Z-8’%,, were investigated. Green strengths of 3-7 MPa are reported. A model linking green strength with binder content and particle size is proposed. INJECTION STEEL
transgranular cleavage, and quasi-cleavage the proportion of the latter increasing with Ni content.
boundary sliding. A stress exponent of 4 is given for higher strain rates showing a diffusion controlled mode
PREPARATION OF NICKEL ALUMINIDE BY SELF PROPAGATING HIGH TEMPERATURE SYNTHESIS
HIGH TEMPERATURE MECHANICAL PROPERTIES OF NICKEL ALUMINIDE WITH CHROMIUM OR CERIUM
.J.C Jung et al. (Chungnam National University, Daejeon, Korea). J. Korean Inst. of Metals, Vol 32, No 9, 1994, 1084-1091. (In Korean.) Studies of the formation of NiAl by SHS are described. The synthesis is reported to be affected by mole ratio, compaction pressure and particle size. Combustion temperature is reduced by increased compaction pressure. Densilication was enhanced by applied pressure.
K. Ono et al. (University of California, Los Angeles, California, USA). J. Japan SW. Powder und Pou1de-r Metallurgy, Vol 4 1, No 5, 1994, 524-529. (In English.) Attempts to prepare NiAls reinforced with Al,O,, libre, which is compatible with the aluminide, are described. Effects of additions of Cr, Ce or B additions on tensile properties were also investigated.
STUDIES OF DUCTILITY IMPROVEMENT IN BRITTLE INTERMETALLIC MATERIALS S. Hanada (Tohoku University, Sendai, Japan). J. Japun Sac. Powder and Powder Metallurgy, Vol41, xo 5, 1994, 483488. (In Japanese.) Ductility of brittle intermetallics is discussed with regard to grain boundary chemistry, phase stability, environmental embrittlement, Feierl’s stress at ambiment temperatures and means of increasing ductility. It is reported that NbaAl has a high strength at high temperature and that a line dispersion of a Nb solid solution enhances ductility.
MOULDING OF STAINLESS
G. Veltl et al. (Fraunhofer Inst. for Applied Materials Research, Bremen, Germany). Mater. and Manuf Processes, Vol 10, No 3, 1995, 425-238. Injection moulding of 316L stainless steel from gas and/or water atomized powders was investigated. Tensile specimens were moulded with a thermoplastic binder and effects of process methods on ‘KC in the product were determined. Effects of powder morphology on debinding and sintering are discussed. Shrinkage was correlated with powder characteristics.
lntermetallic compound materials
EFFECT OF PROCESS CONDITIONS ON DISTORTION OF INJECTION MOULDED TITANIUM ALUMINIDE Y. Osafune et al. (Muroran Inst. of Technology, Morurdn, Japan). J. Japun Sot. Pmder and Powder Metallurgy, Vol 41, No 5, 1994, 506-509. (In Japanese.) Distortion during debinding and sintering was investigated as functions of process conditions. Debinding was by solvent extraction and thermal decomposition/evaporation. Vacuum sintering gave higher density than sintering in air or Ar. It is considered important to prevent oxide formation on the compacts, Embedding compacts in alumina powder is shown to limit oxide formation and distortion.
THE ROLE OF NICKEL IN FORMATION OF IRON ALUMINIDE
COMPRESSIVE DEFORMATION OF PM TITANIUM ALUMINIDE AT HIGH TEMPERATURES
X. Wang, J.V. Wood (University of Nottingham, Nottingham, UK). Powder Metallurgy, Vol 38, No 1, 1994, 59-65. The effect of Ni on structure and properties of Fe&l was investigated on samples made from elemental powders. Ni is reported to enhance densification to near full density. Hardness, tensile strength and ductility increase with ‘%,Ni.Fracture mode in tension is shown to be a mixture of
K. Higashi et al. (University of Osaka prefecture, Sakai, Osaka, Japan). J. Japan Sot. Powder und Powder Metallurgy, Vol 41, No 5, 1994, 510-513. (In English.) Compressive deformation of sintered TiAl, with a grain size of about 6 pm was investigated at strain rates of 4x10~” to lO~“sec~’ and 1100°C. At lower strain rates the stress exponent is reported to be 2 indicating that deformation is by grain
PREPARATION OF TITANIUMALUMINIUM POWDERS BY MECHANICAL ALLOYING AND FABRICATION
K. Koyobashi et al. (National Research Inst., Nagoya, Japan).
Industrial J. Japan Sot. Powder and Powder Metallurgy, Vol 41, No 5, 1994, 536-539. (In Japanese.) A study of the mechanical alloying of elemental Ti-&4l powder mixtures in Ar is described. The powders are shown to be agglomerated dispersions of Ti and Al. Ti34wt!%l was hot pressed at 609800°C and 600 MPa. Densities up to 85% were attained and aluminude formed.
Mechanical alloying ENERGY TRANSFER AND AMORPHIZATION OF NICRELTITANIUM IN MECHANICAL ALLOYING W.C. Huo et al. (Harbin Inst. of Technology, China). Ma,terials Science Progress, Vol 7, No 6, 1993, 491-496. (In Chinese.) The effects of rotation spreed and number of balls on attrition amorphization of Ni-SOat%Ti elemental powders were investigated. A mode1 for calculation of energy transfer is introduced. Relationships between phase transformations and process parameters are discussed. Excessive plastic deformation may cause synthesis of i ntermetallic compounds.
PM”TEC’95: The abstracts which follow are from papers which were presented at the International Conference on Powder Metallurgy and Particulate Materials which was held in Seattle, USA, from 14th to 17th May 1995.
Hot isostatic press processing and density HOT ISOSTATIC PRESSING OF COMPLEX SHAPED PARTS
R.A. Khaykin et al. (Interlink The role of HIP in the
Corp, USA). range of PM
MPR February
1996
41