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Development of guide roller material for steel wire-rod mill
An investigation of the effects of Sic, thin and thick whiskers and rod-like particles on the mechanical properties of A&O,-SiC composites is described. Fracture strength and toughness were measured in relation to the thickness of the reinforcements. Critical flaw size is calculated.
Electrical materials
and magnetic
MAGNETIC PROPERTIES OF SINTERED IRON-CHROMIUM ALLOY IN ALTERNATING FIELD T.Kato et al. (Daido Inst. of Technology, Nagoya. Japan.) J. elpn Sot. Powder Powder Metall., Vol 43, No 2, 1996, 226229. (In Japanese.) The magnetic properties, in an alternating field, of sintered Fe-12.5%Cr alloys with and without 0.1 to 0.2% of mixed SiO,,, CaO and A&O, were investigated. Hysteresis curves are compared with results for cast materials. The magnetic properties, in alternating fields, are reported to be improved by the added oxides. MAGNETIC PROPERTIES OF NEODYMIUM-IRON-BORON SINTERED FROM GRANULATED POWDERS O.Yamashita, YKishimoto. (Sumitomo Special Metals Co Ltd. Osaka, Japan.) J. Jpn Sot. Powder Poroder Metall., Vol 43, No 2, 1996, 249-255. (In Japanese.) The use of a spray drying process to granulate Nd-Fe-B magnetic powders, with PVA, glycerine and water as the binder, is reported. After pressing in a magnetic field, compacts were debound in H at 400°C. which removed 90% of the binder C. Magnetic properties are described.
Hard materials steels
and tool
DEVELOPMENT OF GUIDE ROLLER MATERIAL FOR STEEL WIRE-ROD MILL M.V.Deshpande et ai. (Sandvik Asia Ltd, Pune, India.) Inl. J. Refractory Metals Hard Mater., Vol 15, No 1-3, 1997,151.155. Development of a cermet with about 50%TiC in a Fe-Co-xi-Mo matrix is reported. The material is shown to have a good combination of hardness, toughness and low density, and can be used as guides in high speed Isteel wire-rod rolling mills. Processing, properties and performance are discussed. TOUGHER CEMENTED CARBIDE MATERIAL WITH IRON-RICH BINDER FOR STEEL TURNING
M.V.Deshpande et al. (Sandvik Asia Ltd, Pune, India.) ht. J. Refractory Metals Hard Muter., Vol 15, No l-3, 1997, 157-162. A cemented carbide material with WC in an Fe-based matrix is described. The alloy is shown to be intermediate between high speed steels and conventional cemented carbides. Mechanical properties were measured. It is reported that higher cutting speeds are possible than with conventional high speed steels. PREPARATION OF FINE MIXED TUNGSTEN/VANADIUM CARBIDE POWDERS L.Cornish et al. (University of the Witwatersrand, Johannesburg, South Africa.) Int. J. Refractory Metals Hard Mater., Vol 15, No 1-3, 1997, 163-168. The object of the work described was to prepare WC-V&, and WC-V,C, powders, with grain sizes of 1 to 2 pm for use in making WC-VC-Co cemented carbides. WC-V,C, was made either from mixed carbides or from V,O,. WC and carbon black. WC-V,C,, could not be made.
