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Niobium compounds and alloys
strain rates. Elongation and reduction of area in tension were used to evaluate plasticity as a function of strain rate, stress distribution and dispersoiod content.
iron and steel MECHANICAL PROPERTIES OF POWDER FORGED STEEL WITH MEDIUM AND HIGH CARBON CONTENTS D. Yi, S. Xioaqiang (University of Science and Technology, Beijing, China) PIM Technology, Vol 12, No 1, 1994, 8-11. (In Chinese). Mechanical properties of Fe-Z%Ni0.5%Mo and Fe-2%Cu powder forged steels with medium to high carbon contents were investigated. Good combinations of properties are reported. The Ni-Mo-O.G%C steel had a tensile strength of 1570 MPa, a Rockwell hardness of 45C and impact toughness of 31 J.cm-‘. The Cu-O.G%Csteel had values of 1090 MPa, 41C and 38 J.cm-‘. These values are said to satis the requirements for structural parts. CONVENTIONAL PRESSING AND SINTERING OF STEELS CONTAINING ALUMINIUM J. Kazior et al (Polytechnika Krakowska, Krakow, Poland) Metal. Proszkow, Vol 27, No 2, 1994, 3-12. (In Polish). The application of PM to produce parts in steels containing Al, C and other metals is described. The process conditions are said to be pressing at 600 MPa and vacuum sintering at 1250 to 1300°C for 1 hour. The alloys lacked homogeneity with Vicker’s hardness in the range 100 to 400. The need to attain more homogeneous structures is emphasised. HEALING OF CREEP CAVITIES IN HEAT RESISTANT STEELS J. Kyono et al (National Research Inst. for Metals, Tokyo, Japan) J. Japan. Iron and Steel Znst.,Vol 79, No 5, 1993, 604-610. (In Japanese). Experimental results for creep cavity closure through heat treatment and compressive creep are reported for 1.3%Mn-0.5%Mo-0.5%Ni steel. It is reported that cavities sinter rapidly under compressive creep conditions but slowly during annealing alone. Two models are used to calculate the sintering rate which agreed well with experimental data. The results are discussed with reference to surface energy of creep cavities.
Nickel PROPERTIES OF MECHANICALLY ALLOYED ALUMINA AND YTTRIA DISPERSION STRENGTHENED NICKEL Y. Arami et al (Fukoda Metal Foil and Powder Co. Ltd., Kyoto, Japan) J.Japan 46
MPR May 1995
Sot. lurgy,
Powder
and
Powder
Metal-
Vol 40, No 12, 1993, 1179-1184. (In Japanese). It is reported that mechanical alloying had been used to disperse Alzo, or Y,Os in Ni powder. The powders are shown to have poor sinterability after short milling times and that this improved with longer milling. The Ni-A120s had better sinterability. Niobium NIOBIUM COMPOUNDS AND ALLOYS J. Eckert (H.C.Starck GmbH, Goslar, Germany) Znt. J. Refractory Metals & Hard Materials, Vol 12, No 6, 1993-1994, 335-340. Processes for the production of Nb alloys and compounds are summarized. New applications are suggested and the market for Nb alloys and compounds is discussed.
Tungsten PROCESSING AND PROPERTIES OF TUNGSTEN HEAVY ALLOYS WITH NICKEL-ALUMMIUM-IRON MATRIX S. Guha et al (Materials and Electrochemical Research Corp, Tucson, Arizona, USA.) Materials and Manuf Process., Vol 9, No 6, 1994, 1163-1187. The processing and properties of W heavy alloys with a Ni-40%Fe-12%Al matrix were investigated in order to assess the suitability as kinetic energy penetrators where a self-sharpening mechanism is required. Various proportions of W and matrix were studied and processing was optimized to give densities of 97.5%. The alloys are reported to exhibit the self-sharpening behaviour due to failure along adiabatic shear bands.
Ceramics SINTERING OF MONOLITHIC AND COMPOSITE NON-OXIDE CERAMICS S. Boskovic et al (Inst. of Nuclear Sciences Wnca’, Belgrade, Yugoslavia.) Science of Sin&ring, Vol 26, No 2, 19994, 127-143. A study of monolithic and composite ceramics based on Sic-AlN-SisN4 is described. The influence of quantity and viscosity of the liquid phase formed during sintering was investigated with regard to densification and properties. Examples are given to show how problems in the preparation of ceramic materials for special application can be solved.
