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Bend properties of nickel-alumina micro-infiltrated macro-laminated composite
PM
of automotive gears was described. The results of s t u d i e s of bevel gears were p r e s e n t e d . Good c o r r e l a t i o n b e t w e e n p o r o s i t y a n d w e a r c h a r a c t e r i s t i c s was reported. Comparison was made with the same p a r t m a d e by forging.
Metal injection moulding INJECTION MOULDING OF HARDMETALS USING AN POLYACETYL BASED B I N D E R J.S. Ebenhoch, W. Hesse (BASF AG, Ludwigshafen, Germany). P r o b l e m s a r i s i n g in t h e MIM o f h a r d m e t a l s were discussed, the use of a polyacetyl b a s e d b i n d e r a n d c a t a l y t i c debinding, developed for hardmetals, was described. Properties and microstructures of injection moulded WC-Co were p r e s e n t e d and discussed with respect to the influence of f e e d s t o c k c o m p o s i t i o n a n d p r o c e s s variables. R U N N E R L E S S SYSTEMS FOR PROCESSING POLYMERS WITH A HEAVY LOADING OF METAL POWDER D.J. Seres (Injection Moulding Industries, USA). It was suggested t h a t a high metal loading in a MIM feedstock provides a more h o m o g e n e o u s melt but t h e r e are also t e m p e r a t u r e losses in the feeding systems and problems in mould filling. By elimination of the runners the melt may be maintained at t e m p e r a t u r e until it enters the mould cavity. Factors influencing the d e s i g n of r u n n e r l e s s s y s t e m s w e r e discussed. INVESTIGATION OF INJECTION MOULDING FOR PM COMPOUND MATERIALS K. Pischang et al (Dresden University of Technology, Dresden, Germany). The p a p e r p r e s e n t e d the results of a study of Multiple C o m p o n e n t Injection Moulding. This was used to produce a p a r t with a layered structure. Techniques used i n c l u d e d p o w d e r p r e p a r a t i o n by h i g h e n e r g y m i l l i n g , a d d i t i o n of s i n t e r i n g enhancers and variation of powder:binder ratios. D E F E C T FORMATION AND DENSIFICATION MECHANISMS IN INJECTION MOULDED C E M E N T E D CARBIDE M.J. Yang, R.M. German (Pennsylvania State University, Pennsylvania, USA). It was noted t h a t MIM c o m p a c t s may suffer from cracking during processing and t h a t only s o m e can be a t t r i b u t e d to unsuitable process conditions. The need for c l o s e p r o c e s s c o n t r o l a n d a full understanding of the process was
LITERATURE
REVIEW
emphasized. The investigation, which was described, explored debinding and densification m e c h a n i s m s in WC-Co m a d e by MIM. Effects of process conditions were considered. RAPID D E N S I F I C A T I O N OF PARTS TO FULL DENSITY R.V. Raman et al (Ceracon Inc, Scaramento, California, USA). It was r e p o r t e d t h a t MIM had been combined with the Ceracon T M p s e u d o HIP process to make fully d e n s e n e a r net s h a p e superalloy parts. Effects of processing on densities and microstructures and analysis of grain boundary chemistry were described and discussed. IMAGE ACQUISITION AND ANALYSIS DURING SINTERING A S A MEANS OF PROCESS MONITORING D.W. Yeol ( C e n t o r r / V a c u u m I n d u s t r i e s , Somerville, USA). An image capture and analysis system for m o n i t o r i n g t h e h i g h t e m p e r a t u r e s i n t e r i n g of p a r t s w a s o u t l i n e d . The technique was reported to allow q u a n t i f i c a t i o n of p a r t size a n d s h a p e during p r o c e s s i n g and c o r r e l a t i o n with process conditions. The use of the m e t h o d as a real t i m e m e a n s of c o n t r o l w a s discussed. GRAVITY F E E D METAL I N J E C T I O N MOULDING Lawley et al (Drexel University, USA). Use of MIM for p r o d u c t i o n of metal or c e r a m i c p a r t s w a s d i s c u s s e d a n d p r o b l e m s noted. The use of gravity injection, or a system with low injection p r e s s u r e s , was illustrated. E x p e r i m e n t s with steel powders and carbonyl Fe powder, with two different binders, one inert and one reactive relative to the m e t a l p o w d e r , w e r e c a r r i e d out to d e t e r m i n e t h e effects of p a r t i c l e size, p r o c e s s m o d e a n d b i n d e r t y p e on properties and structures. CORROSION T E S T I N G OF METAL INJECTION MOULDED STAINLESS STEEL M. Bulger, A. Erickson (FloMet, USA). A p p l i c a t i o n of i n j e c t i o n m o u l d e d stainless steel parts were discussed with reference to corrosion resistance and the need to test different ways d e p e n d i n g on the structure, austenitic or ferritic, etc. It w a s r e p o r t e d t h a t MIM s t a i n l e s s steel, p r o c e s s e d to h i g h d e n s i t y , h a s good corrosion resistance. Test m e t h o d s were reviewed and proposals for test procedures f o r MIM s t a i n l e s s steels were made. Comparisons were m a d e b e t w e e n MIM a n d w r o u g h t stainless steels.