Intermetallic
materials
FABRICATION AND MICROSTRUCTURE OF NIOBIUM ALUMINIDE N.Nomura et al. (Tohoku University, Sendai, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 43, No 2, 1996, 256. 261. (In Japanese.) It is reported that Nb,Al powder had been produced by rotating electrode atomization. The powder was rapidly solidified with a dendritic body-centred cubic structure which was stable to high temperatures. The powder was hot pressed and the structure contained Nb,Al and a Nb rich solid solution. The methods are shown to enable production of near net-shape parts. FABRICATION OF ALUMINA REINFORCED NICKEL ALUMINIDE BY NOVEL IN SITU PROCESS SNourbakhsh et al. (Polytechnic University, Brooklyn, New York, USA.) Metall. Mater. Trans. A, Vol 28A, No 4, 1997, 1069-1077. Production of a N&Al-Al,O, composite is described. The material was made by pressure casting the intermetallic, with 0.34at%Zr, to incorporate a low volume fraction of Al,O, fibres. Some A&O, was reduced by Zr to form ZrO, on the surface of the fibres. Annealing in air for ten days at 1100°C caused formation of
a network of A&O, round the fibres. The matrix close to ‘the fibres comprised NiaAl and disordered NiAl. The final composite had increased strength. MICROSTRUCTURE AND MECHANICAL BEHAVIOUR OF NICKEL ALUMINIDETITANIUM CARBIDE COMPOSITE Z.P.Xing et al. (Inst. of Aeronautical Materials, Beijing, China.) Metall. Mater. Trans. A, Vol 28A, No 4, 1997. 1079-1087. Structure, interfaces and mechanical properties of NiAl-TiC composites. formed in situ from elemental Ni, Al, Ti and C powders by hot pressing and exothermic synthesis and HIP or annealing, were investigated. TiC particles were polygonal and facetted. Interfaces between TiC and NiAl were smooth and free from interfacial phases. Two orientation relationships between TiC and NiAl were found. The composite had properties superior to those of unrrinforced NiAl. PREPARATION ALUMINIDE
OF TITANIUM
Y.P.Smirnov et al. Poroskovaya Metall.. No 9/10, 1996, 5-8. (In Russian.) Fabrication of TiAl and TiAl alloyed with Cr or Mn was investigated for powders which had not been milled. Mn and Cr are reported to increase the strength and hardness of the TiAl by formation of a solid solution. Processing of TiAl powders with A&O, coatings was also studied.
Mechanical
alloying
MICROSTRUCTURALDEVELOPMENT IN MECHANICALLY ALLOYED AND HEAT TREATED NICKEL ALUMINIDE P.Grahle, E.Artz. (Max-Planck Inst., Stuttgart, Germany.) Acta Mater., Vol 45, No 1, 1997, 201-21 I. It is reported that to increase the creep strength, NiAl had been mechanically alloyed with an oxide dispersoid and heat treated to recrystallize. Powders and consolidated materials were characterized. It is shown that coarsening of the dispersoids can be inhibited by allowing abnormal grain growth. It is demonstrated that the conflicting demands of small dispersoids and large grains can be controlled in processing. MECHANICAL ALLOYING OF TITANIUM-ALUMINIUM-NIOBIUM D.Ernst et al. (University of Siegen. Germany.) Metall., Vol 50, No 9, 1996. 575579.
MPR January 1998 37
Electrical materials
and magnetic
MAGNETIC PROPERTIES OF SINTERED IRON-CHROMIUM ALLOY IN ALTERNATING FIELD T.Kato et al. (Daido Inst. of Technology, Nagoya. Japan.) J. elpn Sot. Powder Powder Metall., Vol 43, No 2, 1996, 226229. (In Japanese.) The magnetic properties, in an alternating field, of sintered Fe-12.5%Cr alloys with and without 0.1 to 0.2% of mixed SiO,,, CaO and A&O, were investigated. Hysteresis curves are compared with results for cast materials. The magnetic properties, in alternating fields, are reported to be improved by the added oxides. MAGNETIC PROPERTIES OF NEODYMIUM-IRON-BORON SINTERED FROM GRANULATED POWDERS O.Yamashita, YKishimoto. (Sumitomo Special Metals Co Ltd. Osaka, Japan.) J. Jpn Sot. Powder Poroder Metall., Vol 43, No 2, 1996, 249-255. (In Japanese.) The use of a spray drying process to granulate Nd-Fe-B magnetic powders, with PVA, glycerine and water as the binder, is reported. After pressing in a magnetic field, compacts were debound in H at 400°C. which removed 90% of the binder C. Magnetic properties are described.
