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High density high speed steels
Literature combined with toughness of the bulk material required. Powder of a hardenable Ni-Cr-Mo-V steel mixed with varying amounts of CrB2 and TiB2 powder was used. Microstructure and m e c h a n i c a l p r o p e r t i e s including wear resistance were examined. Graded structures were produed and assessed. DEVELOPMENT OF SINTERED HIGH SPEED STEEL (HSS) ALLOYS FOR WEAR APPLICATIONS M Igharo, et al, (The Open University, Milton Keynes, UK). Vol 1, Paper 13,266-271. Dimensional stability, mechanical properties and microstructures ofPM HSS samples, some diluted with Fe, were examined after various processing conditions with the objective of assessing potential for wear resistant applications. Dimensional stability is impaired after sintering above 1200*C, due to formation of liquid phase and development of carbide grain boundary networks, resulting in a sharp fall in bend strength. Phenomena were explained in terms of resistance of carbide grains to dissolution. EFFECT OF TRACE ELEMENTS ON PRODUCTION AND PROPERTIES OF HARD METALS P Wilhartitz, et al, (Metallwerk-Plansee GmbH, Reutte, Austria). Vol 1, Paper 15, 289-296. The paper reports a literature survey on the effects of trace elements on structure and properties of carbide hard alloys. Elements were grouped according to effects, i.e. grain refiners, grain coarseners, pore forming elements and those with no reported effect during WO reduction, carburizing and sintering. Conflicting effects were reported. Applications of modern analytical techniques are reviewed. HIGH SPEED STEEL PRODUCED FROM REACTION SPRAY DRIED POWDERS R Marquart, K Humrnert, (Domier GmbH, Friedrichshafen, Germany). Vol 2, Paper 5, 20-24. A reaction spray dried powder has been used to produce a HSS. Uniform distribution of carbide phases, fine grained microstructure and high purity of powder consolidated materials are reported.
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BONDING BETWEEN TUNGSTEN AND OXIDE CERAMICS V Heinzel, et al, (Kernforschungzentrum Karlsruhe, Karlsruhe, Germany). Vol 2, Paper 13, 66-68. A brazing procedure was developed to bond oxide ceramic tool tips to W alloy shanks. Ni-Ti alloy was used as filler. To minimize thermal stresses at the interface, Nb foil was placed between W alloy and oxide parts. Satisfactory service is reported. PROPERTIES OF TOOL STEEL PRODUCED FROM OIL ATOMIZED POWDER B Schiborr, et al, (Technical University of Clausthal, Clausthal, Germany). Vol 2, Paper 21,103-106. Tool steels of compositions 1.4%C-1.4%Cr and 1.4%C-4.5%Cr-l.l%Mo-0.3%V were fabricated from oil atomized powders. Effect of heat during de-oiling is only small. Structure was observed as homogeneous, finely distributed carbides giving good mechanical properties. 02 content is limited to 300 ppm.
MECHANICAL BEHAVIOUR OF CERAMIC REINFORCED HIGH SPEED TOOL STEELS (HSS) R A Queeney, et al, (Pennsylvania State University, USA). Vol 2, Paper 22, 107-112. The potential of HSS reinforced with 1-0%A1203 was examined for wear resistance. Trends in strength and fracture resistance p a r a m e t e r s which may be relevant to mechanical design are delineated.
TRANSVERSE RUPTURE STRENGTH (TRS AND PLASTIC W O R K OF BENDING OF TWO PM TOOL STEELS P Beiss, R Wahling, (SintermetallwerkKrebsoge, Radevormwald, Germany). Vol 2, Paper 28, 140-143. Two tool steels were produced from spherical gas atomized powders by HIP and were tested in 3-point load bending after various heat treatments. TRS and plastic work of bending were found to be superior to conventional tool steels and some PM materials produced by other routes. Wear properties under mild
abrasive conditions are mainly determined by hardness and volume fraction of carbides.
