- Email: [email protected]
Electroconducting metalsilicate materials
was reported that alloys of near full density, with ideal microstructures and high mechanical properties, were produced. Depending on temperature attained, WC and W grains were shown to be plastically deformed, giving high hardness.
Compaction
parameters
RAPID NON-DESTRUCTIVE DETERMINATION OF ENVELOPE DENSITY H.D.Stanley. (Micrometrics Instrument Corp., USA) The volume of a porous body was discussed with regard to total pore volume and total solids volume, which are engineering parameters, which influence performance and stability. It was noted that methods to determine total void volume are time consuming and may be inaccurate. A device for rapid, reproducible measurement of void volume was described. INFLUENCE ON SHRINK PM DIES
OF TEMPERATURE FITTING PRESSURE
OF
G.F.Bocchini et al. (Hans Italia SRL, Rapallo, Italy.) Pressures involved in shrink fitting and proceedures for assembly of PM dies were discussed and some calculations outlined. The need for knowledge of temperature effects on properties, fatigue properties and safety factors was noted in respect of tool reliability and demands imposed by use of warm compaction. Temperature effects on elasticity were reviewed. Die design criteria were established to avoid tool failure. Applications to a range of materials were described. MULTIPLE JET SOLIDIFICATION PROCESS FOR RAPID PROTOTYPING OF METAL AND CERAMIC PARTS
monitor property changes in an Fe compact d.uring uniaxial pressing, loading and unloading. It was concluded that pressure welding between particles caunsed lthe compact to behave as a sintered part. This w& justified by good agreement between elasticity data, data from sintered materials and model predictions. Partial de-welding during unloading was held to be responsible for low green properties. GENERALIZATION OF MICROHPLRDNESS AND LOCAL DENSITY YARIATIONS TO POWDER MATERIALS M. Guillot et al. (Laval University, Canada.) Density gradients, a common problem in green and sintered compacts, were discussed with regard to measurement of these and associated difficulties. The use of Vicker’s, microhardness was investigated for green and sintered 316L stainless steel and the method described. Guidlines for the technique and two applications were presented. RESONANT INSPECTION DESTRUCTIVE TESTING FOR
Non-destructive
evaluation
PM INDUSTRY
D.K. Foley. (Magnaflux, USA) A new non-destructive testing technique, resonant inspection, was reported. The method could be used to detect a range of defects in PM parts and was shown to be rapid, to be compatible with computerized accept/reject criteria and to require No chemicals, magnetization or radiation. The method is based on the fact that every object has a characteristic resonance pattern from which deviations indicate a flaw.
Electronic LONG
M.Greul et al. (Fraunhofer Inst.-IFAM, Germany.) The need for rapid production of prototypes was discussed with reference to part complexity, part variants and short delivery times. It was reported that Multiphase Jet Solidification had been developed for metal and ceramic parts. The process uses a powder/binder mix which is squirted through computer controlled nozzles, the part being built up layer by layer as it solidifies. The part is debound and sintered.
- A NEW NONTECHNOLOGY
AND
materials SHORT
PERFORMANCE VARISTOB
PULSE
OF ZINC OXIDE
production and applications. The object of the investigations was to eliminate defects found in metal-ceramic materials. Metalsilicate materials were reported to have been fabricated from cleaned metal powders and dispersed silicates. EURO PM’96.The foIIawing abstracts are fkom papers which were presented at the Confere:nce on Advances in Hard Materials Production which was held in Stockholm in May
Processing A PRACTICAL
ULTRASONIC EVALUATION OF IRON POWDER DURING COMPACTION
ELECTROCONDUCTING SILICATE MATERIALS
L.Piche et al. (Industrial Materials Inst., Canada.) It was reported that a non-destructive ultrasonic technique had been used to
M.G. Galuzinskiy. (Scientific Research Inst. on Binders and Materials, Ukraine.) Electroconducting metal/silicate materials were discussed with respect to
METAL
TO HARDMETAL
S.G. Moseley et al. (Edgar Allen Danite Ltd., Sheffield, UK) The whole process of making hardmetals from raw material to finished part was outlined. The underlying science was considered and some less common methods were noted. Some topics considered were control of grain size and carbon content, compaction methods, tooling, pre-sintering and sintering, process variables and finishing and joining methods DEVELOPMENT OF FUNCTIONALLY GRADEDED SINTEREIE HARD MATERIALS Electric InA. Ikegaya et al. (Sumitomo dustries Ltd., Japan.) The concept of functionally graded materials was reported to have been used in hardmetal production. The material comprised a Ti base ceramic surface, a cemented carbide sulbstrate and an intermediate layer. The material was shown to have abrasion and 6xcture properties superior to conventional cermets and to be less subject to exfoliation. GRAIN
SIZE
OF TITANIUM
R. Puyane et al. (Harris Corp., Republic of Ireland.) Pressing of ZNo blocks, for varistor use, by a double action compaction technique, was discussed with regard to effects of process varriables on properties. Dwell times were considered to be important as this allows particle rearrangement and ejection of entrapped gases. Study of the effects of this was described. Dwell time was reported to influence performance of ZnO varistors leaving scope for process optimization.
GUIDE
MANUFACTURE
CONTROL
IN SYNTHESIS
AND ZIRCONIUM
CARBIDES
L.M. Berger, L.Eckart. (Fraunhofer Inst., IKTS, Germany.) Applications of group IVA carbides, such as ZrC and Tic, were discussed. For improved properties fine grain size and narrow particle size distribution are required. Synthesis of Tic and ZrC from ZrOP-C and Ti02-C mixtures was investigated. From reaction mechanisms a means of grain size control was established. Structure of the C used was more influential than oxide powder type and various grades of C were investigated. Efforts to find a correlation between C structures and reactivity were made. It was shown that grain size and particle size distribution could be controlled by selection of raw materials and process conditions.
