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Nickel free high strength sintered steels for mass production
M.Omori et al. (Tohoku University, Japan.) J. sot. Sendai, Jpn PowderlPowder Metall., Vol 46, No 3, 1999,269-276. (In Japanese.) Deposition, by spark plasma sintering, of a compositionally graded coating made up of ZrO,-Also,-410L stainless steel, is described. The graded coating is shown to be dense and free from cracks. Tribological properties were examined.
Composite
R.V.Curbaev et al. Fiz. Metal. Metalloued., Vol 87, No 2, 1999, 59-64. (In Russian.) 16 Ti-Cu alloys were prepared by mechanical alloying under a pressure of 5 GPa. It is reported that at 0 to lOat%Cu the structure was a hexagonal supersaturated solid solution of Cu in Ti. At 0 to lO%Ti the structure was cubic. Alloys in the range 50 to 8O%Cu were amorphous.
materials lntermetallic
IN SZTU SYNTHESIS OF TITANIUM DIBORIDE REINFORCED ALUMINIUM BY MECHANICAL ALLOYING
materials
GAS ATOMIZATION OF NICEEL ALUMINIDE POWDERS
L.Lu et al. (National University of Singapore, Singapore.) 2. Metallkd., Vol 80, No 8, 1998,567-572. (In English.) The possibility of synthesizing AlTiB, composites from elemental Al-Ti-B powders by high energy mechanical alloying was investigated. Only a TiB,like phase could be detected in the milled powder after at least 40 hours due to high strains in the powder. Heat treatment was required to form TiB, particulates in the Al particles. Mechanical properties increased with milling and sintering times.
A.Zambon et al. (University of Padua, Padua, Italy.) Powder Metall., Vol42, No 3, 1999,275-277. It is reported that NiAl and Ni,Al powders had been made by sonic N gas atomization. The powders were characterized for incidence of dendritic and equiaxed structures. This depended on particle size for NiAl but not for Ni,Al. Cooling rates are calculated. Contamination by N was measured and depended on particle size.
MECHANICAL PROPERTIES AND MICROSTRUCTURE OF PLATINUMYTTRIA COMPOSITES
NEAR NET SHAPE FORMING OF COMPONENTS FOR FUEL CALLS BY INDUCTION PLASMA SPRAYING
M.Besterci et al. (Ustav Materialoveho Vyskumu SAV, Kosice, Slovak Republic.) Pokroky Praskove Metal., Vol 37, No 1, 1999,38-45. (In Czech.) A study of Pt, dispersion strengthened with Y,O,, is described. It is shown that the composite has good mechanical properties, up to 700°C. The properties are discussed with reference to microstructural and fractographical analysis. The composite had a fine grain structure and low porosity.
E.Pross et al, J. Thermal Spray Technol., Vol8, No 1, 1999, 110-116. An investigation of radio frequency plasma spray forming, to make near net shape parts for fuel cells from PM powders, is described. The parts are complex in shape and have a channel structure, which must be gas tight, for passage of gas. This is attained by changing the spray angle, between 60 and 90”. Structures are evaluated.
Mechanical
alloying
RECENT DEVELOPMENTS IN MECHANICAL ACTIVATION AND MECHANO-SYNTHESIS
E.Gaffet et al. J. Mater. Chem., Vol 9, No 1, 1999,305-314. High energy ball milling, coupled with mechano-chemical synthesis, is reviewed with reference to changes in materials, possibly with subsequent use of thermal treatment. It is shown that Al,O,-(Fe,Ti) composites can be made from mechano-synthesized powders, for which the properties are described. HIGH PRESSURE ALLOYING
38
MECHANICAL
OF TITANIUM-COPPER
MPR September
2000
Spray
forming
PM’98 The following Abstracts are of papers that were presented at the 1998 Powder Metallurgy World Congress held in Granada, Spain, in October 1998.