Electrical and magnetic materials STRUCTURAL KINETICS IN AMORPHOUS IRON-BORON-SILICON ALLOYS M.M. Ristic et al (Serbian Academy of
Arts and Sciences, Belgrade, Yugoslavia) Science of Sir&ring, Vol 26, No 2, 1994, 205-209. An investigation of crystallization, at 5OO”C, and stability of the electron state of amorphous Fe-13at%B-5at%Si is described. Both processes are reported to take place in two stages and the kinetic and thermal parameters were determined. Changes in magnetic permeability and electrical resistivity are given together with the Curie temperatures. PREPARATION OF SAMARIUM-IRONNITROGEN PERMANENT MAGNET ALLOY WITH HIGH COERCMTY E. Liu et al Acta Metall. Sinica, Vol 29, No 3, 1993, B126-B129. (In Chinese). It is reported that mechanical alloying has been used to prepare Sm-Fe-N permanent magnet alloys with high coercive forces. It is suggested that MA in high power mills is the most effective method of preparing such alloys as it yields powder with small grain sizes.
Hard materials and tool steels SOLID SOLUBILITY OF TUNGSTEN AND TANTALUM CARBIDES IN TITANIUM CARBONITRIDE S. Zhang et al (Nanyang Technological University, Singapore) Znt. J. Refiactmy Metals & Hard Materials, Vol 12, No 6, 1993.1994, 329-333. An investigation in which Ti(C,N), TaC and WC were consolidated and heat treated to give (Ti,Ta,W) (C,N) solid solutions is described. The formation of the solid solution was monitored by changes in lattice parameters. WC was reported to dissolve and the lattice parameter of Ti(C,N) increased. Effects of temperatures and compaction pressures are described. The use of CIP gave less variation in the results. SERVICEABILITY OF STEEL BONDED HARDMETALS J. Kiibarsepp et al (Tallinn Technical University, Tallinn, Estonia) Znt. J. ReJi-actory Metals & Hard Materials, Vol 12, No 6, 1993-1994, 341-348. The use of steel to bond hardmetal cutting tool materials was investigated. Martensitic and austenitic steels and steels with intermediate structures were used as metallic binders in the study. Structures and mechanical properties were determined and comparisons are made with WC-Co and Tic- (Ni,Mo) hardmetals. STRUCTURAL CHARACTERISTICS OF RAPIDLY SOLIDIFIED HIGH SPEED STEELS V. Bodak et al (Technical University, Kosice, Slovak Republic) Pokroky Prmkove Metaluwe, No 1, 1994, 52-63. (In Czech).
iron and steel MECHANICAL PROPERTIES OF POWDER FORGED STEEL WITH MEDIUM AND HIGH CARBON CONTENTS D. Yi, S. Xioaqiang (University of Science and Technology, Beijing, China) PIM Technology, Vol 12, No 1, 1994, 8-11. (In Chinese). Mechanical properties of Fe-Z%Ni0.5%Mo and Fe-2%Cu powder forged steels with medium to high carbon contents were investigated. Good combinations of properties are reported. The Ni-Mo-O.G%C steel had a tensile strength of 1570 MPa, a Rockwell hardness of 45C and impact toughness of 31 J.cm-‘. The Cu-O.G%Csteel had values of 1090 MPa, 41C and 38 J.cm-‘. These values are said to satis the requirements for structural parts. CONVENTIONAL PRESSING AND SINTERING OF STEELS CONTAINING ALUMINIUM J. Kazior et al (Polytechnika Krakowska, Krakow, Poland) Metal. Proszkow, Vol 27, No 2, 1994, 3-12. (In Polish). The application of PM to produce parts in steels containing Al, C and other metals is described. The process conditions are said to be pressing at 600 MPa and vacuum sintering at 1250 to 1300°C for 1 hour. The alloys lacked homogeneity with Vicker’s hardness in the range 100 to 400. The need to attain more homogeneous structures is emphasised. HEALING OF CREEP CAVITIES IN HEAT RESISTANT STEELS J. Kyono et al (National Research Inst. for Metals, Tokyo, Japan) J. Japan. Iron and Steel Znst.,Vol 79, No 5, 1993, 604-610. (In Japanese). Experimental results for creep cavity closure through heat treatment and compressive creep are reported for 1.3%Mn-0.5%Mo-0.5%Ni steel. It is reported that cavities sinter rapidly under compressive creep conditions but slowly during annealing alone. Two models are used to calculate the sintering rate which agreed well with experimental data. The results are discussed with reference to surface energy of creep cavities.
