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Gear fundamentals - a guide to PM gears
speed impact proceedure, with surface active agents was used to apply a submicron thick coating. A little of the coating flaked off. MICROSTRUCTURAL CHARACTERIZATION OF HIP CONSOLIDATED TRI-NICKEL ALUMINIDE P. Perez et al. Mater. Charact., Vol 33, No 4, 1994, 349-356. Production of NbsAl, doped with B, from RS powder by HIP is reported. Powder and consolidated material were characterized. The powder had a fine two-phase microstructure with dendrites of NiAl. The consolidated alloy was single phase. Mechanical
Metal
injection
moulding
COLD ISOSTATIC PRESSING OF
DEBOUND INJECTION MOULDED PART FOR IMPROVED PERFORMANCE I.H. Moon et al. (Hanyang University, Seoul, Korea.) J. Japan Sot. Powder and Powder Metallurgy, Vol 42, No 3, 1995, 347-352. (In English.) CIP is reported to have been used to increase the density of debound MIM parts. The parts were enclosed in a rubber membrane and CIP at 550 MPa. Sintered density was increased.
alloying
STRUCTURE OF MECHANICALLY ALLOYED NICKEL AND TITANIUMNICKEL/TITANIUM CARBIDE COMPOSITES H.Q. Ye et al. (Chinese Academy of Sciences, Shenyang, China.) Acta MateriaZZia, Vol 44, No 5, 1996, 1781-1792. The microstructures of MA TiNi-‘DC and Ni-TiC composite powders, prepared from elemental powders, were investigated. The powder was found to granulate to 3 to 10 mm after 3.5 hours MA. This is attributed to a melt-and-quench mechanism which was confirmed from the structures. Spherical TiC grains, with martensite and B2 structures were observed. It is suggested that self propagating synthesis occured initiated by heat of formation of Tic. MECILANICAL ALLOYING PROCESS DURING HIGH ENERGY BALL MILLING C. Kun et al. (Huazhong University of Science and Technology, Wuhan, China.) PM Technology, Vol 14, No 1, 1996, 2-7. In Chinese. MA of Fe and Ni powders in Ar was investigated with regard to microstructure and microhardness. Alloying is reported to be complete in 3 hours and the structure to be a mixture of body- and face-centred cubic phases. Further milling converted bee to fee. PROPERTIES OF ALUMINIUM COMPOSITES WITH SILICON CARBIDE S. Ryu et al. (Nihon University, Narashino, Japan.) J. Japan Inst. of Metals, Vol 60, No 2, 1996, 231-237. (In Japanese.) It is reported that Al-Sic composites, reinforced with particles or particles and whiskers, had been made. Sic, was incorporated by MA and SiC, was added by PM processing. Structures and properties were investigated. Both types of Sic were uniformly distributed. Sic, increased strength which was further
36
increased by MC,. With both values of 565 MPa and 105 GPa were found for tensile strength and elastic modulus.
MPR January
1997
EFFECTS OF FEEDSTOCK CHARACTERISTICS AND MOULDING CONDITIONS ON A DEFECT R. Miura et al. (Japan Steel Works Ltd, Muroran, Japan.) J. Japan Sot. Powder and Powder Metallurgy, Vol 42, No 3, 1995, 367-372. (In Japanese.) Defects in MIM parts were discussed with regard to factors involved and difficulty in predicting incidence of defects. The paper describes one defect, a crack in a thin walled part. Studies of process parameters, to eliminate the defect, are described.
PM
components
GEAR FUNDAMENTALS - A GUIDE TO PM GEARS G. Shturtz. Gear Technology, Vol 12, No 5, 1995, 26-28. The role of PM in manufacture of gear components is discussed with regard to alternative methods, cost effectiveness of PM and ready availability of a wide range of metals and alloy powders. Customized mixtures for a variety of ferrous and nonferrous materials, leading to specific mechanical properties are noted.
1996 WORLD CONGRESS ON POWDER METALLURGY. The abstracta which follow are from papers which were presented at the Congress, which ~89 held in Washington, D.C, USA, in June 1996.
