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Structure of NiMo alloys
terature Review RECRYSTALLIZATION BEHAVIOUR OF OXIDE DISPERSION STRENGTHENED (ODS) Fe ALLOYS
atmospheres. C content is higher at the surface in the nitrogen sintered specimens. It is c o n c l u d e d that pack c a r b u r i z i n g is economically feasible for sintered steels.
Germany), Powder Metallurgy htt.. Wo122,No 3, 1990, 33-34.
STRUCTURE AND PROPERTIES OF SINTERED PERMALLOY
PROPERTIES OF FINE AI203 RELATED TO METHOD OF PRECIPITATION
L Coheur, P Delavignette, (CEN/SCK, Boeretang, Mol, Belgium), ATB (Benelux) Metalhirgie. Three alloys of ODS Fe differing in composition and processing route were investigated. It was shown that a large elongated grain structure is easily obtained when the A1 concentration is high enough. The introduction of a cold deformation step is required to obtain the same structure at low concentrations of A1.
EFFECT OF VACUUM SINTERING ON MECHANICAL PROPERTIES OF STAINLESS STEEL CONTAINING Cu A Tiziani, et al, (University of Padova, Italy),
E M Minaev, Poroskovaya Metallurgia, 1989, No 11, 36--40, (in Russian). Porosity, electrical resistance, microstructure, phase composition and magnetic properties of permalloy made from a number of different starting materials were measured before and after heating in the range 500-13000C. Highest values of magnetic properties were obtained with alloys made from carbonyl powders.
Powder Metallurgy lnt, Vol 22, No 4, 1990, 17-19. Stainless steel, with and without 10%Cu, was vacuum sintered at different temperatures and for differing times. Differences in the microstructures between the alloys with and without Cu were attributed to differences in the oxide films on the steel powders which modify the solid-liquid interactions during sintering. Tensile and impact tests were done and differences in properties related to differences in microstructures.
EFFECTS OF ALLOYING ELEMENTS AND SINTERING ATMOSPHERE ON CASE CARBURIZATION OF POROUS STEEL M A Siddiqui, et al, (Z.H. College of Engineering and Technology, A M U Ailgarh, India), Powder Metallurgy Int., Vol 22, No 4, 1990, 19-22. Additions of l%Ni-2%Cu, 2%Ni-4%Cu, 1%Mo-2%Cu and 2%Mo-4%Cu were made to steels of two base compositions. Powders were compacted at 690 MPa and compacts were sintered at 1390°C in dissociated ammonia and a nitrogen based atmosphere. Sintered specimens were pack carburized for times in range 15-180 rain at temperatures between 1120-1175°C. Alloying with Ni, Mo and Cu increases surface hardness. Increase in P gives more clearly defined case depth. Case depth is similar for specimens sintered in both
MPR October 1990
A process for production of fine oxide ceramic powders by reaction of hydroxides in methanol is described. Organic phases are thermally decomposed to yield oxides of small particle size.
H K Varma, et al, (Regional Research Laboratory (CSIR), Trivandrum, India), Powder Metallurgy Int., Vol 22, No 3, 1990, 35-37. A1203 produced by precipitation from AI sulphate solution by urea reaction is compared with that produced by the NH3 method. Powders characterized by particle size and distribution, specific surface, tap density and morphology by SEM.
STRUCTURE OF Ni-Mo ALLOYS R A Barskaya, et al, Poroskovaya Metallurgia, 1989, No 11, 82-85, (in Russian). Optical and electron microscopy was used to study structure of corrosion resistant Ni-Mo alloy. Structural features observed included: inclusions of Ni4Mo at grain boundaries and segregations of carbides. These are said to result in increased corrosion resistance. STRENGTH AND WEAR RESISTANCE OF Ni-BASE ALLOYS A V P a u s t o v s k y , et al, Poroskovaya Metallurgia, 1990, No 2, 53-59, (in Russian). Structure of precipitation hardened and aggregate types of Ni-base alloys are studied for alloys with 0-5%TIC. Correlation between structure and wear resistance is found. Alloys with 2% TiC exhibited highest wear resistance.
SYNTHESIS OF OXIDE CERAMIC POWDERS IN METHANOL SOLUTIONS H Wedemeyer, D Vollath, (Kernforschungzentrum Karlsruhe GmbH, Karlsruhe,
PRODUCTION, PROPERTIES AND APPLICATIONS OF AI-NITRIDE PARTS K Hunold, (Elektroschmelzwerk Kempten, Kempten, Germany), Metall, Wol 44, No 3, 266-269, (in German). P r o d u c t i o n , properties and potential applications on AI nitrides are discussed. Advantages and disadvantages of these materials are reviewed from an engineering point of view.
USE OF PHYSICAL VAPOUR DEPOSITION (PVD) TO ENHANCE SURFACE PROPERTIES P Jewsbury, E D Doyle, (Materials Research Labs, Defence Science and Technology Organization, Ascott Vale, Australia), Materials Australia, Vol 22, No 4, 1990, 28-30. Methods of PVD are described. Applications in improvement of PM parts wear resistance in sliding wear are discussed.