PROCESSING VARIABLES AND FAILURE PROPERTIES OF WATER ATOMIZED SINTERED T15 HIGH SPEED STEELS M Santos, et al, (LNETI(DTM), Lumiar, Lisbon, Portugal). Vol 2, Paper 30, 155-158. Effects of small variations in process parameters on properties of T15 HSS were investigated. Specimens were produced from annealed water atomized T 15 HS S powder and subjected to a range of process routes. Transverse rupture strengths were measured and microstructure and fracture surfaces examined.
ALTERNATIVE PRODUCTION ROUTES TO HSS SEMI-FINISHED PRODUCTS P Ray, P K Pal, (Metallurgical and Engineering Consultants India) Ltd, Ranchi, India). Vol 2, Paper 31,159-169. The paper reviews processes for production of PM HSS and makes comparison with HSS produced by ingot metallurgy.
ENRICHMENT OF HIGH SPEED STEELS WITH HARD CERAMIC PARTICLES M M Rebbeck, et al, (University of Bradford, UK). Vol 2, Paper 35, 196-199. Three methods, powder blending, prealloying and infiltration, of producing ceramic particle reinforced HSS have been investigated. Various carbides, nitrides and oxides were used. Compacts were produced and it was found that most carbides and nitrides could be incorporated into a fully dense structure. Examples of microstructures are given. HIGH DENSITY HIGH SPEED STEELS G Greetham, (Manganese Bronze, Ipswich, UK). Vol 2, Paper 37,206-216. PM process variables applied to production of HSS have been studied with the objective of producing materials of high density. It is concluded that high density steels can be
MPR November 1990
Review produced by sintering at 1150°C using Cu and P as sintering aids. High transverse rupture strength is found to be possible after heat treatment. Densification is due to formation of liquid phases during sintering. MECHANISM OF LIQUID PHASE SINTERING IN HIGHER ALLOYED POWDER m THERMODYNAMIC ASPECTS M Sittner (National Institute for Materials, Prague, Czechoslovakia). Vol 2, Paper 41, 234-240. Additions of 5%Cu or Ni were made to M2 HSS powders. Powders were compacted and sintered at ll00*C or 1200°C respectively. Samples of cast M2 with Cu or Ni additions were prepared for comparison. Distribution of Cu and Ni in the PM and cast alloys was investigated.
METAL INJECTION MOULDING (MIM) FOR Ni-MICROALLOYED W POWDER
Tensile properties and mierostructure of PM Ti-48.2%AI-3%(Cr+Mn)-2%Nb (at%) were investigated. Samples were prepared from gas atomized powder alloy powder and fabricated by vacuum hot pressing and extrusion followed by heat treatment. Distribution of TiA1 and TiAI3 and microstructural features were correlated with tensile properties.
HIGH TEMPERATURE INTERMETALLIC ALLOYS AND INTERMETALLIC MATRIX COMPOSITES BY POWDER PROCESSING
R M German, et al, (Rennselaer Polytechnic Institute, Troy, New York, USA). Vol 1, Paper 18, 310-323. An account is given of the reactive processing ofNi, Ti and Nb aluminides. Processes involve a transient liquid phase and an exothermic reaction which occurs as the intermetallic compounds form from the elemental materials. The paper describes the effects of process variables with emphasis on Ni3A1. Use of aluminides as a matrix for composites is reviewed. Selection of suitable ceramic reinforcing material and whisker alignment in composites are matters of concern.
I-N Moon, et al, (Han-Yanl University, Seoul, Korea). Vol 1, Paper 26,385-391. MIM was used to consolidate W powder containing Ni for activated sintering. The binder used was methyl cellulose and water. Effects of binder characteristics on moulding behaviour were investigated and the optimum mix determined. The optimum mix was then c o n s o l i d a t e d , d e b o u n d and s i n t e r e d . Satisfactory processing was achieved with 18% m e t h y l c e l l u l o s e and 8% water. Debinding at 7500C gave complete removal of binder leaving only a trace of C. Relative density of more than 96% was attained.
