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Adhesion of aluminium to tungsten carbide-cobalt tools
designed to improve interfacial bonding and to minimize thermal strcsscs.
Electrical and magnetic materials FORMATION OF CALCIUM TITANATE BY GRINDING CALCIUM OXIDE OR HYDROXIDE WITH TITANIUM OXIDE F.Saito et al. (Tohoku University, Sendai, Japan.) Powder Technol., Vnl 97, No 2, lYY8,178-182. It is reported that mechano-chemical synthesis of CaTiO,, ferroelectric ceramic: by grinding CaO or Ca(OH), with TiO,, as anatase or rutile, had been investigated. CaTiO, is shown to be easier to synthesize when CaO, rather than Ca(OH),, is ground with either form of TiO,. Heating at 625 to 925°C was found to be effective in crystallizing the CaTiO,. EFFECT OF HEAT TREATMENT ON WATER ATOMIZED ALNICO POWDER K.Kusaka et al. (Daido Inst. of Technology, Nagoya, Japan.) d Jpn Sot. Powder Powder Metall., Vol 44, No 5, 1997,495500. (In Japanese.) It is reported that ALNICO powders had been made by water atomization instead of the more usual method of casting and crushing. The magnetic properties were enhanced by heat treatment at 725 to 825°C for a short time. The atomized and heat-treated powder had properties similar to those of castcrushed material when made into resin bonded magnets and was cheaper to produce.
Hard materials steels
and tool
ADHESION OF ALUMINIUM TO TUNGSTEN CARBIDE-COBALT TOOLS N.Sato et al. (Fuji Die Co, Hadano, Japan.) d CJpn Sot. Powder Powder Metall., Vol 44. No 4, 1997, 365368. (In Japanese.) It is noted that Al tends to adhere to WC-Co cutting tools. This is discussed, and an investigation into the effects of WC particle size, %Co and tool roughness is described. Increase in any of these parameters increased the tendency for Al to adhere to the tool material.
lnterme tallic materials DIMENSIONAL CHANGES DURING REACTIVE SINTERING OF NICRELALUMINIUM-MOLYBDENUM POWDERS
A.Molinari et al. (University of Trento, Trento, Italy.) Powder Metall., Vol 40, No 4,1997,289-293. Dimensional changes during reactive sintering of Ni-Al-MO elemental powder mixtures were investigated. Sintering was in a dilatometer and at various heating rates. Contraction or expansion was found to depend on heating rate. It is concluded that intermetallic compounds were synthesized and that there was liquid phase sintering. Effects of process parameters on structure are discussed.
include separation of the inert gases, used for lamp filling, and use of halogens to prevent blackening, and reduced light transmission, of lamp envelopes. It is suggested that investigation of refractory metals will lead to other technological innovations.
COMPRESSIVE CREEP OF SPRAY FORMED PITANIUM ALUMINIDE
Finishing
E.J.Lavernia et al. (University of California, Irvine, USA. I Creep of spray formed PiAl, with a fine equiaxed fully lamellar microstructure, was investigated at 780 to 850°C and 180 to 320 MPa. A stress exponent of 4.3 and activation energy of 342 kJ.mol-’ wrere determined for the high stress-high temperature regime. The spray formed alloy had greater creep resistance than cast, heat treated material. This is discussed with respect to composition and structure. It is considered that fine interlamellar spacing may contribute to the higher creep resistance.
INFLUENCE OF HEAT TREATMENT AND COPPER INFILTRATION ON PROPERTIES OF PM PARTS
Powder injection moulding MODELLING THE INJECTION MOULDING PROCESS FOR METALS AND CERAMICS C.Griffn et al. (Lone Peak Engineering Inc, Utah, USA.) Powder Met&l., Vol 40, No 4,1997,248-249. It is reported that injection moulding of advanced materials had been combined with computer aided design flow modelling software in an approach which meets the requirements for production of lightweight parts.