Composites WEAR RESISTANCE OF A COMPOSITIONALLY GRADED TOOL STEEL R.A_ Queeney, S.F. Gradess (University of Pennsylvania, USA). The improvements in t h e w e a r performance of tool steels by reinforcement with ceramic particles were discussed, the disadvantage being the loss of t e n s i l e a n d b e n d s t r e n g t h . It w a s reported t h a t the use of compositionally g r a d e d or l a m i n a t e d m a t e r i a l s c o u l d o v e r c o m e t h i s d r a w b a c k . A s t u d y of laminated tool steels, made by PM, was described and it was reported t h a t the compressive stresses introduced resulted in e n h a n c e d wear p r o p e r t i e s c o m p a r e d with simple reinforced materials. SURFACE ANALYSIS OF DIAMOND AND IRON BASE MATRIX MATERIALS Y-K. Wu, Y. Qing (Chongquing Non-Ferrous Metals Industry Corp, China). An investigation of surface reactions between d i a m o n d and a Fe base matrix was described. It was reported t h a t the reactions resulted in improved bonding when hot pressed in the range 700 to 870°C. This was a t t r i b u t e d to reduction of surface oxides and the formation of metal carbides. B E N D P R O P E R T I E S OF NICKELALUMINA MICRO-INFILTRATED MACRO-LAMINATED COMPOSITE A_ Bose, J. Lankford ( P a r m a t e c h Corp, Petaluma, California, USA). The d e v e l o p m e n t of a micro-infiltrated macrolaminated Ni-Al203 c o m p o s i t e material was described. The objective was to combine the ductility, but low strength, of the Ni with the high s t r e n g t h but low t o u g h n e s s of t h e Al.~O3. It was anticipated t h a t plastic deformation in the Ni matrix w o u l d a r r e s t c r a c k p r o p a g a t i o n . PM m e t h o d s w e r e u s e d to f a b r i c a t e t h e materials which were t h e n subjected to bend tests. POROUS S I N T E R E D METAL FIBRE PRODUCTS R. De Bruyne (NV Bekaert Sa, Belgium). The use of metal fibres, as small as 1 I~mm in diameter, as a PM raw material was discussed. It was reported t h a t the fibres were available in a range of metals and alloys and can be fabricated alone or in conjunction with metal powders or o t h e r non-metallic fibres. Applications were said to include filter media, surgical prostheses, p r e f o r m s for f u r t h e r p r o c e s s i n g a n d toughened ceramics. Structures were shown to have high porosity and permeability and solid retention capacity.
MPR N o v e m b e r 1994 41
of automotive gears was described. The results of s t u d i e s of bevel gears were p r e s e n t e d . Good c o r r e l a t i o n b e t w e e n p o r o s i t y a n d w e a r c h a r a c t e r i s t i c s was reported. Comparison was made with the same p a r t m a d e by forging.
Metal injection moulding INJECTION MOULDING OF HARDMETALS USING AN POLYACETYL BASED B I N D E R J.S. Ebenhoch, W. Hesse (BASF AG, Ludwigshafen, Germany). P r o b l e m s a r i s i n g in t h e MIM o f h a r d m e t a l s were discussed, the use of a polyacetyl b a s e d b i n d e r a n d c a t a l y t i c debinding, developed for hardmetals, was described. Properties and microstructures of injection moulded WC-Co were p r e s e n t e d and discussed with respect to the influence of f e e d s t o c k c o m p o s i t i o n a n d p r o c e s s variables. R U N N E R L E S S SYSTEMS FOR PROCESSING POLYMERS WITH A HEAVY LOADING OF METAL POWDER D.J. Seres (Injection Moulding Industries, USA). It was suggested t h a t a high metal loading in a MIM feedstock provides a more h o m o g e n e o u s melt but t h e r e are also t e m p e r a t u r e losses in the feeding systems and problems in mould filling. By elimination of the runners the melt may be maintained at t e m p e r a t u r e until it enters the mould cavity. Factors influencing the d e s i g n of r u n n e r l e s s s y s t e m s w e r e discussed. INVESTIGATION OF INJECTION MOULDING FOR PM COMPOUND MATERIALS K. Pischang et al (Dresden University of Technology, Dresden, Germany). The p a p e r p r e s e n t e d the results of a study of Multiple C o m p o n e n t Injection Moulding. This was used to produce a p a r t with a layered structure. Techniques used i n c l u d e d p o w d e r p r e p a r a t i o n by h i g h e n e r g y m i l l i n g , a d d i t i o n of s i n t e r i n g enhancers and variation of powder:binder ratios. D E F E C T FORMATION AND DENSIFICATION MECHANISMS IN INJECTION MOULDED C E M E N T E D CARBIDE M.J. Yang, R.M. German (Pennsylvania State University, Pennsylvania, USA). It was noted t h a t MIM c o m p a c t s may suffer from cracking during processing and t h a t only s o m e can be a t t r i b u t e d to unsuitable process conditions. The need for c l o s e p r o c e s s c o n t r o l a n d a full understanding of the process was
LITERATURE
REVIEW