of improving part quality and consistency without greatly increased cost. Properties of parts sintered in these gases were compared. NICKEL FREE HIGH STRENGTH SINTERED STEELS FOR MASS PRODUCTION
C.M.Sonsino. (Fraunhofer Inst., LBF, Germany.) A collaborative project between powder producers, parts makers and a research institute, into development of Ni free, high strength sintered steels, was described. The base for the study was a 4.O%Ni-1.5%Cu-0.5%Mo-O.G%C steel, pressed and sintered to 7.1 g.cmm3. The most promising alloy, with respect to processing, dimensional stability and mechanical properties, was reported to be a 3.O%Cr-0.5%Mo-0.5%Cu-0.3%C steel. MANUFACTURE OF PM STEELS WITH HIGH ACCURACY IN CARBON CONTENT
C.Molins et al. (AMES SA, Spain.) Investigations aimed at the production of steels, sintered at 1120 to 1250°C with an accuracy in %C of *0.05%, was described. Parameters influencing accuracy in %C!, atmosphere, sintering conditions, type of sintering furnace and avoidance of carburization and decarburization were studied. ANTI-ALLERGENIC STEELS
STAINLESS
M.A.Speidel et al. (ETH, Zurich, Switzerland. 1 Allergenic effects of Ni were discussed. The physical metallurgy of a new, Ni-free, austenitic stainless steel was described. Ni is replaced by N. The steel was reported to have good corrosion resistance and mechanical properties and be free of ferro-magnetism.
Hard
materials
INVESTIGATION OF INTERNAL SURFACES IN TUNGSTEN CARBIDE-
Steels NITROGEN BASE ATMOSPHERES FOR SINTERING CARBON STEEL PARTS
D.Garg et al. (Air Products and Chemical Inc, Allentown, USA. 1 Use of N atmospheres for sintering was reviewed with reference to endothermic gases and gases blended from N and H. ‘Endo-’ gas is widely used because of lower cost. Steel samples were sintered in either endo-gas or endo-gas diluted with N with the object
COBALT BY NEUTRON
SCATTERING
P.Harmat. (Hungarian Academy of Sciences, Budapest, Hungary.) An investigation of internal surfaces of WC grains in WC-Co, using a small angle neutron scattering technique was described. This was shown to reveal the average linear size of the morphology during sintering. The work was related to growth of WC grains during sintering. EUTECTIC TUNGSTEN
FORMATION
IN
CARBIDE-COBALT
Composite
R.V.Curbaev et al. Fiz. Metal. Metalloued., Vol 87, No 2, 1999, 59-64. (In Russian.) 16 Ti-Cu alloys were prepared by mechanical alloying under a pressure of 5 GPa. It is reported that at 0 to lOat%Cu the structure was a hexagonal supersaturated solid solution of Cu in Ti. At 0 to lO%Ti the structure was cubic. Alloys in the range 50 to 8O%Cu were amorphous.
materials lntermetallic
IN SZTU SYNTHESIS OF TITANIUM DIBORIDE REINFORCED ALUMINIUM BY MECHANICAL ALLOYING
materials
GAS ATOMIZATION OF NICEEL ALUMINIDE POWDERS
L.Lu et al. (National University of Singapore, Singapore.) 2. Metallkd., Vol 80, No 8, 1998,567-572. (In English.) The possibility of synthesizing AlTiB, composites from elemental Al-Ti-B powders by high energy mechanical alloying was investigated. Only a TiB,like phase could be detected in the milled powder after at least 40 hours due to high strains in the powder. Heat treatment was required to form TiB, particulates in the Al particles. Mechanical properties increased with milling and sintering times.
A.Zambon et al. (University of Padua, Padua, Italy.) Powder Metall., Vol42, No 3, 1999,275-277. It is reported that NiAl and Ni,Al powders had been made by sonic N gas atomization. The powders were characterized for incidence of dendritic and equiaxed structures. This depended on particle size for NiAl but not for Ni,Al. Cooling rates are calculated. Contamination by N was measured and depended on particle size.
