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Dawn of the hardmetal age
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SIMULATION OF LASER Q U E N C H I N G TO A S S E S S THERMOPHYSICAL P R O P E R T I E S OF TITANIUM CARBIDE
P~ B~chli a n d A. Batter, (University of Berne, Berne, Switzerland), Int J Refractory Metals & Hard Materials, Vol 11, No 2, 1992, 113-119. Nanosecond laser q u e n c h i n g of TIC was e x a m i n e d by c o m p u t e r s i m u l a t i o n a n d experiment. The model allows e x a m i n a t i o n of laser induced melting a n d crystallization on cooling. By c o m p a r i s o n of the model predictions and the e x p e r i m e n t a l results it is s h o w n to be possible to e s t i m a t e t h e t h e r m o p h y s i c a l p r o p e r t i e s of t h e TiC, including, glass transition temperature, thermal conductivity and solid/liquid interface energy. PERFORMANCE OF SILICON NITRIDE CUTTING TOOL I N S E R T S MADE BY GAS P R E S S U R E SINTERING
E. Besenyei a n d R. Porat, (ISCAR, Maalot, Israel), Int J Refractory Metals & Hard Materials, Vol 11, No 2, 1992, 121126.SiaN4, w i t h a d d i t i v e s , c u t t i n g tool i n s e r t s w e r e m a d e by CIP a n d g a s pressure sintering. The effects of composition oxide content, s t r u c t u r e a n d process variables on cutting p e r f o r m a n c e were assessed. It is r e p o r t e d t h a t t h e performance of t h e gas pressure sintered i n s e r t s is c o m p a r a b l e to h o t p r e s s e d materials. ADVANCES IN COATING OF TOOLS
U. K6nig. ( K r u p p - W i d i a GmbH, Essen, G e r m a n y ) , Powder Metall Int. Vol 24, No 5, 1992, 297-302. Recent d e v e l o p m e n t s in c o a t e d h a r d m a t e r i a l s are discussed with reference to substrate and coating materials and m e t h o d s of application. C e m e n t e d carbide substrates, TiN, TiC a n d a l u m i n a coatings and chemical and physical vapour deposition methods, including plasma techniques, are considered. DAWN OF THE HARDMETAL AGE
H. Kolaska, (Krupp-Widia GmbH, Essen, Germany), Powder Metall Int, Vol 24, No 5, 1992, 311-314. An outline of the development h a r d m e t a l s is p r e s e n t e d . V a c u u m a r c melting, sintering of fine grained carbides, infiltration of p o r o u s W a n d t h e use of WC are considered. Cutting tool inserts for a wide range of applications are reviewed. The p a p e r gives a n i n s i g h t i n t o t h e evolution of carbide cutting tools. EXPLOSIVE COMPACTION OF SILICON NITRIDE AND CARBIDE POWDERS AND WHISKERS
H. Miura et al, ( K u m a m o t o University, Kumamoto, J a p a n ) , J Japan Soc Powder
54 MPR March 1993
LITERATURE
REVIEW
and Powder Metallurgy, Vo 39, No 4, 1992, 266-271. (In J a p a n e s e ) . Explosive c o m p a c t i o n of Si3N4 a n d SiC powder a n d whisker m i x t u r e s is described. A m a n d r e l inserted in t h e core of t h e compact is r e p o r t e d to result in increased densification a n d reduction of t h e incidence of cracking. The explosively c o m p a c t e d materials are said to require lower sintering temperatures a n d t h i s is a t t r i b u t e d to r a p i d particle m o v e m e n t a n d cleaning of surfaces. PREPARATION AND P R O P E R T I E S OF TITANIUM CARBIDE-CARBON COMPOSITE MATERIALS
S.W. Kim et al (Tohuku University, Sendai, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 39, No 4, 1992, 291-294. (In Japanese). P r o d u c t i o n of TiC/C c o a t i n g s , w i t h compositional gradients, CVD, i s described. The coating is d e p o s i t e d in a TiC14-CH4-H2 a t m o s p h e r e . T h e t h e r m a l p r o p e r t i e s are r e p o r t e d to be influenced by c o m p o s i t i o n a n d morphology of t h e C r i c h p h a s e a n d m i c r o voids. T h e r m a l conductivity for TIC-50 mol% C was said to be close to t h a t of CVD TiC. E F F E C T S OF D I S P E R S I O N ON SINTERING OF ATOMIZED H S S POWDERS
