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PM science and technology
PM
characteristics and atmosphere discussed a n d e x a m p l e s given.
are
Coatings MODELLING OF TEMPERATURE GRADIENTS AND STRESS-STRAIN DISTRIBUTIONS DURING PLASMA SPRAYING
B. Borgerding et al (CompoTherm Surface Technology Ltd., Skye, Germany), Powder Metall. Int., Vol 24, No 4, 1992, 240-245. The origins a n d t h e factors affecting t h e m a g n i t u d e of stress-strain distributions in plasma sprayed coatings on ceramic s u b s t r a t e s is discussed. A model, using finite element methods, is presented. The a p p r o a c h is said to offer a n insight into physical, mechanical and chemical p h e n o m e n a d u r i n g p l a s m a spraying a n d the m e c h a n i s m s responsible for t h e build up of stresses a n d strains, t h e i m p o r t a n c e of controlling t h e m a g n i t u d e of stresses a n d strains is emphasized.
HIGH VELOCITY OXY-FUEL SPRAYING PROMISES B E T T E R COATINGS
AJ. Sturgeon (The Welding Inst, Camb r i d g e ) , Metals and Materials, Vol 8, No 10 1992, 547-548. High velocity oxy-fuel t h e r m a l spraying for a p p l i c a t i o n of p o w d e r c o a t i n g s is described with regard to e q u i p m e n t a n d t h e m a t e r i a l s w h i c h are a m e n a b l e to spraying. Lower porosities in the deposited coatings are r e p o r t e d t h a n for several other coating methods. Applications, including c e m e n t e d carbides, are outiined.
Composites E F F E C T OF FIBRE DISTRIBUTION ON INFILTRATION AND FRACTURE OF CARBON FIBRE REINFORCED ALUMINIUM COMPOSITES
)L Zhenhai et al (Hebei Inst. of Technology, Tianjin, China), Z. MetaUkunde, Vol 82, No 10, 1991, 766-768. The p r o d u c t i o n of C fibre reinforced Al alloys by i n f i l t r a t i o n is described. The m e t h o d allowed t h e use of low pressures (0.7 MPa) for infiltration in spite of t h e low wettability of t h e metal on the fibre. The effects of fibre a r r a n g e m e n t s on mechanical properties is discussed.
INVESTIGATIONS OF INTERFACES IN ALUMINIUM COMPOSITES REINFORCED WITH NICKEL COATED CARBON F I B R E S
H. Berek et al ( F r e i b e r g e r NE-Metall. GmbH., F r e i b e r - S a c h s e n , G e r m a n y ) , Z.
LITERATURE
REVIEW
Metallkunde, Vol 82, No.10, 1991, 928-934 (in German). The production of C fibre reinforced A1 alloys is described a n d it is shown t h a t a metal coating on the fibre is required. Ni was used for t h e coating. The AI/Ni/C interface was investigated and the p r e s e n c e of A13Ni a n d AlgFeNi w e r e detected but not A14C3. It is suggested t h a t Ni c o a t e d C f i b r e is s u i t e d for reinforcement of A1 alloys. PM PROCESSING OF ALUMINIUMSILICON CARBIDE COMPOSITES
V.V. B h a n u p r a s a d et al (Defence Metallurgical Research Lab., Hyderabad, India), Int. J. Powder Metallurgy, Vol 27, No.3, 1992, 227-235. T h e PM p r o c e s s i n g of A1 a l l o y s reinforced by SiC fibres a n d particles is described. The dispersion of SiC a n d the effects of reinforcement characteristics on m e c h a n i c a l p r o p e r t i e s was investigated. Fibres were r e p o r t e d to give a greater increase in s t r e n g t h which is a t t r i b u t e d to favourable aspect ratio a n d load transfer. Rolling a n d extrusion are c o m p a r e d a n d it is shown t h a t rolling produces s o u n d e r material t h a n extrusion. Increased s t r e n g t h a n d ductility were found after rolling at up to 600°C. Cu coating of t h e SiC was found to be beneficial due to alteration of the A1/ SiC interface.
Hard materials PROPERTIES OF DIAMOND LAPPING FILMS
N. K a w a s h i m a et al, (Tokyo Magnetic Printing Co., Tokyo, J a p a n ) , PM Science and Technology, Vol 3, No 3, 1992, 43-49. The p a p e r d e s c r i b e s a n d d i s c u s s e s s t r u c t u r e s a n d p r o p e r t i e s of d i a m o n d lapping films. Multilayers, monolayers a n d c o m p o s i t e layered m a t e r i a l s c o n t a i n i n g m i c r o n on s u b - m i c r o n sized d i a m o n d particles are considered.
