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Microscopial behaviour of elemental additives in hot pressed silicon carbide
EFFECT OF SINTERING ATMOSPHERE ON T H E P R O P E R T I E S OF C E R M E T S
inclusions if Si c o m p o u n d s a n d h a d a h i g h wear resistance.
NANO-STRUCTURE O F MACHINABLE SILICON CARBIDE
P. E t t m a y e r et al, (Technical Univ of Vienna, Austria). Powder Metall. Int., Vol 23, No 4, 1991, 224-230. The effects of sintering a t m o s p h e r e on t h e c u t t i n g p r o p e r t i e s of c e m e n t s was studied. Processing of m i x e d c a r b i d e s / n i t r i d e s a n d c a r b o n i t r i d e s is discussed. The role of N a n d O c o n t e n t s in s t a r t i n g and finished m a t e r i a l is considered. The sintering atmosphere is s h o w n t o significantly affect t h e b i n d e r element.
STRUCTURE F O R M A T I O N IN H I G H T E M P E R A T U R E T R E A T M E N T OF NICKEL C E M E N T E D T U N G S T E N CARBIDE
K.Suganuma et al. J. Japan Soc. Powder a n d Powder Metallurgy, Vol 38, No 3, 1991, 374-377. (In J a p a n e s e ) . Fine ~si powder was m o u l d e d w i t h a polymer additive and sintered. The s t r u c t u r e a n d mechanical p r o p e r t i e s of t h e m a t e r i a l were evaluated a n d was found to retain strength at temperatures up o 1500°C. Decomposition of t h e polymer was fond to leave a fine r i b b o n like network of C in t h e s t r u c t u r e a n d t h e m a c h i n a b i l i t y of t h e m a t e r i a l is a t t r i b u t e d to this. It is suggested t h a t t h e m a t e r i a l will find high t e m p e r a t u r e applications.
E F F E C T S O F H I G H P R E S S U R E S ON THE STRUCTURE OF POLYCRYSTALLINE A L U M I N I U M NITRIDE A.N.
Pilyankevich
et
A~F. Lisovsky, (Ukraine Academy of Sciences, Kiev, USSR). Powder Metallurgy Science and Technology, Vol 2, No 3, 1991, 43-51. Interactions, during liquid phase sintering, of WC c e m e n t e d with pure Ni or a Ni-base alloy have been investigated. It is r e p o r t e d t h a t t h e Ni base liquid p h a s e a b s o r b s material from h e carbide resulting in s t r u c t u r a l changes. The p r o d u c t i o n of Ni and Ni base c e m e n t e d WC alloys w i t h p r o p e r t i e s similar to those of WC-Co was demonstrated.
al.
PoroshkovayaMetallurgiya, No 3, 1991, 38-44, (In Russian). Structural transformations occurring during t h e sintering, a t high pressures, 100 M P a a n d t e m p e r a t u r e s , 1700 t o 2000°C, of wustite AIN were investigated by electron microscopy. AIN was k n o w n to undergo plastic deformation, recrystalline, r e c r y s t a l l i z a t i o n a n d t h e f o r m a t i o n of micropores in t h e grain boundaries. The f o r m a t i o n of s p h a l e r i t e was n o t detected and this is a t t r i b u t e d to high stacking fault energies. Cubic a l u m i n i u m oxynitride was also f o u n d a t h i g h t e m p e r a t u r e a n d pressures.