P.A. A n d r i e v s k y a n d N.K. Kasmamytov, Poroshkovaya Metallurgiya, No 1O, 1991, 11-14. (In Russian). A s t u d y of changes of density, particle shape, microstructure, m i c r o h a r d n e s s a n d electrical resistivity of HSS powders d u r i n g vacuum sintering is described. Characteristics of sintering at t e m p e r a t u r e s close to t h e onset of liquid p h a s e sintering are noted. The role of C diffusion in d e t e r m i n i n g t h e h a r d n e s s a t p o i n t s of c o n t a c t b e t w e e n p a r t i c l e s is discussed. CORRELATION B E T W E E N CARBON AND CARBIDE FORMING E L E M E N T S AND STRUCTURE AND P R O P E R T I E S OF S I N T E R E D H S S
Y.M. Skrychenko et al, Poroshkovaya Metallurgiya, No 10, 1991, 64-69. (In Russian). The effects of composition o n s t r u c t u r e a n d properties of PM HSS was investigated. It is s h o w n t h a t t h e d i s p e r s i o n a n d d i s t r i b u t i o n of excess carbides d e p e n d s on a correlation between t h e c o n c e n t r a t i o n s of C a n d c a r b i d e forming elements. It is s u g g e s t e d t h a t a n o v e r s a t u r a t i o n of C provides a m e t h o d of s t r u c t u r e dispersion d u r i n g a t o m i z a t i o n a t fast cooling rates. INFLUENCE OF S P U T T E R I N G CONDITIONS ON MORPHOLOGY OF T U N G S T E N CARBIDE-COBALT FILMS
A. Cavaleiro et al, Thin Solid F i l m s Vol 213,
No 1, 1992, 6-12. An i n v e s t i g a t i o n of t h e s i n t e r i n g of A1203/Sic n a n o c o m p o s i t e s is described. Three stages in t h e process are identified. At 1000 to 1350°C t h e A12Oa 7 to t r a n s f o r m a t i o n occurred. The second stage is characterized by sub-grain f o r m a t i o n a n d rotation. In t h e t h i r d stage t h e large grains grow by grain b o u n d a r y migration. SILICON CARBIDE-ALUMINAYTTERBIUM OXIDE COMPOSITE MATERIALS
M. Omori et al, (Tohoku University, Sendai, J a p a n ) , J.Japan Soc, Powder and Powder Metallurgy Vol 39, No 3, 1992, 488-491. (In Japanese). The synthesis of a composite consisting of SIC-50 wtt% (Yb2Oa-33% A12Oa) by sintering a t 1825°C in N is described. A d e n s e composite is formed a n d it is s h o w n t o c o n t a i n ~SiC a n d Yb4A1209. It is suggested that a martensitic t r a n s f o r m a t i o n may occur in t h e Yb4A12O9 matrix. The s t r e n g t h is r e p o r t e d to be 500 MPa.
Intermetalli© materials REACTIVE SINTERING OF BORON D O P E D NICKEL ALUMINIDE
KS. Hwang a n d Y.C. Lu, (Taiwan National University, Taipei, Taiwan), Powder Metall Int, Vol 24, No 5, 1992, 279-283. Reactive sintering of Ni3A1, in t h e r a n g e 24 to 27 at% a n d d o p e d with 0.1 wt% B, was investigated. It is r e p o r t e d t h a t t h e a d d i t i o n of B results in reduced density a n d t h a t p a r t s w i t h 24% A1 h a v e t h e b e s t c o m b i n a t i o n of s h a p e r e t e n t i o n a n d ductility. The effect of h e a t i n g rate on t h e reactive sintering reaction is outlined. At high h e a t i n g r a t e s t h e e x o t h e r m i c r e a c t i o n s t a r t s at 540 to 640°C a n d at slow r a t e s Ni2al 3 is formed as a n i n t e r m e d i a t e a n d acts as a b a r r i e r to t h e f o r m a t i o n of NiaA1 resulting in low s i n t e r e d density. INVESTIGATION OF SYNTHESIS OF TITANIUM ALUMINIDE COMPOSITES BY COMBUSTION REACTION
H. Mabuchi et al (University of Osaka, Osaka, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 39, No 6, 1992, 468473. (In J a p a n e s e ) . The p r o p e r t i e s of TiA1 are discussed w i t h regard to low room t e m p e r a t u r e t o u g h n e s s a n d low high t e m p e r a t u r e s t r e n g t h a n d a n investigation to improve these by i n c o r p o r a t i o n of c e r a m i c p a r t i c l e s is described. Powder m i x t u r e s Ti-AI-C or TiA1-BN were subjected to reaction synthesis a n d TiAI-Ti2A1C or TiA1-Ti2AIN-TiB2 were formed in w h i c h t h e r e was a find dispersion of t h e carbide or boride in a TiA1 matrix.