INFLUENCE OF P R E S S U R E SINTERING ON PROPERTIES OF HARDMETALS
A. Doubravsky, J. Svoboda (Pramet-VUPM, Sumperk, Poland), Pokroky Psaskove Metalurgie, No 3-4, 1991, 23-32 (in Czech). Sinter-HIP p r o c e s s i n g of h a r d m e t a l s using new technology is described a n d the results of t e s t s of the effects of process p a r a m e t e r s are presented. Comparison is made with materials conventionally processed. MULTILA_VER COATING OF C E M E N T E D CARBIDES FOR MACHINING
M. Dziembowski ( H u t a Baildon, Katowice, Poland) MetaU Proszkow, Vol 25, No 1, 1992, 15-19 (in Polish).
The p r o d u c t i o n of coatings on c e m e n t e d carbides by chemical v a p o u r deposition (CVD) is described. Multi layer coatings of TiN, TiC, T i ( C , N ) a n d A12)O3 a r e considered. The c u t t i n g p e r f o r m a n c e of cutting tools is outlined.
ULTRAFINE SILICON CARBIDE POWDER PRODUCED BY ARC PLASMA J E T VAPOUR REACTION PROCESS
H. Rongfang, L. Chengfu. (Inst. of Metal Research, Shenyang, China), PM Technology, Vol 10, No 3, 1992, 178-181, (in Chinese). Analysis of particle size, size distribution, morphology and grain s t r u c t u r e was investigated with reference to t h e effects of powder characteristics. It is shown t h a t synthesis is initiated at lower t e m p e r a t u r e s for coarser powders.
STRUCTURE OF SURFACE OF COBALT C E M E N T E D T U N G S T E N CARBIDE TREATED BY ELECTRICAL DISCHARGE
N. Tsuchiya et al (Fiji Die Co, Tokyo, J a p a n ) J. Japan Soc. Powder and Powder Metallurgy, Vol 39, No 2, 1992, 98-102 (in Japanese). A s t u d y of t h e effects of electrical discharge machining on the surface s t r u c t u r e of WC a n d WC-Co alloys is reported. W2C, ~WC1 x (B1 structure) a n d WC were detected b u t no Co or q phase. This is d i s t r i b u t e d to rapid non-equilibrium cooling of t h e liquid p h a s e produced by t h e electrical discharge.
SYNTHESIS OF THIN ALUMINIUM NITRIDE FILMS BY DUAL ION BEAM SPUTTERING
E. Kamijo et al (Ryukoku University, Shiga, J a p a n ) J. Japan Soc. Powder and Powder Metallurgy, Vol 39, No 2, 1992, 119-121, (in J a p a n e s e ) . The p r o d u c t i o n of t h i n AIN films on a s u b s t r a t e by s p u t t e r i n g A1 in an N ion b e a m is described. It is shown t h a t the film may grow epitaxially on t h e substrate.
A STUDY OF SURFACE RESIDUAL S T R E S S E S ON A COATED CARBIDE
T. Yamamoto (Dijet Industrial Co. Ltd., Osaka, J a p a n ) J. Japan Soc, Powder and Powder Metallurgy, Vol 39, No 3, 1992, 163-167, (in J a p a n e s e ) . Residual stress m e a s u r e m e n t s in TiC or TiN coatings on a WC-Co s u b s t r a t e a n d in t h e WC of t h e s u b s t r a t e are reported. It is shown t h a t coatings applied by physical v a p o u r deposition were superior to those deposited by chemical methods.
MPR February 1993 41
characteristics and atmosphere discussed a n d e x a m p l e s given.
are
Coatings MODELLING OF TEMPERATURE GRADIENTS AND STRESS-STRAIN DISTRIBUTIONS DURING PLASMA SPRAYING
B. Borgerding et al (CompoTherm Surface Technology Ltd., Skye, Germany), Powder Metall. Int., Vol 24, No 4, 1992, 240-245. The origins a n d t h e factors affecting t h e m a g n i t u d e of stress-strain distributions in plasma sprayed coatings on ceramic s u b s t r a t e s is discussed. A model, using finite element methods, is presented. The a p p r o a c h is said to offer a n insight into physical, mechanical and chemical p h e n o m e n a d u r i n g p l a s m a spraying a n d the m e c h a n i s m s responsible for t h e build up of stresses a n d strains, t h e i m p o r t a n c e of controlling t h e m a g n i t u d e of stresses a n d strains is emphasized.
