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Porous sleeve bearings — air and oil permeability
Japan.) J. ~~iz~~wn Srrc. 64noder Powder Metall., Vol 42, No 2. 1995, 156.160 and 161-166. (ln Japanese.) Studies of the effects of process conditions on structures and electro/ magnetic properties of mechanicallyground SmFe-N are described. Attempts were made to reduce grain size below magnet.ic domain Si’ix! of 300 nm. Grinding, heat treatment and nitriding were studied.
IIiGH
SPEED E BY PM
STEEL
TREATMENT OF WITH MANGANESE
F.A.Filho et al. Metui. A!!-ater. IPBM., voi 51, No 441, 1995, 426-431. (In Portugese.) Optimum proiluct.ion data for M2 HSS and a. special HSS with higher carbon are presented. Steels were compacted at X00 MPa and sirrtrwd at 1220 to 1260°C and 1180 to 126O’C respectively. Properties are related to heat treatment conditions and
applications.
HIGH
SPEED SULPHIDE
J.D.Bolton, AJ. Gant (University of Bradford, Bradford, UK.)Powder Metall.,Vol 39, No 1, 1996, 27-35. Studies of M2/3 HSS sintered to full density with TIC, NbC or MnS singly, TiC and MnS or NbC and MnS in combination are described. Hardness was reduced in any sample containing MnS. In TiC composites MC carbides are replaced by M& with a small drop in hardness, Powder mixtures with NbC needed milling to disperse particle agglomerates. NbC enhanced mechanical properties in comparison with conventional M2/3 HSS. ~C~I~~NG COMPOSITES
AKawasaki 81 ut. (Tohoku University, Sendai, Japan.) Ma?:. de ~%!&ull., Vol 93; No 2, 1996, 185.1Q6. (IT. French.) Functionally gradient materials, with one-, or more, -dimensional composition gradients are critically reviewed with reference to minimizing the thermal stresses which oe~.ur in bi-material devices. The use of PM in manufacture is discussed. It is noted t,hat PM allows attainment of properties that cannot be achieved in any other way. The importance of process control is emphasized. A number of techniques, including centrifugal PM are considered. Attention is dram to the fact that test proseedures may need modification fo: Pt:nctinnallygradient materials.
DIES
STalacchia et al. (University of Navarra, San Sebastian, Spain.) Rev. de Metall., Vol 32, No 1, 1996, 18-24. Studies of M2, M2/3 and T42 modified with C and V are described. Cut-off dies were sintered in a N-H-CH4 atmosphere and a range of heat treatments were applied. A Vicker’s hardness of 1100 was attained in modified T42. Sintering shrinkages were also measured pi
Mechanical alloying, in air, of Fe-Zr powders and effects on structure and electrical properties were investigated with regard to use of acetone or ethanol additives during milling. Witlmut additives coercive force W;LS increased, Acetone init,ially increased coercive force which then declined with milling time increase. The additives enhanced formation of FeZrO,, compositrs from mixed Fe-Zr powders.
STEEL CUT-OFF TECHNIQUES
OF METAL MATRIX WITH DIAMOND
TOOLS
HSOberoi (Western Washington University USA.) Cutting Tool Neuis, No 2, 1996, B-10. Properties, structures and applications of metal matrix composites are discussed -with reference to difficulties in machining composites with very hard reinforcements. It is reported that the cutting behaviour of a range of diamond cutting tool materials, including polycrystalline diamond and diamond coated materials, had been compared with reference to tool life and wear characteristics.
etallic
T.Masumoto et al. (Tohoku University, Sendai, Japan.) J. Japan Sot. Powder Powder Metall., Vol 42, No 2, 1995, 175. 179. (In Japanese.) It is suggested that a pulse discharge resistance technique can be used to consolidate NiTi and TiAl under pseudoisostatic pressure to near net shape and near full density. The method used spherical graphite granules as the pressure transmitting medium.