Nickel PROPERTIES OF MECHANICALLY ALLOYED ALUMINA AND YTTRIA DISPERSION STRENGTHENED NICKEL Y. Arami et al (Fukoda Metal Foil and Powder Co. Ltd., Kyoto, Japan) J.Japan 46
MPR May 1995
Sot. lurgy,
Powder
and
Powder
Metal-
Vol 40, No 12, 1993, 1179-1184. (In Japanese). It is reported that mechanical alloying had been used to disperse Alzo, or Y,Os in Ni powder. The powders are shown to have poor sinterability after short milling times and that this improved with longer milling. The Ni-A120s had better sinterability. Niobium NIOBIUM COMPOUNDS AND ALLOYS J. Eckert (H.C.Starck GmbH, Goslar, Germany) Znt. J. Refractory Metals & Hard Materials, Vol 12, No 6, 1993-1994, 335-340. Processes for the production of Nb alloys and compounds are summarized. New applications are suggested and the market for Nb alloys and compounds is discussed.
Tungsten PROCESSING AND PROPERTIES OF TUNGSTEN HEAVY ALLOYS WITH NICKEL-ALUMMIUM-IRON MATRIX S. Guha et al (Materials and Electrochemical Research Corp, Tucson, Arizona, USA.) Materials and Manuf Process., Vol 9, No 6, 1994, 1163-1187. The processing and properties of W heavy alloys with a Ni-40%Fe-12%Al matrix were investigated in order to assess the suitability as kinetic energy penetrators where a self-sharpening mechanism is required. Various proportions of W and matrix were studied and processing was optimized to give densities of 97.5%. The alloys are reported to exhibit the self-sharpening behaviour due to failure along adiabatic shear bands.
Ceramics SINTERING OF MONOLITHIC AND COMPOSITE NON-OXIDE CERAMICS S. Boskovic et al (Inst. of Nuclear Sciences Wnca’, Belgrade, Yugoslavia.) Science of Sin&ring, Vol 26, No 2, 19994, 127-143. A study of monolithic and composite ceramics based on Sic-AlN-SisN4 is described. The influence of quantity and viscosity of the liquid phase formed during sintering was investigated with regard to densification and properties. Examples are given to show how problems in the preparation of ceramic materials for special application can be solved.
Electrical and magnetic materials STRUCTURAL KINETICS IN AMORPHOUS IRON-BORON-SILICON ALLOYS M.M. Ristic et al (Serbian Academy of
Arts and Sciences, Belgrade, Yugoslavia) Science of Sir&ring, Vol 26, No 2, 1994, 205-209. An investigation of crystallization, at 5OO”C, and stability of the electron state of amorphous Fe-13at%B-5at%Si is described. Both processes are reported to take place in two stages and the kinetic and thermal parameters were determined. Changes in magnetic permeability and electrical resistivity are given together with the Curie temperatures. PREPARATION OF SAMARIUM-IRONNITROGEN PERMANENT MAGNET ALLOY WITH HIGH COERCMTY E. Liu et al Acta Metall. Sinica, Vol 29, No 3, 1993, B126-B129. (In Chinese). It is reported that mechanical alloying has been used to prepare Sm-Fe-N permanent magnet alloys with high coercive forces. It is suggested that MA in high power mills is the most effective method of preparing such alloys as it yields powder with small grain sizes.
Hard materials and tool steels SOLID SOLUBILITY OF TUNGSTEN AND TANTALUM CARBIDES IN TITANIUM CARBONITRIDE S. Zhang et al (Nanyang Technological University, Singapore) Znt. J. Refiactmy Metals & Hard Materials, Vol 12, No 6, 1993.1994, 329-333. An investigation in which Ti(C,N), TaC and WC were consolidated and heat treated to give (Ti,Ta,W) (C,N) solid solutions is described. The formation of the solid solution was monitored by changes in lattice parameters. WC was reported to dissolve and the lattice parameter of Ti(C,N) increased. Effects of temperatures and compaction pressures are described. The use of CIP gave less variation in the results. SERVICEABILITY OF STEEL BONDED HARDMETALS J. Kiibarsepp et al (Tallinn Technical University, Tallinn, Estonia) Znt. J. ReJi-actory Metals & Hard Materials, Vol 12, No 6, 1993-1994, 341-348. The use of steel to bond hardmetal cutting tool materials was investigated. Martensitic and austenitic steels and steels with intermediate structures were used as metallic binders in the study. Structures and mechanical properties were determined and comparisons are made with WC-Co and Tic- (Ni,Mo) hardmetals. STRUCTURAL CHARACTERISTICS OF RAPIDLY SOLIDIFIED HIGH SPEED STEELS V. Bodak et al (Technical University, Kosice, Slovak Republic) Pokroky Prmkove Metaluwe, No 1, 1994, 52-63. (In Czech).