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atmospheres. C content is higher at the surface in the nitrogen sintered specimens. It is c o n c l u d e d that pack c a r b u r i z i n g is economically feasible for sintered steels.
Germany), Powder Metallurgy htt.. Wo122,No 3, 1990, 33-34.
STRUCTURE AND PROPERTIES OF SINTERED PERMALLOY
PROPERTIES OF FINE AI203 RELATED TO METHOD OF PRECIPITATION
L Coheur, P Delavignette, (CEN/SCK, Boeretang, Mol, Belgium), ATB (Benelux) Metalhirgie. Three alloys of ODS Fe differing in composition and processing route were investigated. It was shown that a large elongated grain structure is easily obtained when the A1 concentration is high enough. The introduction of a cold deformation step is required to obtain the same structure at low concentrations of A1.
EFFECT OF VACUUM SINTERING ON MECHANICAL PROPERTIES OF STAINLESS STEEL CONTAINING Cu A Tiziani, et al, (University of Padova, Italy),
E M Minaev, Poroskovaya Metallurgia, 1989, No 11, 36--40, (in Russian). Porosity, electrical resistance, microstructure, phase composition and magnetic properties of permalloy made from a number of different starting materials were measured before and after heating in the range 500-13000C. Highest values of magnetic properties were obtained with alloys made from carbonyl powders.
Powder Metallurgy lnt, Vol 22, No 4, 1990, 17-19. Stainless steel, with and without 10%Cu, was vacuum sintered at different temperatures and for differing times. Differences in the microstructures between the alloys with and without Cu were attributed to differences in the oxide films on the steel powders which modify the solid-liquid interactions during sintering. Tensile and impact tests were done and differences in properties related to differences in microstructures.
EFFECTS OF ALLOYING ELEMENTS AND SINTERING ATMOSPHERE ON CASE CARBURIZATION OF POROUS STEEL M A Siddiqui, et al, (Z.H. College of Engineering and Technology, A M U Ailgarh, India), Powder Metallurgy Int., Vol 22, No 4, 1990, 19-22. Additions of l%Ni-2%Cu, 2%Ni-4%Cu, 1%Mo-2%Cu and 2%Mo-4%Cu were made to steels of two base compositions. Powders were compacted at 690 MPa and compacts were sintered at 1390°C in dissociated ammonia and a nitrogen based atmosphere. Sintered specimens were pack carburized for times in range 15-180 rain at temperatures between 1120-1175°C. Alloying with Ni, Mo and Cu increases surface hardness. Increase in P gives more clearly defined case depth. Case depth is similar for specimens sintered in both
MPR October 1990
A process for production of fine oxide ceramic powders by reaction of hydroxides in methanol is described. Organic phases are thermally decomposed to yield oxides of small particle size.
H K Varma, et al, (Regional Research Laboratory (CSIR), Trivandrum, India), Powder Metallurgy Int., Vol 22, No 3, 1990, 35-37. A1203 produced by precipitation from AI sulphate solution by urea reaction is compared with that produced by the NH3 method. Powders characterized by particle size and distribution, specific surface, tap density and morphology by SEM.
STRUCTURE OF Ni-Mo ALLOYS R A Barskaya, et al, Poroskovaya Metallurgia, 1989, No 11, 82-85, (in Russian). Optical and electron microscopy was used to study structure of corrosion resistant Ni-Mo alloy. Structural features observed included: inclusions of Ni4Mo at grain boundaries and segregations of carbides. These are said to result in increased corrosion resistance. STRENGTH AND WEAR RESISTANCE OF Ni-BASE ALLOYS A V P a u s t o v s k y , et al, Poroskovaya Metallurgia, 1990, No 2, 53-59, (in Russian). Structure of precipitation hardened and aggregate types of Ni-base alloys are studied for alloys with 0-5%TIC. Correlation between structure and wear resistance is found. Alloys with 2% TiC exhibited highest wear resistance.
SYNTHESIS OF OXIDE CERAMIC POWDERS IN METHANOL SOLUTIONS H Wedemeyer, D Vollath, (Kernforschungzentrum Karlsruhe GmbH, Karlsruhe,
PRODUCTION, PROPERTIES AND APPLICATIONS OF AI-NITRIDE PARTS K Hunold, (Elektroschmelzwerk Kempten, Kempten, Germany), Metall, Wol 44, No 3, 266-269, (in German). P r o d u c t i o n , properties and potential applications on AI nitrides are discussed. Advantages and disadvantages of these materials are reviewed from an engineering point of view.
USE OF PHYSICAL VAPOUR DEPOSITION (PVD) TO ENHANCE SURFACE PROPERTIES P Jewsbury, E D Doyle, (Materials Research Labs, Defence Science and Technology Organization, Ascott Vale, Australia), Materials Australia, Vol 22, No 4, 1990, 28-30. Methods of PVD are described. Applications in improvement of PM parts wear resistance in sliding wear are discussed.
721