SIMULATION OF LASER Q U E N C H I N G TO A S S E S S THERMOPHYSICAL P R O P E R T I E S OF TITANIUM CARBIDE
P~ B~chli a n d A. Batter, (University of Berne, Berne, Switzerland), Int J Refractory Metals & Hard Materials, Vol 11, No 2, 1992, 113-119. Nanosecond laser q u e n c h i n g of TIC was e x a m i n e d by c o m p u t e r s i m u l a t i o n a n d experiment. The model allows e x a m i n a t i o n of laser induced melting a n d crystallization on cooling. By c o m p a r i s o n of the model predictions and the e x p e r i m e n t a l results it is s h o w n to be possible to e s t i m a t e t h e t h e r m o p h y s i c a l p r o p e r t i e s of t h e TiC, including, glass transition temperature, thermal conductivity and solid/liquid interface energy. PERFORMANCE OF SILICON NITRIDE CUTTING TOOL I N S E R T S MADE BY GAS P R E S S U R E SINTERING
E. Besenyei a n d R. Porat, (ISCAR, Maalot, Israel), Int J Refractory Metals & Hard Materials, Vol 11, No 2, 1992, 121126.SiaN4, w i t h a d d i t i v e s , c u t t i n g tool i n s e r t s w e r e m a d e by CIP a n d g a s pressure sintering. The effects of composition oxide content, s t r u c t u r e a n d process variables on cutting p e r f o r m a n c e were assessed. It is r e p o r t e d t h a t t h e performance of t h e gas pressure sintered i n s e r t s is c o m p a r a b l e to h o t p r e s s e d materials. ADVANCES IN COATING OF TOOLS
U. K6nig. ( K r u p p - W i d i a GmbH, Essen, G e r m a n y ) , Powder Metall Int. Vol 24, No 5, 1992, 297-302. Recent d e v e l o p m e n t s in c o a t e d h a r d m a t e r i a l s are discussed with reference to substrate and coating materials and m e t h o d s of application. C e m e n t e d carbide substrates, TiN, TiC a n d a l u m i n a coatings and chemical and physical vapour deposition methods, including plasma techniques, are considered. DAWN OF THE HARDMETAL AGE
H. Kolaska, (Krupp-Widia GmbH, Essen, Germany), Powder Metall Int, Vol 24, No 5, 1992, 311-314. An outline of the development h a r d m e t a l s is p r e s e n t e d . V a c u u m a r c melting, sintering of fine grained carbides, infiltration of p o r o u s W a n d t h e use of WC are considered. Cutting tool inserts for a wide range of applications are reviewed. The p a p e r gives a n i n s i g h t i n t o t h e evolution of carbide cutting tools. EXPLOSIVE COMPACTION OF SILICON NITRIDE AND CARBIDE POWDERS AND WHISKERS
H. Miura et al, ( K u m a m o t o University, Kumamoto, J a p a n ) , J Japan Soc Powder
54 MPR March 1993
LITERATURE
REVIEW
and Powder Metallurgy, Vo 39, No 4, 1992, 266-271. (In J a p a n e s e ) . Explosive c o m p a c t i o n of Si3N4 a n d SiC powder a n d whisker m i x t u r e s is described. A m a n d r e l inserted in t h e core of t h e compact is r e p o r t e d to result in increased densification a n d reduction of t h e incidence of cracking. The explosively c o m p a c t e d materials are said to require lower sintering temperatures a n d t h i s is a t t r i b u t e d to r a p i d particle m o v e m e n t a n d cleaning of surfaces. PREPARATION AND P R O P E R T I E S OF TITANIUM CARBIDE-CARBON COMPOSITE MATERIALS
S.W. Kim et al (Tohuku University, Sendai, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 39, No 4, 1992, 291-294. (In Japanese). P r o d u c t i o n of TiC/C c o a t i n g s , w i t h compositional gradients, CVD, i s described. The coating is d e p o s i t e d in a TiC14-CH4-H2 a t m o s p h e r e . T h e t h e r m a l p r o p e r t i e s are r e p o r t e d to be influenced by c o m p o s i t i o n a n d morphology of t h e C r i c h p h a s e a n d m i c r o voids. T h e r m a l conductivity for TIC-50 mol% C was said to be close to t h a t of CVD TiC. E F F E C T S OF D I S P E R S I O N ON SINTERING OF ATOMIZED H S S POWDERS
