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Mechanical properties and wear behaviour of diluted high speed steels
studied. Wear resistance and cutting p e r f o r m a n c e of PM HIP M2 steel were reported to increase with %V. Correlations between austenitic grain size, V c o n t e n t a n d wear and cutting performance were discussed. MECHANICAL P R O P E R T I E S A N D WEAR BEHAVIOUR OF DILUTED HIGH S P E E D S T E E L S
J.M. Torralba et al (Polytechnical University of Madrid, Madrid, Spain). A study aimed at improving the c o m p r e s s i b i l i t y of HSS p o w d e r s w a s described. HSS powder was diluted with a prealloyed Fe powder, sintering being in a N/H mixture. The results of m i c r o s t r u c t u r a l e x a m i n a t i o n were discussed. S I N T E R I N G OF MIXED POWDERS FOR WEAR APPLICATIONS J.V. Wood et al (University of Nottingham, Nottingham, UK). Press-and-sinter technology was discussed with respect to the m a n u f a c t u r e of automotive components. It was shown t h a t Fe a n d low alloy steels often have i n a d e q u a t e wear resistance. Additions of HSS powders to improve wear properties was reported. The c u r r e n t state of this development and test results were discussed.
D E S I G N OF NEW FERROUS VALVE SEAT AND VALVE GUIDE MATERIALS
H.)~Brownlie et al (Brico Engineering Ltd, Coventry, UK). The properties of the materials used a n d t h e design of valve seats a n d guides were reviewed with respect to modelling, s i m u l a t i o n testing, h e a t transfer, stress a n d m a c h i n a b i l i t y . The role of PM in making valve seats and guides was discussed, raw materials and quality control b e i n g c o n s i d e r e d t o g e t h e r w i t h v a l v e t r a i n t r i b o l o g y a n d c o n t r o l of emissions. HEAT AND WEAR RESISTANT F E R R O U S PM MATERIALS FOR HIGH PERFORMANCE E N G I N E S Fujiki et al (Nissan Motor Co, Tokyo, Japan). Severe wear and oxidation of c o m p o n e n t s in high performance internal c o m b u s t i o n engines were discussed a n d ways of r e d u c i n g t h e m o u t l i n e d . New f e r r o u s PM m a t e r i a l s w e r e r e p o r t e d including a v a c u u m sintered Mo alloy steel for intake valve seats, a Co steel containing h a r d particles for e x h a u s t valve seats, a CrCu steel containing solid p h a s e lubricants for valve guides a n d a n austenitic stainless steel for t u r b o c h a r g e r parts.
54 MPR December 1993
COMPOSITION CHANGE BY LIQUID FILM MIGRATION IN A S I N T E R E D IRON ALLOY FOR CAMSHAFTS
H.S. Shin et al (Korea Advanced Inst of Science a n d Techynology, Korea). It was r e p o r t e d t h a t w h e n Fe-5%Crl%Mo-2%Cu-O.5%P with a d d e d C is liquid p h a s e sintered at 1120°C t h e liquid p h a s e migrates during cooling a n d leaves a solid solution enriched in C, Mo, Cu a n d P b u t depleted of Cr. The driving force for t h e migration was a t t r i b u t e d to differences in coherency energy. The properties of t h e alloy, which was to be used as a camshaft, w e r e a t t r i b u t e d to t h e c o m p o s i t i o n a l changes.
Self propogation reaction sintering ANALYSIS A N D OBSERVATIONS OF SELF PROPAGATING C O M B U S T I O N SYNTHESIS Z.& Munir (Univeristy of California, Davis, California, USA). R e s e a r c h o n self p r o p a g a t i n g h i g h t e m p e r a t u r e synthesis was described a n d d i s c u s s e d in t h e light of e x p e r i m e n t a l results concerning synthesis of carbides a n d b o r i d e s . It w a s s h o w n t h a t t h e formation of dense bodies requires application of external forces to counteract pore formation. Porosity generation was analysed with regard to intrinsic a n d extrinsic contributions.
SELF PROPAGATING REACTION S I N T E R I N G OF INTERMETALLIC COMPOUNDS
Y. Kaidea ( N a t i o n a l R e s e a r c h I n s t for Metals, Tokyo, J a p a n ) . Self p r o p a g a t i n g reaction sintering was discussed with reference to application to synthesis of intermetallic c o m p o u n d s a n d ceramics. A detailed account of p r o d u c t i o n of TiNi s h a p e m e m o r y alloy a n d TiA1 was presented.
Some of t h e powders were spray deposited to evaluate wear resistance. D E N S I F I C A T I O N OF A CERAMIC LINER IN A S T E E L TUBE BY CENTRIFUGAL FORCES A N D SELF PROPAGATING HIGH T E M P E R A T U R E REACTION SYNTHESIS Y. Sheng et al (Univeristy of Science a n d Technology, Beijing, China). T h e u s e of r e a c t i o n s y n t h e s i s a n d centrifugal forces to line a steel pipe with a ceramic m a t e r i a l was described. The c e n t r i f u g a l forces aid t h e r e m o v a l of gaseous reaction p r o d u c t s a n d decrease t h e porosity of t h e lining. Material based on Fe a n d A1 oxides a n d feldspars were used a n d t h e linings were shown to form spinels during processing.