Hard materials steels
and tool
DEVELOPMENT OF GUIDE ROLLER MATERIAL FOR STEEL WIRE-ROD MILL M.V.Deshpande et ai. (Sandvik Asia Ltd, Pune, India.) Inl. J. Refractory Metals Hard Mater., Vol 15, No 1-3, 1997,151.155. Development of a cermet with about 50%TiC in a Fe-Co-xi-Mo matrix is reported. The material is shown to have a good combination of hardness, toughness and low density, and can be used as guides in high speed Isteel wire-rod rolling mills. Processing, properties and performance are discussed. TOUGHER CEMENTED CARBIDE MATERIAL WITH IRON-RICH BINDER FOR STEEL TURNING
M.V.Deshpande et al. (Sandvik Asia Ltd, Pune, India.) ht. J. Refractory Metals Hard Muter., Vol 15, No l-3, 1997, 157-162. A cemented carbide material with WC in an Fe-based matrix is described. The alloy is shown to be intermediate between high speed steels and conventional cemented carbides. Mechanical properties were measured. It is reported that higher cutting speeds are possible than with conventional high speed steels. PREPARATION OF FINE MIXED TUNGSTEN/VANADIUM CARBIDE POWDERS L.Cornish et al. (University of the Witwatersrand, Johannesburg, South Africa.) Int. J. Refractory Metals Hard Mater., Vol 15, No 1-3, 1997, 163-168. The object of the work described was to prepare WC-V&, and WC-V,C, powders, with grain sizes of 1 to 2 pm for use in making WC-VC-Co cemented carbides. WC-V,C, was made either from mixed carbides or from V,O,. WC and carbon black. WC-V,C,, could not be made.
Intermetallic
materials
FABRICATION AND MICROSTRUCTURE OF NIOBIUM ALUMINIDE N.Nomura et al. (Tohoku University, Sendai, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 43, No 2, 1996, 256. 261. (In Japanese.) It is reported that Nb,Al powder had been produced by rotating electrode atomization. The powder was rapidly solidified with a dendritic body-centred cubic structure which was stable to high temperatures. The powder was hot pressed and the structure contained Nb,Al and a Nb rich solid solution. The methods are shown to enable production of near net-shape parts. FABRICATION OF ALUMINA REINFORCED NICKEL ALUMINIDE BY NOVEL IN SITU PROCESS SNourbakhsh et al. (Polytechnic University, Brooklyn, New York, USA.) Metall. Mater. Trans. A, Vol 28A, No 4, 1997, 1069-1077. Production of a N&Al-Al,O, composite is described. The material was made by pressure casting the intermetallic, with 0.34at%Zr, to incorporate a low volume fraction of Al,O, fibres. Some A&O, was reduced by Zr to form ZrO, on the surface of the fibres. Annealing in air for ten days at 1100°C caused formation of
a network of A&O, round the fibres. The matrix close to ‘the fibres comprised NiaAl and disordered NiAl. The final composite had increased strength. MICROSTRUCTURE AND MECHANICAL BEHAVIOUR OF NICKEL ALUMINIDETITANIUM CARBIDE COMPOSITE Z.P.Xing et al. (Inst. of Aeronautical Materials, Beijing, China.) Metall. Mater. Trans. A, Vol 28A, No 4, 1997. 1079-1087. Structure, interfaces and mechanical properties of NiAl-TiC composites. formed in situ from elemental Ni, Al, Ti and C powders by hot pressing and exothermic synthesis and HIP or annealing, were investigated. TiC particles were polygonal and facetted. Interfaces between TiC and NiAl were smooth and free from interfacial phases. Two orientation relationships between TiC and NiAl were found. The composite had properties superior to those of unrrinforced NiAl. PREPARATION ALUMINIDE
OF TITANIUM
Y.P.Smirnov et al. Poroskovaya Metall.. No 9/10, 1996, 5-8. (In Russian.) Fabrication of TiAl and TiAl alloyed with Cr or Mn was investigated for powders which had not been milled. Mn and Cr are reported to increase the strength and hardness of the TiAl by formation of a solid solution. Processing of TiAl powders with A&O, coatings was also studied.
Mechanical
alloying
MICROSTRUCTURALDEVELOPMENT IN MECHANICALLY ALLOYED AND HEAT TREATED NICKEL ALUMINIDE P.Grahle, E.Artz. (Max-Planck Inst., Stuttgart, Germany.) Acta Mater., Vol 45, No 1, 1997, 201-21 I. It is reported that to increase the creep strength, NiAl had been mechanically alloyed with an oxide dispersoid and heat treated to recrystallize. Powders and consolidated materials were characterized. It is shown that coarsening of the dispersoids can be inhibited by allowing abnormal grain growth. It is demonstrated that the conflicting demands of small dispersoids and large grains can be controlled in processing. MECHANICAL ALLOYING OF TITANIUM-ALUMINIUM-NIOBIUM D.Ernst et al. (University of Siegen. Germany.) Metall., Vol 50, No 9, 1996. 575579.
MPR January 1998 37