emphasized. The investigation, which was described, explored debinding and densification m e c h a n i s m s in WC-Co m a d e by MIM. Effects of process conditions were considered. RAPID D E N S I F I C A T I O N OF PARTS TO FULL DENSITY R.V. Raman et al (Ceracon Inc, Scaramento, California, USA). It was r e p o r t e d t h a t MIM had been combined with the Ceracon T M p s e u d o HIP process to make fully d e n s e n e a r net s h a p e superalloy parts. Effects of processing on densities and microstructures and analysis of grain boundary chemistry were described and discussed. IMAGE ACQUISITION AND ANALYSIS DURING SINTERING A S A MEANS OF PROCESS MONITORING D.W. Yeol ( C e n t o r r / V a c u u m I n d u s t r i e s , Somerville, USA). An image capture and analysis system for m o n i t o r i n g t h e h i g h t e m p e r a t u r e s i n t e r i n g of p a r t s w a s o u t l i n e d . The technique was reported to allow q u a n t i f i c a t i o n of p a r t size a n d s h a p e during p r o c e s s i n g and c o r r e l a t i o n with process conditions. The use of the m e t h o d as a real t i m e m e a n s of c o n t r o l w a s discussed. GRAVITY F E E D METAL I N J E C T I O N MOULDING Lawley et al (Drexel University, USA). Use of MIM for p r o d u c t i o n of metal or c e r a m i c p a r t s w a s d i s c u s s e d a n d p r o b l e m s noted. The use of gravity injection, or a system with low injection p r e s s u r e s , was illustrated. E x p e r i m e n t s with steel powders and carbonyl Fe powder, with two different binders, one inert and one reactive relative to the m e t a l p o w d e r , w e r e c a r r i e d out to d e t e r m i n e t h e effects of p a r t i c l e size, p r o c e s s m o d e a n d b i n d e r t y p e on properties and structures. CORROSION T E S T I N G OF METAL INJECTION MOULDED STAINLESS STEEL M. Bulger, A. Erickson (FloMet, USA). A p p l i c a t i o n of i n j e c t i o n m o u l d e d stainless steel parts were discussed with reference to corrosion resistance and the need to test different ways d e p e n d i n g on the structure, austenitic or ferritic, etc. It w a s r e p o r t e d t h a t MIM s t a i n l e s s steel, p r o c e s s e d to h i g h d e n s i t y , h a s good corrosion resistance. Test m e t h o d s were reviewed and proposals for test procedures f o r MIM s t a i n l e s s steels were made. Comparisons were m a d e b e t w e e n MIM a n d w r o u g h t stainless steels.
Composites WEAR RESISTANCE OF A COMPOSITIONALLY GRADED TOOL STEEL R.A_ Queeney, S.F. Gradess (University of Pennsylvania, USA). The improvements in t h e w e a r performance of tool steels by reinforcement with ceramic particles were discussed, the disadvantage being the loss of t e n s i l e a n d b e n d s t r e n g t h . It w a s reported t h a t the use of compositionally g r a d e d or l a m i n a t e d m a t e r i a l s c o u l d o v e r c o m e t h i s d r a w b a c k . A s t u d y of laminated tool steels, made by PM, was described and it was reported t h a t the compressive stresses introduced resulted in e n h a n c e d wear p r o p e r t i e s c o m p a r e d with simple reinforced materials. SURFACE ANALYSIS OF DIAMOND AND IRON BASE MATRIX MATERIALS Y-K. Wu, Y. Qing (Chongquing Non-Ferrous Metals Industry Corp, China). An investigation of surface reactions between d i a m o n d and a Fe base matrix was described. It was reported t h a t the reactions resulted in improved bonding when hot pressed in the range 700 to 870°C. This was a t t r i b u t e d to reduction of surface oxides and the formation of metal carbides. B E N D P R O P E R T I E S OF NICKELALUMINA MICRO-INFILTRATED MACRO-LAMINATED COMPOSITE A_ Bose, J. Lankford ( P a r m a t e c h Corp, Petaluma, California, USA). The d e v e l o p m e n t of a micro-infiltrated macrolaminated Ni-Al203 c o m p o s i t e material was described. The objective was to combine the ductility, but low strength, of the Ni with the high s t r e n g t h but low t o u g h n e s s of t h e Al.~O3. It was anticipated t h a t plastic deformation in the Ni matrix w o u l d a r r e s t c r a c k p r o p a g a t i o n . PM m e t h o d s w e r e u s e d to f a b r i c a t e t h e materials which were t h e n subjected to bend tests. POROUS S I N T E R E D METAL FIBRE PRODUCTS R. De Bruyne (NV Bekaert Sa, Belgium). The use of metal fibres, as small as 1 I~mm in diameter, as a PM raw material was discussed. It was reported t h a t the fibres were available in a range of metals and alloys and can be fabricated alone or in conjunction with metal powders or o t h e r non-metallic fibres. Applications were said to include filter media, surgical prostheses, p r e f o r m s for f u r t h e r p r o c e s s i n g a n d toughened ceramics. Structures were shown to have high porosity and permeability and solid retention capacity.
MPR N o v e m b e r 1994 41