MPR January
1997 39
Compaction
parameters
RAPID NON-DESTRUCTIVE DETERMINATION OF ENVELOPE DENSITY H.D.Stanley. (Micrometrics Instrument Corp., USA) The volume of a porous body was discussed with regard to total pore volume and total solids volume, which are engineering parameters, which influence performance and stability. It was noted that methods to determine total void volume are time consuming and may be inaccurate. A device for rapid, reproducible measurement of void volume was described. INFLUENCE ON SHRINK PM DIES
OF TEMPERATURE FITTING PRESSURE
OF
G.F.Bocchini et al. (Hans Italia SRL, Rapallo, Italy.) Pressures involved in shrink fitting and proceedures for assembly of PM dies were discussed and some calculations outlined. The need for knowledge of temperature effects on properties, fatigue properties and safety factors was noted in respect of tool reliability and demands imposed by use of warm compaction. Temperature effects on elasticity were reviewed. Die design criteria were established to avoid tool failure. Applications to a range of materials were described. MULTIPLE JET SOLIDIFICATION PROCESS FOR RAPID PROTOTYPING OF METAL AND CERAMIC PARTS
monitor property changes in an Fe compact d.uring uniaxial pressing, loading and unloading. It was concluded that pressure welding between particles caunsed lthe compact to behave as a sintered part. This w& justified by good agreement between elasticity data, data from sintered materials and model predictions. Partial de-welding during unloading was held to be responsible for low green properties. GENERALIZATION OF MICROHPLRDNESS AND LOCAL DENSITY YARIATIONS TO POWDER MATERIALS M. Guillot et al. (Laval University, Canada.) Density gradients, a common problem in green and sintered compacts, were discussed with regard to measurement of these and associated difficulties. The use of Vicker’s, microhardness was investigated for green and sintered 316L stainless steel and the method described. Guidlines for the technique and two applications were presented. RESONANT INSPECTION DESTRUCTIVE TESTING FOR
Non-destructive
evaluation
PM INDUSTRY
D.K. Foley. (Magnaflux, USA) A new non-destructive testing technique, resonant inspection, was reported. The method could be used to detect a range of defects in PM parts and was shown to be rapid, to be compatible with computerized accept/reject criteria and to require No chemicals, magnetization or radiation. The method is based on the fact that every object has a characteristic resonance pattern from which deviations indicate a flaw.
Electronic LONG
M.Greul et al. (Fraunhofer Inst.-IFAM, Germany.) The need for rapid production of prototypes was discussed with reference to part complexity, part variants and short delivery times. It was reported that Multiphase Jet Solidification had been developed for metal and ceramic parts. The process uses a powder/binder mix which is squirted through computer controlled nozzles, the part being built up layer by layer as it solidifies. The part is debound and sintered.
- A NEW NONTECHNOLOGY
AND
materials SHORT
PERFORMANCE VARISTOB
PULSE
OF ZINC OXIDE
production and applications. The object of the investigations was to eliminate defects found in metal-ceramic materials. Metalsilicate materials were reported to have been fabricated from cleaned metal powders and dispersed silicates. EURO PM’96.The foIIawing abstracts are fkom papers which were presented at the Confere:nce on Advances in Hard Materials Production which was held in Stockholm in May
Processing A PRACTICAL
ULTRASONIC EVALUATION OF IRON POWDER DURING COMPACTION
ELECTROCONDUCTING SILICATE MATERIALS
L.Piche et al. (Industrial Materials Inst., Canada.) It was reported that a non-destructive ultrasonic technique had been used to
M.G. Galuzinskiy. (Scientific Research Inst. on Binders and Materials, Ukraine.) Electroconducting metal/silicate materials were discussed with respect to
METAL
TO HARDMETAL
S.G. Moseley et al. (Edgar Allen Danite Ltd., Sheffield, UK) The whole process of making hardmetals from raw material to finished part was outlined. The underlying science was considered and some less common methods were noted. Some topics considered were control of grain size and carbon content, compaction methods, tooling, pre-sintering and sintering, process variables and finishing and joining methods DEVELOPMENT OF FUNCTIONALLY GRADEDED SINTEREIE HARD MATERIALS Electric InA. Ikegaya et al. (Sumitomo dustries Ltd., Japan.) The concept of functionally graded materials was reported to have been used in hardmetal production. The material comprised a Ti base ceramic surface, a cemented carbide sulbstrate and an intermediate layer. The material was shown to have abrasion and 6xcture properties superior to conventional cermets and to be less subject to exfoliation. GRAIN
SIZE
OF TITANIUM
R. Puyane et al. (Harris Corp., Republic of Ireland.) Pressing of ZNo blocks, for varistor use, by a double action compaction technique, was discussed with regard to effects of process varriables on properties. Dwell times were considered to be important as this allows particle rearrangement and ejection of entrapped gases. Study of the effects of this was described. Dwell time was reported to influence performance of ZnO varistors leaving scope for process optimization.
GUIDE
MANUFACTURE
CONTROL
IN SYNTHESIS
AND ZIRCONIUM
CARBIDES
L.M. Berger, L.Eckart. (Fraunhofer Inst., IKTS, Germany.) Applications of group IVA carbides, such as ZrC and Tic, were discussed. For improved properties fine grain size and narrow particle size distribution are required. Synthesis of Tic and ZrC from ZrOP-C and Ti02-C mixtures was investigated. From reaction mechanisms a means of grain size control was established. Structure of the C used was more influential than oxide powder type and various grades of C were investigated. Efforts to find a correlation between C structures and reactivity were made. It was shown that grain size and particle size distribution could be controlled by selection of raw materials and process conditions.
MPR January
1997 39