Metal
injection
moulding
COMPOUNDING OF POWDER INJECTION MOULDING FEEDSTOCKS
P. Rieg. (Draiswerke, GmbH., Germany.) Machinery for preparing injection moulding feedstocks was discussed with regard to efficiency and economics. A
kneading extruder was described. This is a single stage continuous process. Examples were given, including ceramics and hardmetals. MECIIANICAL PROPERTIES OF ACRYLIC BASED INJECTION MOULDING FEEDSTOCRS J. Valencia et al. (Concurrent Technologies carp, USA) Acrylic based binders were reported to have been used in ceramic processing. These were shown to have high green strength, to give clean burnout and to be insensitive to humidity. Recent developments were described. Mechanical properties of parts made using the new binders were reviewed. DEVELOPMENT OF NEW BINDER SYSTEMS WITH IMPROVED PROPERTIES FOR POWDER INJECTION MOULDING M. Youseffi, LA Menzies. (Loughborough University of Technology, Loughborough, UK) The development of two new binder systems, with better moulding characteristics and which allow higher powder loadings, was described. One binder is baaed on a thermoplastic, wax plasticiser and lubricant. The other is a water based gelling binder, gelling agent and lubricant. Applications to ceramics, FeNi alloys, stainless steels and hardmetals were discussed. lsostatic
pressing
SIZE DISCS MADE FROM SUPERALLOY POWDERS BY DIRECT HIP ONLY LARGE
G.S. Genrikh. (All-Russian Inst of Light Alloys, Russia.) It was suggested that aerospace superalloy discs, 900 to 1150 mm diameter and 300 kg, could be made by HIP, subject to further developments in degassing and press technologies. The alloy considered was reported to have a tensile strength of 1600 MPa and a 100 hour rupture strengtbat 650°C of 1100 MPa. EFFECT OF HIP PROCESS VARIATIONS ON QUALITY OF NICKEL ALLOY DISCS
LV. Buslavsky et al. (All-Russian Inst of Light Alloys, Russia.) Investigations of the use of flow charts, heating to temperature followed by application of pressure, were described. Forming of a part and changes in structure and properties were studied for combinations of temperature and pressure. It was suggested that using a flow chart and preliminary heating allowed development of a more uniform structure in a superalloy than simultaneous application of heat and
Metal
injection
moulding
COLD ISOSTATIC PRESSING OF
DEBOUND INJECTION MOULDED PART FOR IMPROVED PERFORMANCE I.H. Moon et al. (Hanyang University, Seoul, Korea.) J. Japan Sot. Powder and Powder Metallurgy, Vol 42, No 3, 1995, 347-352. (In English.) CIP is reported to have been used to increase the density of debound MIM parts. The parts were enclosed in a rubber membrane and CIP at 550 MPa. Sintered density was increased.
alloying
STRUCTURE OF MECHANICALLY ALLOYED NICKEL AND TITANIUMNICKEL/TITANIUM CARBIDE COMPOSITES H.Q. Ye et al. (Chinese Academy of Sciences, Shenyang, China.) Acta MateriaZZia, Vol 44, No 5, 1996, 1781-1792. The microstructures of MA TiNi-‘DC and Ni-TiC composite powders, prepared from elemental powders, were investigated. The powder was found to granulate to 3 to 10 mm after 3.5 hours MA. This is attributed to a melt-and-quench mechanism which was confirmed from the structures. Spherical TiC grains, with martensite and B2 structures were observed. It is suggested that self propagating synthesis occured initiated by heat of formation of Tic. MECILANICAL ALLOYING PROCESS DURING HIGH ENERGY BALL MILLING C. Kun et al. (Huazhong University of Science and Technology, Wuhan, China.) PM Technology, Vol 14, No 1, 1996, 2-7. In Chinese. MA of Fe and Ni powders in Ar was investigated with regard to microstructure and microhardness. Alloying is reported to be complete in 3 hours and the structure to be a mixture of body- and face-centred cubic phases. Further milling converted bee to fee. PROPERTIES OF ALUMINIUM COMPOSITES WITH SILICON CARBIDE S. Ryu et al. (Nihon University, Narashino, Japan.) J. Japan Inst. of Metals, Vol 60, No 2, 1996, 231-237. (In Japanese.) It is reported that Al-Sic composites, reinforced with particles or particles and whiskers, had been made. Sic, was incorporated by MA and SiC, was added by PM processing. Structures and properties were investigated. Both types of Sic were uniformly distributed. Sic, increased strength which was further
36
increased by MC,. With both values of 565 MPa and 105 GPa were found for tensile strength and elastic modulus.