P.A. A n d r i e v s k y a n d N.K. Kasmamytov, Poroshkovaya Metallurgiya, No 1O, 1991, 11-14. (In Russian). A s t u d y of changes of density, particle shape, microstructure, m i c r o h a r d n e s s a n d electrical resistivity of HSS powders d u r i n g vacuum sintering is described. Characteristics of sintering at t e m p e r a t u r e s close to t h e onset of liquid p h a s e sintering are noted. The role of C diffusion in d e t e r m i n i n g t h e h a r d n e s s a t p o i n t s of c o n t a c t b e t w e e n p a r t i c l e s is discussed. CORRELATION B E T W E E N CARBON AND CARBIDE FORMING E L E M E N T S AND STRUCTURE AND P R O P E R T I E S OF S I N T E R E D H S S
Y.M. Skrychenko et al, Poroshkovaya Metallurgiya, No 10, 1991, 64-69. (In Russian). The effects of composition o n s t r u c t u r e a n d properties of PM HSS was investigated. It is s h o w n t h a t t h e d i s p e r s i o n a n d d i s t r i b u t i o n of excess carbides d e p e n d s on a correlation between t h e c o n c e n t r a t i o n s of C a n d c a r b i d e forming elements. It is s u g g e s t e d t h a t a n o v e r s a t u r a t i o n of C provides a m e t h o d of s t r u c t u r e dispersion d u r i n g a t o m i z a t i o n a t fast cooling rates. INFLUENCE OF S P U T T E R I N G CONDITIONS ON MORPHOLOGY OF T U N G S T E N CARBIDE-COBALT FILMS
A. Cavaleiro et al, Thin Solid F i l m s Vol 213,
No 1, 1992, 6-12. An i n v e s t i g a t i o n of t h e s i n t e r i n g of A1203/Sic n a n o c o m p o s i t e s is described. Three stages in t h e process are identified. At 1000 to 1350°C t h e A12Oa 7 to t r a n s f o r m a t i o n occurred. The second stage is characterized by sub-grain f o r m a t i o n a n d rotation. In t h e t h i r d stage t h e large grains grow by grain b o u n d a r y migration. SILICON CARBIDE-ALUMINAYTTERBIUM OXIDE COMPOSITE MATERIALS
M. Omori et al, (Tohoku University, Sendai, J a p a n ) , J.Japan Soc, Powder and Powder Metallurgy Vol 39, No 3, 1992, 488-491. (In Japanese). The synthesis of a composite consisting of SIC-50 wtt% (Yb2Oa-33% A12Oa) by sintering a t 1825°C in N is described. A d e n s e composite is formed a n d it is s h o w n t o c o n t a i n ~SiC a n d Yb4A1209. It is suggested that a martensitic t r a n s f o r m a t i o n may occur in t h e Yb4A12O9 matrix. The s t r e n g t h is r e p o r t e d to be 500 MPa.
Intermetalli© materials REACTIVE SINTERING OF BORON D O P E D NICKEL ALUMINIDE
KS. Hwang a n d Y.C. Lu, (Taiwan National University, Taipei, Taiwan), Powder Metall Int, Vol 24, No 5, 1992, 279-283. Reactive sintering of Ni3A1, in t h e r a n g e 24 to 27 at% a n d d o p e d with 0.1 wt% B, was investigated. It is r e p o r t e d t h a t t h e a d d i t i o n of B results in reduced density a n d t h a t p a r t s w i t h 24% A1 h a v e t h e b e s t c o m b i n a t i o n of s h a p e r e t e n t i o n a n d ductility. The effect of h e a t i n g rate on t h e reactive sintering reaction is outlined. At high h e a t i n g r a t e s t h e e x o t h e r m i c r e a c t i o n s t a r t s at 540 to 640°C a n d at slow r a t e s Ni2al 3 is formed as a n i n t e r m e d i a t e a n d acts as a b a r r i e r to t h e f o r m a t i o n of NiaA1 resulting in low s i n t e r e d density. INVESTIGATION OF SYNTHESIS OF TITANIUM ALUMINIDE COMPOSITES BY COMBUSTION REACTION
H. Mabuchi et al (University of Osaka, Osaka, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 39, No 6, 1992, 468473. (In J a p a n e s e ) . The p r o p e r t i e s of TiA1 are discussed w i t h regard to low room t e m p e r a t u r e t o u g h n e s s a n d low high t e m p e r a t u r e s t r e n g t h a n d a n investigation to improve these by i n c o r p o r a t i o n of c e r a m i c p a r t i c l e s is described. Powder m i x t u r e s Ti-AI-C or TiA1-BN were subjected to reaction synthesis a n d TiAI-Ti2A1C or TiA1-Ti2AIN-TiB2 were formed in w h i c h t h e r e was a find dispersion of t h e carbide or boride in a TiA1 matrix.