MICROSCOPIAL BEHAVIOUR OF E L E M E N T A L A D D I T I V E S IN HOT P R E S S E D SILICON CARBIDE
D E P E N D E N C E OF P R O P E R T I E S OF NICKEL BORIDE MATERIALS ON DISPERSIVITY OF GLASS B I N D E R
I N F L U E N C E OF STRUCTURAL D E F E C T S IN COBALT-CEMENTED T U N G S T E N CARBIDE ON IMPACT P R O P E R T I E S OF THE ALLOY
Y.G. G r e b e n k i n a et al, Poroshkovaya Metallurgiya, No 3, 1991, 4-46. (In Russian). The use of a Pb glass b i n d e r in NiB was investigated. It was shown t h a t w h e n t h e b i n d e r h a s a dispersivity of 1 to 2 ~ m t h e lowest specific surface is found. Thermal t r e a t m e n t of t h e m a t e r i a l was optimized. P R O P E R T I E S OF I R O N / S I L I C O N NITRIDE C O M P O S I T E COATINGS T.N. Miller et al. Poroshkovaya Metallurgiya, No 3, 1991, 65-68. (In Russian). Composite coatings consisting of Fe a n d SiNe were applied to a s u b s t a t e by a p l a s m a technique. The coatings were found to be a m e t a l l i c m a t r i x w i t h i n c l u s i o n if Si compounds sand had a high wear resistance. P R O P E R T I E S OF I R O N / S I L I C O N NITRIDE C O M P O S I T E COATINGS T.N. Miller et al, Poroshkovaya Metallurgiya, No 3, 1991, 65-68. (In Russian). Composite coatings consisting of Fe and SiN2 were applied to a s u b s t r a t e by a p l a s m a t e c h n i q u e . The c o a t i n g s w e r e f o u n d to b e a m e t a l l i c m a t r i x w i t h
H. H a n q u a n et al. (Inst of Metal Research, Shenyang, China). PM Technology, Vol 9, No 2, 1991, 70-77. (In Chinese). The use of electron microscopy for t h e e x a m i n a t i o n of SiC doped w i t h B, A1 or C is described. New p h a s e s are r e p o r t e d in h o t pressed materials depending on c o m p o s i t i o n . E f f e c t s of s i n t e r i n g o n properties are discussed.
R. Qiufeng et al. (Central I r o n a n d Steel Inst, China). PM Technology, Vol 9, No 2, 1991, 78-82. (In Chinese). An empirical relationship is established between impact toughness and impact t r a n s v e r s e r u p t u r e s t r e n g t h for WC-Co alloys. Use of HIP was shown to increase constancy of properties. E F F E C T OF SPARK D I S C H A R G E WIRE CUTTING ON THE MICROSTRUCTURE OF COBALT-CEMENTED T U N G S T E N CARBIDE L.Shourong, (Tianjin Inst of Hard Alloys, Chian). PM Technology, Vol 9, No 2, 1991, 83-89. (In Chinese). S u r f a c e s o f WC-Co c u t b y s p a r k discharge wire cutting have been e x a m i n e d to d e t e r m i n e t h e e x t e n t of structural changes b r o u g h t a b o u t by t h e cutting process. No oxidation or c h a n g e of composition were found. Surface cavities containing eroded particles were n o t e d in t h e m e l t e d surface layer as were d e e p e r structural alterations. There was a r e d u c t i o n in mechanical properties to a d e p t h of 70 to 100pm.
MECHANICAL P R O P E R T I E S OF SINGLE A N D TWO P H A S E SILICON CARBIDE-ALUMINIUM N I T R I D E ALLOYS J-F. Li et al, J. Japan Soc. Powder a n d Powder Metallurgy, Vol 38, No 3, 1991, 390-394. (In J a p a n e s e ) . The paper describes experiments designed to improve the mechanical p r o p e r t i e s of SiC by alloying w i t h up to 20mo%A1N. Specimens were fabricated by HIP of reaction synthesized solid solution material. The solid solution alloys were found to have s t r e n g t h s u p to 1000 MPa a t 5%A1N w i t h i n c r e a s e d fracture toughness. In t h e two p h a s e alloys t h e p r e s e n c e of A1N particles increases s t r e n g t h and fracture t o u g h n e s s more effectively. SWELLING OF THE SURFACE O F A SOLID I N D U C E D BY ION IMPLANTATION M. Ikeyama et al. J. Japan Soc, Powder a n d Powder Metallurgy, Vol 38, No 3, 1991, 411-414. (In J a p a n e s e ) . Surface swelling of SiN a n d A1203 w h i c h h a d been subjected to N, Si a n d Ni ion b o m b a r d m e n t was m e a s u r e d as a function of ion dose. S a t u r a t i o n of t h e surface was found to occur. For heavier ions a n d lower t e m p e r a t u r e s t h e a m o u n t of swelling a t s a t u r a t i o n was found to be greater.
Intermetallic materials MECHANICAL A N D PHYSICAL P R O P E R T I E S OF POROUS TITANIUM NICKELIDE V.V. Skorokhod a n d S.M. Solonin, Poroshkovaya Metallurgiya, No 3, 1991, 34-38. (In Russian). The effects of p r o c e s s v a r i a b l e s o n mechanical a n d physical properties of TiNi are described t o g e t h e r with t h e effects of porosity and the characteristics the interparticle contact zones. The quality of t h e interparticle contact is k n o w n to affect t h e properties in t h e porosity r a n g e 30 to 40%. D e f o r m a t i o n c h a r a c t e r i s t i c s a n d a m a r t e n s i t i c t r a n s f o r m a t i o n are discussed.