MPR January
1997
EFFECTS OF FEEDSTOCK CHARACTERISTICS AND MOULDING CONDITIONS ON A DEFECT R. Miura et al. (Japan Steel Works Ltd, Muroran, Japan.) J. Japan Sot. Powder and Powder Metallurgy, Vol 42, No 3, 1995, 367-372. (In Japanese.) Defects in MIM parts were discussed with regard to factors involved and difficulty in predicting incidence of defects. The paper describes one defect, a crack in a thin walled part. Studies of process parameters, to eliminate the defect, are described.
PM
components
GEAR FUNDAMENTALS - A GUIDE TO PM GEARS G. Shturtz. Gear Technology, Vol 12, No 5, 1995, 26-28. The role of PM in manufacture of gear components is discussed with regard to alternative methods, cost effectiveness of PM and ready availability of a wide range of metals and alloy powders. Customized mixtures for a variety of ferrous and nonferrous materials, leading to specific mechanical properties are noted.
1996 WORLD CONGRESS ON POWDER METALLURGY. The abstracta which follow are from papers which were presented at the Congress, which ~89 held in Washington, D.C, USA, in June 1996.
Metal
injection
moulding
COMPOUNDING OF POWDER INJECTION MOULDING FEEDSTOCKS
P. Rieg. (Draiswerke, GmbH., Germany.) Machinery for preparing injection moulding feedstocks was discussed with regard to efficiency and economics. A
kneading extruder was described. This is a single stage continuous process. Examples were given, including ceramics and hardmetals. MECIIANICAL PROPERTIES OF ACRYLIC BASED INJECTION MOULDING FEEDSTOCRS J. Valencia et al. (Concurrent Technologies carp, USA) Acrylic based binders were reported to have been used in ceramic processing. These were shown to have high green strength, to give clean burnout and to be insensitive to humidity. Recent developments were described. Mechanical properties of parts made using the new binders were reviewed. DEVELOPMENT OF NEW BINDER SYSTEMS WITH IMPROVED PROPERTIES FOR POWDER INJECTION MOULDING M. Youseffi, LA Menzies. (Loughborough University of Technology, Loughborough, UK) The development of two new binder systems, with better moulding characteristics and which allow higher powder loadings, was described. One binder is baaed on a thermoplastic, wax plasticiser and lubricant. The other is a water based gelling binder, gelling agent and lubricant. Applications to ceramics, FeNi alloys, stainless steels and hardmetals were discussed. lsostatic
pressing
SIZE DISCS MADE FROM SUPERALLOY POWDERS BY DIRECT HIP ONLY LARGE
G.S. Genrikh. (All-Russian Inst of Light Alloys, Russia.) It was suggested that aerospace superalloy discs, 900 to 1150 mm diameter and 300 kg, could be made by HIP, subject to further developments in degassing and press technologies. The alloy considered was reported to have a tensile strength of 1600 MPa and a 100 hour rupture strengtbat 650°C of 1100 MPa. EFFECT OF HIP PROCESS VARIATIONS ON QUALITY OF NICKEL ALLOY DISCS
LV. Buslavsky et al. (All-Russian Inst of Light Alloys, Russia.) Investigations of the use of flow charts, heating to temperature followed by application of pressure, were described. Forming of a part and changes in structure and properties were studied for combinations of temperature and pressure. It was suggested that using a flow chart and preliminary heating allowed development of a more uniform structure in a superalloy than simultaneous application of heat and