REACTIVE SYNTHESIS OF GAMMATITANNIUM ALUMINIDE
M. Dahms, G-X. Wang (GKSS Research Centre, Geesthacht, Germany). The f o r m a t i o n of TiA1 from heavily d e f o r m e d Ti-A1 p o w d e r m i x t u r e s was described. TiA1 a n d TiaA1 form during self p r o p o g a t i n g high t e m p e r a t u r e synthesis, pressure being required to close porosity. E x t r u s i o n a n d HIP were used to produce dense materials. Repeated extrusion a n d cold rolling could be used to refine t h e microstructure. P R O C E S S I N G D E S I G N FOR SHOCK WAVE REACTIVE SYNTHESIS OF INTERMETALLIC MATERIALS T. Aizawa (University of Tokyo, Tokyo, Japan). The use of shock wave reaction synthesis for t h e producion of synthetic d i a m o n d a n d cubic BN h a r d m a t e r i a l was discussed. Theoretical studies were used to evaluate t h e design of a cell of shock r e a c t i o n synthesis a n d to estimate t h e time a n d temperatures required. Various metal a l u m i n i d e s were u s e d to e v a l u a t e t h e m e c h a n i s m s of s h o c k w a v e r e a c t i v e synthesis.
SYNTHESIS OF INTERMETALLIC C O M P O U N D MATRIX C O M P O S I T E S BY REACTION SYNTHESIS
SHOCK WAVE P R O C E S S I N G OF NONEQUILIBRIUM TITANIUM A L U M I N I D E S
R. Knight et al (Drexel University, Philadelphia, Pennsylvania, USA). It was r e p o r t e d t h a t a n u m b e r of intermetallic c o m p o u n d s a n d intermetallic m a t r i x composites, including TiC-NiCr, TiCTiA1, TiC-FeA1, TiC-NiAI, a n d TiC-NiTi, h a d b e e n p r o d u c e d by h i g h t e m p e r a t u r e reaction synthesis for elemental powder mixtures by ignition and chemical synthesis. The powders were characterized a n d were found to contain u p to 60vo1% TiC.
T. Aizawa et al (Univeristy of Tokyo, Tokyo, Japan). Explosive powder processing was r e p o r t e d to h a v e b e e n u s e d in t h e synthesis of Ti aluminides. A n u m b e r of non-equilibrium p h a s e s were shown to be formed and the microstructures and properties were c o m p a r e d with those of conventionally p r o d u c e d Ti aluminides. The m e c h a n i s m s were discussed in the light of t h e design of a variable shock wave reaction system.
J.M. Torralba et al (Polytechnical University of Madrid, Madrid, Spain). A study aimed at improving the c o m p r e s s i b i l i t y of HSS p o w d e r s w a s described. HSS powder was diluted with a prealloyed Fe powder, sintering being in a N/H mixture. The results of m i c r o s t r u c t u r a l e x a m i n a t i o n were discussed. S I N T E R I N G OF MIXED POWDERS FOR WEAR APPLICATIONS J.V. Wood et al (University of Nottingham, Nottingham, UK). Press-and-sinter technology was discussed with respect to the m a n u f a c t u r e of automotive components. It was shown t h a t Fe a n d low alloy steels often have i n a d e q u a t e wear resistance. Additions of HSS powders to improve wear properties was reported. The c u r r e n t state of this development and test results were discussed.
D E S I G N OF NEW FERROUS VALVE SEAT AND VALVE GUIDE MATERIALS
H.)~Brownlie et al (Brico Engineering Ltd, Coventry, UK). The properties of the materials used a n d t h e design of valve seats a n d guides were reviewed with respect to modelling, s i m u l a t i o n testing, h e a t transfer, stress a n d m a c h i n a b i l i t y . The role of PM in making valve seats and guides was discussed, raw materials and quality control b e i n g c o n s i d e r e d t o g e t h e r w i t h v a l v e t r a i n t r i b o l o g y a n d c o n t r o l of emissions. HEAT AND WEAR RESISTANT F E R R O U S PM MATERIALS FOR HIGH PERFORMANCE E N G I N E S Fujiki et al (Nissan Motor Co, Tokyo, Japan). Severe wear and oxidation of c o m p o n e n t s in high performance internal c o m b u s t i o n engines were discussed a n d ways of r e d u c i n g t h e m o u t l i n e d . New f e r r o u s PM m a t e r i a l s w e r e r e p o r t e d including a v a c u u m sintered Mo alloy steel for intake valve seats, a Co steel containing h a r d particles for e x h a u s t valve seats, a CrCu steel containing solid p h a s e lubricants for valve guides a n d a n austenitic stainless steel for t u r b o c h a r g e r parts.