MPR November 1991 55
inclusions if Si c o m p o u n d s a n d h a d a h i g h wear resistance.
NANO-STRUCTURE O F MACHINABLE SILICON CARBIDE
P. E t t m a y e r et al, (Technical Univ of Vienna, Austria). Powder Metall. Int., Vol 23, No 4, 1991, 224-230. The effects of sintering a t m o s p h e r e on t h e c u t t i n g p r o p e r t i e s of c e m e n t s was studied. Processing of m i x e d c a r b i d e s / n i t r i d e s a n d c a r b o n i t r i d e s is discussed. The role of N a n d O c o n t e n t s in s t a r t i n g and finished m a t e r i a l is considered. The sintering atmosphere is s h o w n t o significantly affect t h e b i n d e r element.
STRUCTURE F O R M A T I O N IN H I G H T E M P E R A T U R E T R E A T M E N T OF NICKEL C E M E N T E D T U N G S T E N CARBIDE
K.Suganuma et al. J. Japan Soc. Powder a n d Powder Metallurgy, Vol 38, No 3, 1991, 374-377. (In J a p a n e s e ) . Fine ~si powder was m o u l d e d w i t h a polymer additive and sintered. The s t r u c t u r e a n d mechanical p r o p e r t i e s of t h e m a t e r i a l were evaluated a n d was found to retain strength at temperatures up o 1500°C. Decomposition of t h e polymer was fond to leave a fine r i b b o n like network of C in t h e s t r u c t u r e a n d t h e m a c h i n a b i l i t y of t h e m a t e r i a l is a t t r i b u t e d to this. It is suggested t h a t t h e m a t e r i a l will find high t e m p e r a t u r e applications.
E F F E C T S O F H I G H P R E S S U R E S ON THE STRUCTURE OF POLYCRYSTALLINE A L U M I N I U M NITRIDE A.N.
Pilyankevich
et
A~F. Lisovsky, (Ukraine Academy of Sciences, Kiev, USSR). Powder Metallurgy Science and Technology, Vol 2, No 3, 1991, 43-51. Interactions, during liquid phase sintering, of WC c e m e n t e d with pure Ni or a Ni-base alloy have been investigated. It is r e p o r t e d t h a t t h e Ni base liquid p h a s e a b s o r b s material from h e carbide resulting in s t r u c t u r a l changes. The p r o d u c t i o n of Ni and Ni base c e m e n t e d WC alloys w i t h p r o p e r t i e s similar to those of WC-Co was demonstrated.
al.
PoroshkovayaMetallurgiya, No 3, 1991, 38-44, (In Russian). Structural transformations occurring during t h e sintering, a t high pressures, 100 M P a a n d t e m p e r a t u r e s , 1700 t o 2000°C, of wustite AIN were investigated by electron microscopy. AIN was k n o w n to undergo plastic deformation, recrystalline, r e c r y s t a l l i z a t i o n a n d t h e f o r m a t i o n of micropores in t h e grain boundaries. The f o r m a t i o n of s p h a l e r i t e was n o t detected and this is a t t r i b u t e d to high stacking fault energies. Cubic a l u m i n i u m oxynitride was also f o u n d a t h i g h t e m p e r a t u r e a n d pressures.
MICROSCOPIAL BEHAVIOUR OF E L E M E N T A L A D D I T I V E S IN HOT P R E S S E D SILICON CARBIDE
D E P E N D E N C E OF P R O P E R T I E S OF NICKEL BORIDE MATERIALS ON DISPERSIVITY OF GLASS B I N D E R
I N F L U E N C E OF STRUCTURAL D E F E C T S IN COBALT-CEMENTED T U N G S T E N CARBIDE ON IMPACT P R O P E R T I E S OF THE ALLOY
Y.G. G r e b e n k i n a et al, Poroshkovaya Metallurgiya, No 3, 1991, 4-46. (In Russian). The use of a Pb glass b i n d e r in NiB was investigated. It was shown t h a t w h e n t h e b i n d e r h a s a dispersivity of 1 to 2 ~ m t h e lowest specific surface is found. Thermal t r e a t m e n t of t h e m a t e r i a l was optimized. P R O P E R T I E S OF I R O N / S I L I C O N NITRIDE C O M P O S I T E COATINGS T.N. Miller et al. Poroshkovaya Metallurgiya, No 3, 1991, 65-68. (In Russian). Composite coatings consisting of Fe a n d SiNe were applied to a s u b s t a t e by a p l a s m a technique. The coatings were found to be a m e t a l l i c m a t r i x w i t h i n c l u s i o n if Si compounds sand had a high wear resistance. P R O P E R T I E S OF I R O N / S I L I C O N NITRIDE C O M P O S I T E COATINGS T.N. Miller et al, Poroshkovaya Metallurgiya, No 3, 1991, 65-68. (In Russian). Composite coatings consisting of Fe and SiN2 were applied to a s u b s t r a t e by a p l a s m a t e c h n i q u e . The c o a t i n g s w e r e f o u n d to b e a m e t a l l i c m a t r i x w i t h
H. H a n q u a n et al. (Inst of Metal Research, Shenyang, China). PM Technology, Vol 9, No 2, 1991, 70-77. (In Chinese). The use of electron microscopy for t h e e x a m i n a t i o n of SiC doped w i t h B, A1 or C is described. New p h a s e s are r e p o r t e d in h o t pressed materials depending on c o m p o s i t i o n . E f f e c t s of s i n t e r i n g o n properties are discussed.