Refractory
metals
USE OF REFRACTORY METALS IN COMPONENTS FOR LIGHT SOURCES G.Eichelbronner. (Osram GmbH, Munich, Germany.) Int. J. Refractory Metals Hard Mater.,Vol 16, No 1,1998,5-11. Applications of refractory metals, Zr, Hf, Nb, Ta, W, MO and Re, in light sources, are reviewed. Demands for replacement of ThO in W lamp metals and increased lamp efficacy and life are noted. Substitution of radioactive ThO is not an easy task. Uses of feather edged MO ribbon in halogen lamps and Nh cups in high pressure Na lamps is considered. Other aspects discussed
EURO PM’97. The Abstracts that follow are from papers presented at the European Conference on Advances in Structural Materials, which was held in Munich, Germany, in October 1997.
W.Kelley, H.Zhou. (Borg Warner Automotive, USA.) The effects of heat treatment methods and Cu infiltration on mechanical properties of sintered parts were discussed. Test and computer simulated data were compared, including fatigue performance related to variations in heat treatment and Cu infiltration methods. Factors involved in design optimization were noted. Parts up to 2-3 kg and larger were considered. Some recommendations were made about the approach to optimization based on lahoratory and industrial experiences. ONE-STEP DEWAXING AND PLASMA NITRIDING U.Huchel, S.Stramke. (Eltro GmbH, Germany.) Improvements in shape stability, wear and corrosion resistance of PM parts. due to plasma nitriding, were noted. The importance of nitriding onto a clean surface, free of oxide and residuals, to get a good result was emphasized. Some experiences involving dewaxing and plasma nitriding in a single step were described. MACHINABILITY TESTING OF PM STEELS F.Miani. (University of Udine, Italy.) A method for evaluation of machinability of sintered steels was proposed. Results of tests of materials made from diffusion bonded powders were presented and discussed. EFFECTS OF SHOT PEENING ON FATIGURE PROPERTIES OF STEELS S.Saritas, R.Varol. tGazi University, Turkey. ) Effects of shot peening on hardness, tensile and fatigue properties of sintered Fe, Fe-0.5%C, Fe-B%& and Fe0.5%C-2%Cu were investigated. Shot peening was carried out under a range
MPR November 1998 39
Electrical and magnetic materials FORMATION OF CALCIUM TITANATE BY GRINDING CALCIUM OXIDE OR HYDROXIDE WITH TITANIUM OXIDE F.Saito et al. (Tohoku University, Sendai, Japan.) Powder Technol., Vnl 97, No 2, lYY8,178-182. It is reported that mechano-chemical synthesis of CaTiO,, ferroelectric ceramic: by grinding CaO or Ca(OH), with TiO,, as anatase or rutile, had been investigated. CaTiO, is shown to be easier to synthesize when CaO, rather than Ca(OH),, is ground with either form of TiO,. Heating at 625 to 925°C was found to be effective in crystallizing the CaTiO,. EFFECT OF HEAT TREATMENT ON WATER ATOMIZED ALNICO POWDER K.Kusaka et al. (Daido Inst. of Technology, Nagoya, Japan.) d Jpn Sot. Powder Powder Metall., Vol 44, No 5, 1997,495500. (In Japanese.) It is reported that ALNICO powders had been made by water atomization instead of the more usual method of casting and crushing. The magnetic properties were enhanced by heat treatment at 725 to 825°C for a short time. The atomized and heat-treated powder had properties similar to those of castcrushed material when made into resin bonded magnets and was cheaper to produce.
Hard materials steels
and tool
ADHESION OF ALUMINIUM TO TUNGSTEN CARBIDE-COBALT TOOLS N.Sato et al. (Fuji Die Co, Hadano, Japan.) d CJpn Sot. Powder Powder Metall., Vol 44. No 4, 1997, 365368. (In Japanese.) It is noted that Al tends to adhere to WC-Co cutting tools. This is discussed, and an investigation into the effects of WC particle size, %Co and tool roughness is described. Increase in any of these parameters increased the tendency for Al to adhere to the tool material.