MECHANICAL PROPERTIES AND MICROSTRUCTURE OF PLATINUMYTTRIA COMPOSITES
NEAR NET SHAPE FORMING OF COMPONENTS FOR FUEL CALLS BY INDUCTION PLASMA SPRAYING
M.Besterci et al. (Ustav Materialoveho Vyskumu SAV, Kosice, Slovak Republic.) Pokroky Praskove Metal., Vol 37, No 1, 1999,38-45. (In Czech.) A study of Pt, dispersion strengthened with Y,O,, is described. It is shown that the composite has good mechanical properties, up to 700°C. The properties are discussed with reference to microstructural and fractographical analysis. The composite had a fine grain structure and low porosity.
E.Pross et al, J. Thermal Spray Technol., Vol8, No 1, 1999, 110-116. An investigation of radio frequency plasma spray forming, to make near net shape parts for fuel cells from PM powders, is described. The parts are complex in shape and have a channel structure, which must be gas tight, for passage of gas. This is attained by changing the spray angle, between 60 and 90”. Structures are evaluated.
Mechanical
alloying
RECENT DEVELOPMENTS IN MECHANICAL ACTIVATION AND MECHANO-SYNTHESIS
E.Gaffet et al. J. Mater. Chem., Vol 9, No 1, 1999,305-314. High energy ball milling, coupled with mechano-chemical synthesis, is reviewed with reference to changes in materials, possibly with subsequent use of thermal treatment. It is shown that Al,O,-(Fe,Ti) composites can be made from mechano-synthesized powders, for which the properties are described. HIGH PRESSURE ALLOYING
38
MECHANICAL
OF TITANIUM-COPPER
MPR September
2000
Spray
forming
PM’98 The following Abstracts are of papers that were presented at the 1998 Powder Metallurgy World Congress held in Granada, Spain, in October 1998.
of improving part quality and consistency without greatly increased cost. Properties of parts sintered in these gases were compared. NICKEL FREE HIGH STRENGTH SINTERED STEELS FOR MASS PRODUCTION
C.M.Sonsino. (Fraunhofer Inst., LBF, Germany.) A collaborative project between powder producers, parts makers and a research institute, into development of Ni free, high strength sintered steels, was described. The base for the study was a 4.O%Ni-1.5%Cu-0.5%Mo-O.G%C steel, pressed and sintered to 7.1 g.cmm3. The most promising alloy, with respect to processing, dimensional stability and mechanical properties, was reported to be a 3.O%Cr-0.5%Mo-0.5%Cu-0.3%C steel. MANUFACTURE OF PM STEELS WITH HIGH ACCURACY IN CARBON CONTENT
C.Molins et al. (AMES SA, Spain.) Investigations aimed at the production of steels, sintered at 1120 to 1250°C with an accuracy in %C of *0.05%, was described. Parameters influencing accuracy in %C!, atmosphere, sintering conditions, type of sintering furnace and avoidance of carburization and decarburization were studied. ANTI-ALLERGENIC STEELS
STAINLESS
M.A.Speidel et al. (ETH, Zurich, Switzerland. 1 Allergenic effects of Ni were discussed. The physical metallurgy of a new, Ni-free, austenitic stainless steel was described. Ni is replaced by N. The steel was reported to have good corrosion resistance and mechanical properties and be free of ferro-magnetism.
Hard
materials
INVESTIGATION OF INTERNAL SURFACES IN TUNGSTEN CARBIDE-
Steels NITROGEN BASE ATMOSPHERES FOR SINTERING CARBON STEEL PARTS
D.Garg et al. (Air Products and Chemical Inc, Allentown, USA. 1 Use of N atmospheres for sintering was reviewed with reference to endothermic gases and gases blended from N and H. ‘Endo-’ gas is widely used because of lower cost. Steel samples were sintered in either endo-gas or endo-gas diluted with N with the object
COBALT BY NEUTRON
SCATTERING
P.Harmat. (Hungarian Academy of Sciences, Budapest, Hungary.) An investigation of internal surfaces of WC grains in WC-Co, using a small angle neutron scattering technique was described. This was shown to reveal the average linear size of the morphology during sintering. The work was related to growth of WC grains during sintering. EUTECTIC TUNGSTEN
FORMATION
IN
CARBIDE-COBALT