MECHANICAL INTERMIXING AND ALLOYING OF INTERMETALLICS D G Morris, M A Morris, (University of Neuchatel, Switzerland). Vol 2, Paper 10, 47-51. The paper describes characteristics of mechanical alloying and advantages and problems of the process. Intermetallics, NiTi and FeA1 with added carbides are used as examples.
PROCESSING OF TiAI STRUCTURAL PARTS BY REACTION HIP OF PRECOMPACTED ELEMENTAL POWDERS MICROSTRUCTURE AND PROPERTIES OF A PM Ti ALUMINIDE ALLOY Y-W Kim, J J Kleek, (Wright-Patterson Air Force Base, Ohio, USA). Vol 1, Paper 14, 272-288.
MPR November 1990
W G S m a r s l y , M Dahms, ( M o t o r e n und-Turbinen-Union, Munich, Germany), Vol 2, Paper 17, 86-92. Reactive HIP has been used to process compacts of elemental Ti and AI powders into fully dense compacts. Process optimization
results in the production of parts with a fine and homogeneous microstructure. MECHANICAL PROPERTIES OF HOT PRESSED COMPACTS OF TiAI POWDER PRODUCED BY PLASMA ROTATING ELECTRODE PROCESS (PREP)
M Tokizane, et al, (Ritsumeiken University, Kyoto, Japan). Vol 2, Paper 18, 93-96. TiA1 powder was produced by PREP and by PREP and ball milling (PREP-BM). Powders were consolidated by vacuum hot pressing (VHP). PREP-BM material gave relative density above 99% on VHP at 1223K and 200MPa. The PREP powder required 1323K and 100MPa to attain this. Better mechanical properties were obtained with PREP-BM powder.
PREDICTION OF HIP PARAMETERS FOR Ar-ATOMIZED NiAlh POWDERS WITH STOICHIOMETRIC VARIATIONS
R Laag, et al, (Max-Planck Institute, Stuttgart, Germany). Vol. 2, Paper 50, 278-288. Powders of Ni aluminides, NiA1 and Ni3AI, were prepared by Ar-atomization with stoichiometric and non-stoichiometric compositions, and characterized. Deformation under load and thermal expansion by dilatometer were measured. HIP parameters were estimated from the measurements.
Mechanical Ai~oyi~lg ASSESSMENT OF MECHANICALLY ALLOYED (MA) AI ALLOYS P Le Brun, et al, (Leuven University, Heverlee, Belgium). Vol 2, Paper 1, 1--6. A1-5Fe-4Mn alloy was produced by MA. The stability of microstmcture and properties at each processing stage were assessed by metallography, differential thermal analysis, microhardness and mechanical testing. Improved properties due to fine structure and homogeneity up to 4000C are reported. Stability is due to inert dispersions introduced during MA and intermetallics formed during processing.
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790
BONDING BETWEEN TUNGSTEN AND OXIDE CERAMICS V Heinzel, et al, (Kernforschungzentrum Karlsruhe, Karlsruhe, Germany). Vol 2, Paper 13, 66-68. A brazing procedure was developed to bond oxide ceramic tool tips to W alloy shanks. Ni-Ti alloy was used as filler. To minimize thermal stresses at the interface, Nb foil was placed between W alloy and oxide parts. Satisfactory service is reported. PROPERTIES OF TOOL STEEL PRODUCED FROM OIL ATOMIZED POWDER B Schiborr, et al, (Technical University of Clausthal, Clausthal, Germany). Vol 2, Paper 21,103-106. Tool steels of compositions 1.4%C-1.4%Cr and 1.4%C-4.5%Cr-l.l%Mo-0.3%V were fabricated from oil atomized powders. Effect of heat during de-oiling is only small. Structure was observed as homogeneous, finely distributed carbides giving good mechanical properties. 02 content is limited to 300 ppm.