R. Qiufeng et al. (Central I r o n a n d Steel Inst, China). PM Technology, Vol 9, No 2, 1991, 78-82. (In Chinese). An empirical relationship is established between impact toughness and impact t r a n s v e r s e r u p t u r e s t r e n g t h for WC-Co alloys. Use of HIP was shown to increase constancy of properties. E F F E C T OF SPARK D I S C H A R G E WIRE CUTTING ON THE MICROSTRUCTURE OF COBALT-CEMENTED T U N G S T E N CARBIDE L.Shourong, (Tianjin Inst of Hard Alloys, Chian). PM Technology, Vol 9, No 2, 1991, 83-89. (In Chinese). S u r f a c e s o f WC-Co c u t b y s p a r k discharge wire cutting have been e x a m i n e d to d e t e r m i n e t h e e x t e n t of structural changes b r o u g h t a b o u t by t h e cutting process. No oxidation or c h a n g e of composition were found. Surface cavities containing eroded particles were n o t e d in t h e m e l t e d surface layer as were d e e p e r structural alterations. There was a r e d u c t i o n in mechanical properties to a d e p t h of 70 to 100pm.
MECHANICAL P R O P E R T I E S OF SINGLE A N D TWO P H A S E SILICON CARBIDE-ALUMINIUM N I T R I D E ALLOYS J-F. Li et al, J. Japan Soc. Powder a n d Powder Metallurgy, Vol 38, No 3, 1991, 390-394. (In J a p a n e s e ) . The paper describes experiments designed to improve the mechanical p r o p e r t i e s of SiC by alloying w i t h up to 20mo%A1N. Specimens were fabricated by HIP of reaction synthesized solid solution material. The solid solution alloys were found to have s t r e n g t h s u p to 1000 MPa a t 5%A1N w i t h i n c r e a s e d fracture toughness. In t h e two p h a s e alloys t h e p r e s e n c e of A1N particles increases s t r e n g t h and fracture t o u g h n e s s more effectively. SWELLING OF THE SURFACE O F A SOLID I N D U C E D BY ION IMPLANTATION M. Ikeyama et al. J. Japan Soc, Powder a n d Powder Metallurgy, Vol 38, No 3, 1991, 411-414. (In J a p a n e s e ) . Surface swelling of SiN a n d A1203 w h i c h h a d been subjected to N, Si a n d Ni ion b o m b a r d m e n t was m e a s u r e d as a function of ion dose. S a t u r a t i o n of t h e surface was found to occur. For heavier ions a n d lower t e m p e r a t u r e s t h e a m o u n t of swelling a t s a t u r a t i o n was found to be greater.
Intermetallic materials MECHANICAL A N D PHYSICAL P R O P E R T I E S OF POROUS TITANIUM NICKELIDE V.V. Skorokhod a n d S.M. Solonin, Poroshkovaya Metallurgiya, No 3, 1991, 34-38. (In Russian). The effects of p r o c e s s v a r i a b l e s o n mechanical a n d physical properties of TiNi are described t o g e t h e r with t h e effects of porosity and the characteristics the interparticle contact zones. The quality of t h e interparticle contact is k n o w n to affect t h e properties in t h e porosity r a n g e 30 to 40%. D e f o r m a t i o n c h a r a c t e r i s t i c s a n d a m a r t e n s i t i c t r a n s f o r m a t i o n are discussed.
MPR November 1991 55