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A new hardmetal with nickel-cobalt binder for mining applications
sity, Montreal, Canada). Int. J. Refractory Metals Hard Mater, Vol 14, No 4, 1996, 257-262. Recrystallization of Ta-lOwt%W was investigated. Cold swaging was used to deform the alloy by 41-95% and the structure was heterogeneous with deformation bands. Effects of annealing temperatures and times on the proportion of recrystallized grains were determined in order to characterize the recrystallization behaviour.
Titanium MICROSTRUCTURE AND PIIASE RELATIONS IN POWDER PROCESSED TITANIUM-ALUMINIUM-NIOBIUM ALLOY S.G. Kumar, R.G. Reddy (University of Alabama, Tuscaloosa, USA). Metall. and Mater. Trans A, Vol 27A, No 4, 1996, 1121. 1126. An investigation of the effect of process route on the microstructure of Ti-22at%Al 12%Nb is described. Three process routes were used: cold pressing and reactive sintering; cold pressing; hot pressing and sintering; and arc melting, hydride-dehyride processing to make powder, CIP and sinterlng. The consolidated materials were characterized for microstructure. The first two methods gave lamellar structures. The third resulted in an equiaxed structure which is attributed to refinement due to the hydride-dehydrlde processing.
Tungsten PROPERTIES OF LOW TEMPERATURE SINTERED TUNGSTEN HEAVY ALLOY H. Jianzhong et al. (Central South University of Technology, Changsha, China). PM Technol., Vol 14, No 1, 1996, 37-43. (In Chinese.) Deformation, fracture, strength and corrosion characteristics of W-7% (Ni,Co) heavy alloys, sintered at 1240°C were investigated. At a grain size of 5 pm a tensile strength of 950 MPa was attained. The alloy is reported to have enhanced properties. CORRELATION BETWEEN TEMPERATURE DISTRIBUTION AND STRUCTURE OF SINTERED TUNGSTEN BARS M. Trzaska. (Warsaw University of Technology, Warsaw, Poland). Int. J. Refractory Metals Hard Mater., Vol 14, No 4, 1996, 235-243. A study of correlations between microstructure and temperature distribution in resistance sintered W bars is described, the object being to determine the structure. Sinterlng and temperature distribution are modelled. It is reported that non-uniform
temperatures during sintering are the main cause of structural variations.
Ceramics EFFECTS OF ADDITIONS ON SINTERING AND THERMAL DIFFUSMTY OF ALUMINIUM NITRIDE X. Li et al. (Iwate University, Iwate, Japan). Inst. Metals, Vol 60, No 2, 1996, 128-134. (In Japanese.) It is reported that the addition of up to 2Owt% of 300 nm A1-AlN powder to AlN powder, with YzOa as a sintering aid, reduces the temperature needed to sinter the AlN. Sintering was at 1700.1850°C. Two types of AlN powder, directly nitrided and carbothermally reacted, were used. The effect of addition of Al/AlN was greater with the direct nitrided powder. This effect is attributed to reaction between Al/AlN and the YzOa at low temperature. J. Japan
PM TECHNOLOGY OF URANIUM DIOXIDE NUCLEAR FUEL W. Zhiming (Yibin Nuclear Fuel Element Factory, Sichuan, China). PM Technol., Vol 14, No 1, 1996, 63-68. (In Chinese.) The production process and current status of bulk UOz, used as nuclear fuel, is described. Manufacturing technology is discussed with reference to PM. STRUCTURAL STUDY OF CERAMICS BASED ON BORON NITRIDE AFTER DETONATION TREATMENT T.V. Dobovik et al. Poroshkovaya Metallurgiya, No 5/6, 1995, 75-80. (In Russian.) Structural evolution during sintering of detonation compacted BN ceramic powders was investigated. The material is reported to contain wustite and sphalerite phases of BN and that a reversion to a graphite-like phase occured on sintering. Sintering at high temperatures, 1700.1950°C gave densities up to 95%.
Coatings CHANGE OF COMPOSITION AND STRUCTURE DURING FRICTION OF FLAME SPRAYED COATINGS V.F. Brltun et al. Poroshkovaya Metallurgiya, No 5/6, 1995, 80-85. (In Russian.) Structures of flame sprayed Cr coatings were studied before and after friction treatment. It is reported that the Cr became saturated with 0 during friction and secondary structures with a high defect density formed. The most stable structures are shown to be deformed initial Cr grains.