MECHANICAL BEHAVIOUR OF CERAMIC REINFORCED HIGH SPEED TOOL STEELS (HSS) R A Queeney, et al, (Pennsylvania State University, USA). Vol 2, Paper 22, 107-112. The potential of HSS reinforced with 1-0%A1203 was examined for wear resistance. Trends in strength and fracture resistance p a r a m e t e r s which may be relevant to mechanical design are delineated.
TRANSVERSE RUPTURE STRENGTH (TRS AND PLASTIC W O R K OF BENDING OF TWO PM TOOL STEELS P Beiss, R Wahling, (SintermetallwerkKrebsoge, Radevormwald, Germany). Vol 2, Paper 28, 140-143. Two tool steels were produced from spherical gas atomized powders by HIP and were tested in 3-point load bending after various heat treatments. TRS and plastic work of bending were found to be superior to conventional tool steels and some PM materials produced by other routes. Wear properties under mild
abrasive conditions are mainly determined by hardness and volume fraction of carbides.
PROCESSING VARIABLES AND FAILURE PROPERTIES OF WATER ATOMIZED SINTERED T15 HIGH SPEED STEELS M Santos, et al, (LNETI(DTM), Lumiar, Lisbon, Portugal). Vol 2, Paper 30, 155-158. Effects of small variations in process parameters on properties of T15 HSS were investigated. Specimens were produced from annealed water atomized T 15 HS S powder and subjected to a range of process routes. Transverse rupture strengths were measured and microstructure and fracture surfaces examined.
ALTERNATIVE PRODUCTION ROUTES TO HSS SEMI-FINISHED PRODUCTS P Ray, P K Pal, (Metallurgical and Engineering Consultants India) Ltd, Ranchi, India). Vol 2, Paper 31,159-169. The paper reviews processes for production of PM HSS and makes comparison with HSS produced by ingot metallurgy.
ENRICHMENT OF HIGH SPEED STEELS WITH HARD CERAMIC PARTICLES M M Rebbeck, et al, (University of Bradford, UK). Vol 2, Paper 35, 196-199. Three methods, powder blending, prealloying and infiltration, of producing ceramic particle reinforced HSS have been investigated. Various carbides, nitrides and oxides were used. Compacts were produced and it was found that most carbides and nitrides could be incorporated into a fully dense structure. Examples of microstructures are given. HIGH DENSITY HIGH SPEED STEELS G Greetham, (Manganese Bronze, Ipswich, UK). Vol 2, Paper 37,206-216. PM process variables applied to production of HSS have been studied with the objective of producing materials of high density. It is concluded that high density steels can be
MPR November 1990
Review produced by sintering at 1150°C using Cu and P as sintering aids. High transverse rupture strength is found to be possible after heat treatment. Densification is due to formation of liquid phases during sintering. MECHANISM OF LIQUID PHASE SINTERING IN HIGHER ALLOYED POWDER m THERMODYNAMIC ASPECTS M Sittner (National Institute for Materials, Prague, Czechoslovakia). Vol 2, Paper 41, 234-240. Additions of 5%Cu or Ni were made to M2 HSS powders. Powders were compacted and sintered at ll00*C or 1200°C respectively. Samples of cast M2 with Cu or Ni additions were prepared for comparison. Distribution of Cu and Ni in the PM and cast alloys was investigated.
METAL INJECTION MOULDING (MIM) FOR Ni-MICROALLOYED W POWDER
Tensile properties and mierostructure of PM Ti-48.2%AI-3%(Cr+Mn)-2%Nb (at%) were investigated. Samples were prepared from gas atomized powder alloy powder and fabricated by vacuum hot pressing and extrusion followed by heat treatment. Distribution of TiA1 and TiAI3 and microstructural features were correlated with tensile properties.