KShibue
SINTERPNG
(Sumitomo
OF
Light
LIGHT
Metal
POWER ~~UR~~ENTS MECHANICAL MILLING INVESTIGATE ENERGY
Indus-
DUBING SFER
A.Iasonna, MMagini (ENEA-INN-NUMA, C.R.Casaccia, Rome, Italy.)Acla Mnter., Vol 44, No 3, 1996, 1109-1117. A model evaluation of energy transfer and power consumption during milling is presented with measurements of power consumption. Good agreement between predicted and experimental values is reported. Relationships between rotation speed, packing of the mill, energy transfer and power consumption are established. Practical consequences are illustrated.
POROUS SLEEVE OIL PERMEABILI
KMCielicki, KKrzeminski (University of Technology, Warsaw, Poland.) Int. J. Pow*der Metall., Vol 32, No 1, 1996, 175-183. Results of measurements of air and oil permeability for porous sleeve bearing materials are presented. Flow characteristics are simpler for air than oil. Pressure/flow rate is non-linear for air. Relationships between calculated and measured results are given. CONTACT INTELLIGENT BREAKER
materials
RMETALLIC
‘FIVE ~NT~~~~~~LICS
tries, Japan.) J. Japan Inst. fiigkt Metals, Vol44, No 11, X994, 614-621. (In Japanese.) Synthesis, structure and properties of aluminides are discussed and a model of reactive sintering is proposed. Pore reduction by HIP of TiAl and TiAlMn is considered. A range of fabrication methods is outlined. The importance of heat treatment is emphasized. It is shown that reactively sintered TiAlMn with additions of TiBz is better than a cast alloy.
MATERIALS FRAME
FOR CIRCIUT
Z.Mingjiang et al. (Electrical Equipment Scientific Research Inst., Guilin, China.) PM Technol., Vol 14, No 1, 1996, 30-36. (In Chinese.) Studies of W-Ag and Ag-Ni-graphite materials, with a presintered W skeleton, for heavy duty circuit breakers are reported. Arc burning and erosion testing were used. Paired contacts of W-5O%Ag/Ag-25%Ni-2!XC satisfy the requirements for most applications.
follow
are
of papers
which
were
IIiGH
SPEED E BY PM
STEEL
TREATMENT OF WITH MANGANESE
F.A.Filho et al. Metui. A!!-ater. IPBM., voi 51, No 441, 1995, 426-431. (In Portugese.) Optimum proiluct.ion data for M2 HSS and a. special HSS with higher carbon are presented. Steels were compacted at X00 MPa and sirrtrwd at 1220 to 1260°C and 1180 to 126O’C respectively. Properties are related to heat treatment conditions and
applications.
HIGH
SPEED SULPHIDE
J.D.Bolton, AJ. Gant (University of Bradford, Bradford, UK.)Powder Metall.,Vol 39, No 1, 1996, 27-35. Studies of M2/3 HSS sintered to full density with TIC, NbC or MnS singly, TiC and MnS or NbC and MnS in combination are described. Hardness was reduced in any sample containing MnS. In TiC composites MC carbides are replaced by M& with a small drop in hardness, Powder mixtures with NbC needed milling to disperse particle agglomerates. NbC enhanced mechanical properties in comparison with conventional M2/3 HSS. ~C~I~~NG COMPOSITES
AKawasaki 81 ut. (Tohoku University, Sendai, Japan.) Ma?:. de ~%!&ull., Vol 93; No 2, 1996, 185.1Q6. (IT. French.) Functionally gradient materials, with one-, or more, -dimensional composition gradients are critically reviewed with reference to minimizing the thermal stresses which oe~.ur in bi-material devices. The use of PM in manufacture is discussed. It is noted t,hat PM allows attainment of properties that cannot be achieved in any other way. The importance of process control is emphasized. A number of techniques, including centrifugal PM are considered. Attention is dram to the fact that test proseedures may need modification fo: Pt:nctinnallygradient materials.