Composite
materials
trial Research
Japan). Vol 42, No 3, 1995, 318-322. (In Japanese.) An investigation of properties and structure of ceramic particle or whisker reinforced Al matrix composites is described. The composites were hot pressed at 700°C and sintered at 1250°C. The method is shown to be more effective for the whisker reinforced material. J. Japan
Inst., Hokkaido,
Sot. Powder
Powder
Metall.,
FORMATION OF TITANIUM CARBIDE DURING MECHANICAL ALLOYING OT CARBON-METAL POWDER MIXTURES K Yamada et al. Hyogo Prefectural Inst. of Industrial Research, Kobe, Japan). J. Japan Inst. of Metals, Vol 60, No 1, 1996, 100-105. (In Japanese.) It is reported that a TlC dispersed Mg alloy powder was prepared by MA of Mg-TiC mixtures followed by annealing at 500°C. The MA was monitored by X-ray spectroscopy. Stages identified are refinement of graphite and synthesis of Tic. Formation of Tic is enhanced by heat treatment but there is residual graphite.
Electrical and magnetic materials DYNAMIC COMPACTION OF AMORPHOUS NEODYMIUM-IRONBORON POWDERS Y. 8yono et al. (Tohoku University, Sendai, Japan). J. Japan Sot. Powder Powder Metall., Vol 42, No 3, 1995, 304-308. (In Japanese.) It is reported that amorphous Nd-Fe-B powders were made by mechanical grinding and melt spinning and dynamically compacted at lo-30 GPa. At 10 GPa the material was amorphous with low coercivity. At 20 GPa the NdzFeirB ferromagnetic phase formed. The melt spun powder contained clNdzFeirB.
Hard materials and tool steels ELECTROCHEMICAL ETCHING OF DIAMOND CONTAINING HARDMETAL TOOL STEELS AND DL4MOND RECOVERY M. Meszaros, K. Vadasdi. (Hungarian Academy of Sciences, Budapest, Hungary). Znt. J. Refractory Metals Hard Mater., Vol 14, No 4, 1996, 229-234. Methods for etching metal matrices with diamond grains are described. One method exposes diamond in WC-Co and the other removes metal from C steel tools. Both allow recovery of diamond particles from worn out tool. Effects of process conditions were established.
FABRICATION OF ALUMINIUMCERAMIC COMPOSITES BY HOT PRESSING
A NEW HARDMETAL WITH NICKELCOBALT BINDER FOR MINING APPLICATIONS
Y. Ueda et al. (Hokkaido National Indus-
Z. Ll, S. Baoqi (Central South University of
Titanium MICROSTRUCTURE AND PIIASE RELATIONS IN POWDER PROCESSED TITANIUM-ALUMINIUM-NIOBIUM ALLOY S.G. Kumar, R.G. Reddy (University of Alabama, Tuscaloosa, USA). Metall. and Mater. Trans A, Vol 27A, No 4, 1996, 1121. 1126. An investigation of the effect of process route on the microstructure of Ti-22at%Al 12%Nb is described. Three process routes were used: cold pressing and reactive sintering; cold pressing; hot pressing and sintering; and arc melting, hydride-dehyride processing to make powder, CIP and sinterlng. The consolidated materials were characterized for microstructure. The first two methods gave lamellar structures. The third resulted in an equiaxed structure which is attributed to refinement due to the hydride-dehydrlde processing.
Tungsten PROPERTIES OF LOW TEMPERATURE SINTERED TUNGSTEN HEAVY ALLOY H. Jianzhong et al. (Central South University of Technology, Changsha, China). PM Technol., Vol 14, No 1, 1996, 37-43. (In Chinese.) Deformation, fracture, strength and corrosion characteristics of W-7% (Ni,Co) heavy alloys, sintered at 1240°C were investigated. At a grain size of 5 pm a tensile strength of 950 MPa was attained. The alloy is reported to have enhanced properties. CORRELATION BETWEEN TEMPERATURE DISTRIBUTION AND STRUCTURE OF SINTERED TUNGSTEN BARS M. Trzaska. (Warsaw University of Technology, Warsaw, Poland). Int. J. Refractory Metals Hard Mater., Vol 14, No 4, 1996, 235-243. A study of correlations between microstructure and temperature distribution in resistance sintered W bars is described, the object being to determine the structure. Sinterlng and temperature distribution are modelled. It is reported that non-uniform
temperatures during sintering are the main cause of structural variations.