54 MPR December 1993
COMPOSITION CHANGE BY LIQUID FILM MIGRATION IN A S I N T E R E D IRON ALLOY FOR CAMSHAFTS
H.S. Shin et al (Korea Advanced Inst of Science a n d Techynology, Korea). It was r e p o r t e d t h a t w h e n Fe-5%Crl%Mo-2%Cu-O.5%P with a d d e d C is liquid p h a s e sintered at 1120°C t h e liquid p h a s e migrates during cooling a n d leaves a solid solution enriched in C, Mo, Cu a n d P b u t depleted of Cr. The driving force for t h e migration was a t t r i b u t e d to differences in coherency energy. The properties of t h e alloy, which was to be used as a camshaft, w e r e a t t r i b u t e d to t h e c o m p o s i t i o n a l changes.
Self propogation reaction sintering ANALYSIS A N D OBSERVATIONS OF SELF PROPAGATING C O M B U S T I O N SYNTHESIS Z.& Munir (Univeristy of California, Davis, California, USA). R e s e a r c h o n self p r o p a g a t i n g h i g h t e m p e r a t u r e synthesis was described a n d d i s c u s s e d in t h e light of e x p e r i m e n t a l results concerning synthesis of carbides a n d b o r i d e s . It w a s s h o w n t h a t t h e formation of dense bodies requires application of external forces to counteract pore formation. Porosity generation was analysed with regard to intrinsic a n d extrinsic contributions.
SELF PROPAGATING REACTION S I N T E R I N G OF INTERMETALLIC COMPOUNDS
Y. Kaidea ( N a t i o n a l R e s e a r c h I n s t for Metals, Tokyo, J a p a n ) . Self p r o p a g a t i n g reaction sintering was discussed with reference to application to synthesis of intermetallic c o m p o u n d s a n d ceramics. A detailed account of p r o d u c t i o n of TiNi s h a p e m e m o r y alloy a n d TiA1 was presented.
Some of t h e powders were spray deposited to evaluate wear resistance. D E N S I F I C A T I O N OF A CERAMIC LINER IN A S T E E L TUBE BY CENTRIFUGAL FORCES A N D SELF PROPAGATING HIGH T E M P E R A T U R E REACTION SYNTHESIS Y. Sheng et al (Univeristy of Science a n d Technology, Beijing, China). T h e u s e of r e a c t i o n s y n t h e s i s a n d centrifugal forces to line a steel pipe with a ceramic m a t e r i a l was described. The c e n t r i f u g a l forces aid t h e r e m o v a l of gaseous reaction p r o d u c t s a n d decrease t h e porosity of t h e lining. Material based on Fe a n d A1 oxides a n d feldspars were used a n d t h e linings were shown to form spinels during processing.
REACTIVE SYNTHESIS OF GAMMATITANNIUM ALUMINIDE
M. Dahms, G-X. Wang (GKSS Research Centre, Geesthacht, Germany). The f o r m a t i o n of TiA1 from heavily d e f o r m e d Ti-A1 p o w d e r m i x t u r e s was described. TiA1 a n d TiaA1 form during self p r o p o g a t i n g high t e m p e r a t u r e synthesis, pressure being required to close porosity. E x t r u s i o n a n d HIP were used to produce dense materials. Repeated extrusion a n d cold rolling could be used to refine t h e microstructure. P R O C E S S I N G D E S I G N FOR SHOCK WAVE REACTIVE SYNTHESIS OF INTERMETALLIC MATERIALS T. Aizawa (University of Tokyo, Tokyo, Japan). The use of shock wave reaction synthesis for t h e producion of synthetic d i a m o n d a n d cubic BN h a r d m a t e r i a l was discussed. Theoretical studies were used to evaluate t h e design of a cell of shock r e a c t i o n synthesis a n d to estimate t h e time a n d temperatures required. Various metal a l u m i n i d e s were u s e d to e v a l u a t e t h e m e c h a n i s m s of s h o c k w a v e r e a c t i v e synthesis.
SYNTHESIS OF INTERMETALLIC C O M P O U N D MATRIX C O M P O S I T E S BY REACTION SYNTHESIS
SHOCK WAVE P R O C E S S I N G OF NONEQUILIBRIUM TITANIUM A L U M I N I D E S
R. Knight et al (Drexel University, Philadelphia, Pennsylvania, USA). It was r e p o r t e d t h a t a n u m b e r of intermetallic c o m p o u n d s a n d intermetallic m a t r i x composites, including TiC-NiCr, TiCTiA1, TiC-FeA1, TiC-NiAI, a n d TiC-NiTi, h a d b e e n p r o d u c e d by h i g h t e m p e r a t u r e reaction synthesis for elemental powder mixtures by ignition and chemical synthesis. The powders were characterized a n d were found to contain u p to 60vo1% TiC.
T. Aizawa et al (Univeristy of Tokyo, Tokyo, Japan). Explosive powder processing was r e p o r t e d to h a v e b e e n u s e d in t h e synthesis of Ti aluminides. A n u m b e r of non-equilibrium p h a s e s were shown to be formed and the microstructures and properties were c o m p a r e d with those of conventionally p r o d u c e d Ti aluminides. The m e c h a n i s m s were discussed in the light of t h e design of a variable shock wave reaction system.