DIES
STalacchia et al. (University of Navarra, San Sebastian, Spain.) Rev. de Metall., Vol 32, No 1, 1996, 18-24. Studies of M2, M2/3 and T42 modified with C and V are described. Cut-off dies were sintered in a N-H-CH4 atmosphere and a range of heat treatments were applied. A Vicker’s hardness of 1100 was attained in modified T42. Sintering shrinkages were also measured pi
Mechanical alloying, in air, of Fe-Zr powders and effects on structure and electrical properties were investigated with regard to use of acetone or ethanol additives during milling. Witlmut additives coercive force W;LS increased, Acetone init,ially increased coercive force which then declined with milling time increase. The additives enhanced formation of FeZrO,, compositrs from mixed Fe-Zr powders.
STEEL CUT-OFF TECHNIQUES
OF METAL MATRIX WITH DIAMOND
TOOLS
HSOberoi (Western Washington University USA.) Cutting Tool Neuis, No 2, 1996, B-10. Properties, structures and applications of metal matrix composites are discussed -with reference to difficulties in machining composites with very hard reinforcements. It is reported that the cutting behaviour of a range of diamond cutting tool materials, including polycrystalline diamond and diamond coated materials, had been compared with reference to tool life and wear characteristics.
etallic
T.Masumoto et al. (Tohoku University, Sendai, Japan.) J. Japan Sot. Powder Powder Metall., Vol 42, No 2, 1995, 175. 179. (In Japanese.) It is suggested that a pulse discharge resistance technique can be used to consolidate NiTi and TiAl under pseudoisostatic pressure to near net shape and near full density. The method used spherical graphite granules as the pressure transmitting medium.
KShibue
SINTERPNG
(Sumitomo
OF
Light
LIGHT
Metal
POWER ~~UR~~ENTS MECHANICAL MILLING INVESTIGATE ENERGY
Indus-
DUBING SFER
A.Iasonna, MMagini (ENEA-INN-NUMA, C.R.Casaccia, Rome, Italy.)Acla Mnter., Vol 44, No 3, 1996, 1109-1117. A model evaluation of energy transfer and power consumption during milling is presented with measurements of power consumption. Good agreement between predicted and experimental values is reported. Relationships between rotation speed, packing of the mill, energy transfer and power consumption are established. Practical consequences are illustrated.
POROUS SLEEVE OIL PERMEABILI
KMCielicki, KKrzeminski (University of Technology, Warsaw, Poland.) Int. J. Pow*der Metall., Vol 32, No 1, 1996, 175-183. Results of measurements of air and oil permeability for porous sleeve bearing materials are presented. Flow characteristics are simpler for air than oil. Pressure/flow rate is non-linear for air. Relationships between calculated and measured results are given. CONTACT INTELLIGENT BREAKER
materials
RMETALLIC
‘FIVE ~NT~~~~~~LICS
tries, Japan.) J. Japan Inst. fiigkt Metals, Vol44, No 11, X994, 614-621. (In Japanese.) Synthesis, structure and properties of aluminides are discussed and a model of reactive sintering is proposed. Pore reduction by HIP of TiAl and TiAlMn is considered. A range of fabrication methods is outlined. The importance of heat treatment is emphasized. It is shown that reactively sintered TiAlMn with additions of TiBz is better than a cast alloy.
MATERIALS FRAME
FOR CIRCIUT
Z.Mingjiang et al. (Electrical Equipment Scientific Research Inst., Guilin, China.) PM Technol., Vol 14, No 1, 1996, 30-36. (In Chinese.) Studies of W-Ag and Ag-Ni-graphite materials, with a presintered W skeleton, for heavy duty circuit breakers are reported. Arc burning and erosion testing were used. Paired contacts of W-5O%Ag/Ag-25%Ni-2!XC satisfy the requirements for most applications.
follow
are
of papers
which
were