Ceramics EFFECTS OF ADDITIONS ON SINTERING AND THERMAL DIFFUSMTY OF ALUMINIUM NITRIDE X. Li et al. (Iwate University, Iwate, Japan). Inst. Metals, Vol 60, No 2, 1996, 128-134. (In Japanese.) It is reported that the addition of up to 2Owt% of 300 nm A1-AlN powder to AlN powder, with YzOa as a sintering aid, reduces the temperature needed to sinter the AlN. Sintering was at 1700.1850°C. Two types of AlN powder, directly nitrided and carbothermally reacted, were used. The effect of addition of Al/AlN was greater with the direct nitrided powder. This effect is attributed to reaction between Al/AlN and the YzOa at low temperature. J. Japan
PM TECHNOLOGY OF URANIUM DIOXIDE NUCLEAR FUEL W. Zhiming (Yibin Nuclear Fuel Element Factory, Sichuan, China). PM Technol., Vol 14, No 1, 1996, 63-68. (In Chinese.) The production process and current status of bulk UOz, used as nuclear fuel, is described. Manufacturing technology is discussed with reference to PM. STRUCTURAL STUDY OF CERAMICS BASED ON BORON NITRIDE AFTER DETONATION TREATMENT T.V. Dobovik et al. Poroshkovaya Metallurgiya, No 5/6, 1995, 75-80. (In Russian.) Structural evolution during sintering of detonation compacted BN ceramic powders was investigated. The material is reported to contain wustite and sphalerite phases of BN and that a reversion to a graphite-like phase occured on sintering. Sintering at high temperatures, 1700.1950°C gave densities up to 95%.
Coatings CHANGE OF COMPOSITION AND STRUCTURE DURING FRICTION OF FLAME SPRAYED COATINGS V.F. Brltun et al. Poroshkovaya Metallurgiya, No 5/6, 1995, 80-85. (In Russian.) Structures of flame sprayed Cr coatings were studied before and after friction treatment. It is reported that the Cr became saturated with 0 during friction and secondary structures with a high defect density formed. The most stable structures are shown to be deformed initial Cr grains.
Composite
materials
trial Research
Japan). Vol 42, No 3, 1995, 318-322. (In Japanese.) An investigation of properties and structure of ceramic particle or whisker reinforced Al matrix composites is described. The composites were hot pressed at 700°C and sintered at 1250°C. The method is shown to be more effective for the whisker reinforced material. J. Japan
Inst., Hokkaido,
Sot. Powder
Powder
Metall.,
FORMATION OF TITANIUM CARBIDE DURING MECHANICAL ALLOYING OT CARBON-METAL POWDER MIXTURES K Yamada et al. Hyogo Prefectural Inst. of Industrial Research, Kobe, Japan). J. Japan Inst. of Metals, Vol 60, No 1, 1996, 100-105. (In Japanese.) It is reported that a TlC dispersed Mg alloy powder was prepared by MA of Mg-TiC mixtures followed by annealing at 500°C. The MA was monitored by X-ray spectroscopy. Stages identified are refinement of graphite and synthesis of Tic. Formation of Tic is enhanced by heat treatment but there is residual graphite.
Electrical and magnetic materials DYNAMIC COMPACTION OF AMORPHOUS NEODYMIUM-IRONBORON POWDERS Y. 8yono et al. (Tohoku University, Sendai, Japan). J. Japan Sot. Powder Powder Metall., Vol 42, No 3, 1995, 304-308. (In Japanese.) It is reported that amorphous Nd-Fe-B powders were made by mechanical grinding and melt spinning and dynamically compacted at lo-30 GPa. At 10 GPa the material was amorphous with low coercivity. At 20 GPa the NdzFeirB ferromagnetic phase formed. The melt spun powder contained clNdzFeirB.
Hard materials and tool steels ELECTROCHEMICAL ETCHING OF DIAMOND CONTAINING HARDMETAL TOOL STEELS AND DL4MOND RECOVERY M. Meszaros, K. Vadasdi. (Hungarian Academy of Sciences, Budapest, Hungary). Znt. J. Refractory Metals Hard Mater., Vol 14, No 4, 1996, 229-234. Methods for etching metal matrices with diamond grains are described. One method exposes diamond in WC-Co and the other removes metal from C steel tools. Both allow recovery of diamond particles from worn out tool. Effects of process conditions were established.
FABRICATION OF ALUMINIUMCERAMIC COMPOSITES BY HOT PRESSING
A NEW HARDMETAL WITH NICKELCOBALT BINDER FOR MINING APPLICATIONS
Y. Ueda et al. (Hokkaido National Indus-
Z. Ll, S. Baoqi (Central South University of