HIGH TEMPERATURE INTERMETALLIC ALLOYS AND INTERMETALLIC MATRIX COMPOSITES BY POWDER PROCESSING
R M German, et al, (Rennselaer Polytechnic Institute, Troy, New York, USA). Vol 1, Paper 18, 310-323. An account is given of the reactive processing ofNi, Ti and Nb aluminides. Processes involve a transient liquid phase and an exothermic reaction which occurs as the intermetallic compounds form from the elemental materials. The paper describes the effects of process variables with emphasis on Ni3A1. Use of aluminides as a matrix for composites is reviewed. Selection of suitable ceramic reinforcing material and whisker alignment in composites are matters of concern.
I-N Moon, et al, (Han-Yanl University, Seoul, Korea). Vol 1, Paper 26,385-391. MIM was used to consolidate W powder containing Ni for activated sintering. The binder used was methyl cellulose and water. Effects of binder characteristics on moulding behaviour were investigated and the optimum mix determined. The optimum mix was then c o n s o l i d a t e d , d e b o u n d and s i n t e r e d . Satisfactory processing was achieved with 18% m e t h y l c e l l u l o s e and 8% water. Debinding at 7500C gave complete removal of binder leaving only a trace of C. Relative density of more than 96% was attained.
MECHANICAL INTERMIXING AND ALLOYING OF INTERMETALLICS D G Morris, M A Morris, (University of Neuchatel, Switzerland). Vol 2, Paper 10, 47-51. The paper describes characteristics of mechanical alloying and advantages and problems of the process. Intermetallics, NiTi and FeA1 with added carbides are used as examples.
PROCESSING OF TiAI STRUCTURAL PARTS BY REACTION HIP OF PRECOMPACTED ELEMENTAL POWDERS MICROSTRUCTURE AND PROPERTIES OF A PM Ti ALUMINIDE ALLOY Y-W Kim, J J Kleek, (Wright-Patterson Air Force Base, Ohio, USA). Vol 1, Paper 14, 272-288.
MPR November 1990
W G S m a r s l y , M Dahms, ( M o t o r e n und-Turbinen-Union, Munich, Germany), Vol 2, Paper 17, 86-92. Reactive HIP has been used to process compacts of elemental Ti and AI powders into fully dense compacts. Process optimization
results in the production of parts with a fine and homogeneous microstructure. MECHANICAL PROPERTIES OF HOT PRESSED COMPACTS OF TiAI POWDER PRODUCED BY PLASMA ROTATING ELECTRODE PROCESS (PREP)
M Tokizane, et al, (Ritsumeiken University, Kyoto, Japan). Vol 2, Paper 18, 93-96. TiA1 powder was produced by PREP and by PREP and ball milling (PREP-BM). Powders were consolidated by vacuum hot pressing (VHP). PREP-BM material gave relative density above 99% on VHP at 1223K and 200MPa. The PREP powder required 1323K and 100MPa to attain this. Better mechanical properties were obtained with PREP-BM powder.
PREDICTION OF HIP PARAMETERS FOR Ar-ATOMIZED NiAlh POWDERS WITH STOICHIOMETRIC VARIATIONS
R Laag, et al, (Max-Planck Institute, Stuttgart, Germany). Vol. 2, Paper 50, 278-288. Powders of Ni aluminides, NiA1 and Ni3AI, were prepared by Ar-atomization with stoichiometric and non-stoichiometric compositions, and characterized. Deformation under load and thermal expansion by dilatometer were measured. HIP parameters were estimated from the measurements.
Mechanical Ai~oyi~lg ASSESSMENT OF MECHANICALLY ALLOYED (MA) AI ALLOYS P Le Brun, et al, (Leuven University, Heverlee, Belgium). Vol 2, Paper 1, 1--6. A1-5Fe-4Mn alloy was produced by MA. The stability of microstmcture and properties at each processing stage were assessed by metallography, differential thermal analysis, microhardness and mechanical testing. Improved properties due to fine structure and homogeneity up to 4000C are reported. Stability is due to inert dispersions introduced during MA and intermetallics formed during processing.
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