lnterme tallic materials DIMENSIONAL CHANGES DURING REACTIVE SINTERING OF NICRELALUMINIUM-MOLYBDENUM POWDERS
A.Molinari et al. (University of Trento, Trento, Italy.) Powder Metall., Vol 40, No 4,1997,289-293. Dimensional changes during reactive sintering of Ni-Al-MO elemental powder mixtures were investigated. Sintering was in a dilatometer and at various heating rates. Contraction or expansion was found to depend on heating rate. It is concluded that intermetallic compounds were synthesized and that there was liquid phase sintering. Effects of process parameters on structure are discussed.
include separation of the inert gases, used for lamp filling, and use of halogens to prevent blackening, and reduced light transmission, of lamp envelopes. It is suggested that investigation of refractory metals will lead to other technological innovations.
COMPRESSIVE CREEP OF SPRAY FORMED PITANIUM ALUMINIDE
Finishing
E.J.Lavernia et al. (University of California, Irvine, USA. I Creep of spray formed PiAl, with a fine equiaxed fully lamellar microstructure, was investigated at 780 to 850°C and 180 to 320 MPa. A stress exponent of 4.3 and activation energy of 342 kJ.mol-’ wrere determined for the high stress-high temperature regime. The spray formed alloy had greater creep resistance than cast, heat treated material. This is discussed with respect to composition and structure. It is considered that fine interlamellar spacing may contribute to the higher creep resistance.
INFLUENCE OF HEAT TREATMENT AND COPPER INFILTRATION ON PROPERTIES OF PM PARTS
Powder injection moulding MODELLING THE INJECTION MOULDING PROCESS FOR METALS AND CERAMICS C.Griffn et al. (Lone Peak Engineering Inc, Utah, USA.) Powder Met&l., Vol 40, No 4,1997,248-249. It is reported that injection moulding of advanced materials had been combined with computer aided design flow modelling software in an approach which meets the requirements for production of lightweight parts.
Refractory
metals
USE OF REFRACTORY METALS IN COMPONENTS FOR LIGHT SOURCES G.Eichelbronner. (Osram GmbH, Munich, Germany.) Int. J. Refractory Metals Hard Mater.,Vol 16, No 1,1998,5-11. Applications of refractory metals, Zr, Hf, Nb, Ta, W, MO and Re, in light sources, are reviewed. Demands for replacement of ThO in W lamp metals and increased lamp efficacy and life are noted. Substitution of radioactive ThO is not an easy task. Uses of feather edged MO ribbon in halogen lamps and Nh cups in high pressure Na lamps is considered. Other aspects discussed
EURO PM’97. The Abstracts that follow are from papers presented at the European Conference on Advances in Structural Materials, which was held in Munich, Germany, in October 1997.
W.Kelley, H.Zhou. (Borg Warner Automotive, USA.) The effects of heat treatment methods and Cu infiltration on mechanical properties of sintered parts were discussed. Test and computer simulated data were compared, including fatigue performance related to variations in heat treatment and Cu infiltration methods. Factors involved in design optimization were noted. Parts up to 2-3 kg and larger were considered. Some recommendations were made about the approach to optimization based on lahoratory and industrial experiences. ONE-STEP DEWAXING AND PLASMA NITRIDING U.Huchel, S.Stramke. (Eltro GmbH, Germany.) Improvements in shape stability, wear and corrosion resistance of PM parts. due to plasma nitriding, were noted. The importance of nitriding onto a clean surface, free of oxide and residuals, to get a good result was emphasized. Some experiences involving dewaxing and plasma nitriding in a single step were described. MACHINABILITY TESTING OF PM STEELS F.Miani. (University of Udine, Italy.) A method for evaluation of machinability of sintered steels was proposed. Results of tests of materials made from diffusion bonded powders were presented and discussed. EFFECTS OF SHOT PEENING ON FATIGURE PROPERTIES OF STEELS S.Saritas, R.Varol. tGazi University, Turkey. ) Effects of shot peening on hardness, tensile and fatigue properties of sintered Fe, Fe-0.5%C, Fe-B%& and Fe0.5%C-2%Cu were investigated. Shot peening was carried out under a range
MPR November 1998 39