HIGH VELOCITY OXY-FUEL SPRAYING PROMISES B E T T E R COATINGS
AJ. Sturgeon (The Welding Inst, Camb r i d g e ) , Metals and Materials, Vol 8, No 10 1992, 547-548. High velocity oxy-fuel t h e r m a l spraying for a p p l i c a t i o n of p o w d e r c o a t i n g s is described with regard to e q u i p m e n t a n d t h e m a t e r i a l s w h i c h are a m e n a b l e to spraying. Lower porosities in the deposited coatings are r e p o r t e d t h a n for several other coating methods. Applications, including c e m e n t e d carbides, are outiined.
Composites E F F E C T OF FIBRE DISTRIBUTION ON INFILTRATION AND FRACTURE OF CARBON FIBRE REINFORCED ALUMINIUM COMPOSITES
)L Zhenhai et al (Hebei Inst. of Technology, Tianjin, China), Z. MetaUkunde, Vol 82, No 10, 1991, 766-768. The p r o d u c t i o n of C fibre reinforced Al alloys by i n f i l t r a t i o n is described. The m e t h o d allowed t h e use of low pressures (0.7 MPa) for infiltration in spite of t h e low wettability of t h e metal on the fibre. The effects of fibre a r r a n g e m e n t s on mechanical properties is discussed.
INVESTIGATIONS OF INTERFACES IN ALUMINIUM COMPOSITES REINFORCED WITH NICKEL COATED CARBON F I B R E S
H. Berek et al ( F r e i b e r g e r NE-Metall. GmbH., F r e i b e r - S a c h s e n , G e r m a n y ) , Z.
LITERATURE
REVIEW
Metallkunde, Vol 82, No.10, 1991, 928-934 (in German). The production of C fibre reinforced A1 alloys is described a n d it is shown t h a t a metal coating on the fibre is required. Ni was used for t h e coating. The AI/Ni/C interface was investigated and the p r e s e n c e of A13Ni a n d AlgFeNi w e r e detected but not A14C3. It is suggested t h a t Ni c o a t e d C f i b r e is s u i t e d for reinforcement of A1 alloys. PM PROCESSING OF ALUMINIUMSILICON CARBIDE COMPOSITES
V.V. B h a n u p r a s a d et al (Defence Metallurgical Research Lab., Hyderabad, India), Int. J. Powder Metallurgy, Vol 27, No.3, 1992, 227-235. T h e PM p r o c e s s i n g of A1 a l l o y s reinforced by SiC fibres a n d particles is described. The dispersion of SiC a n d the effects of reinforcement characteristics on m e c h a n i c a l p r o p e r t i e s was investigated. Fibres were r e p o r t e d to give a greater increase in s t r e n g t h which is a t t r i b u t e d to favourable aspect ratio a n d load transfer. Rolling a n d extrusion are c o m p a r e d a n d it is shown t h a t rolling produces s o u n d e r material t h a n extrusion. Increased s t r e n g t h a n d ductility were found after rolling at up to 600°C. Cu coating of t h e SiC was found to be beneficial due to alteration of the A1/ SiC interface.
Hard materials PROPERTIES OF DIAMOND LAPPING FILMS
N. K a w a s h i m a et al, (Tokyo Magnetic Printing Co., Tokyo, J a p a n ) , PM Science and Technology, Vol 3, No 3, 1992, 43-49. The p a p e r d e s c r i b e s a n d d i s c u s s e s s t r u c t u r e s a n d p r o p e r t i e s of d i a m o n d lapping films. Multilayers, monolayers a n d c o m p o s i t e layered m a t e r i a l s c o n t a i n i n g m i c r o n on s u b - m i c r o n sized d i a m o n d particles are considered.
INFLUENCE OF P R E S S U R E SINTERING ON PROPERTIES OF HARDMETALS
A. Doubravsky, J. Svoboda (Pramet-VUPM, Sumperk, Poland), Pokroky Psaskove Metalurgie, No 3-4, 1991, 23-32 (in Czech). Sinter-HIP p r o c e s s i n g of h a r d m e t a l s using new technology is described a n d the results of t e s t s of the effects of process p a r a m e t e r s are presented. Comparison is made with materials conventionally processed. MULTILA_VER COATING OF C E M E N T E D CARBIDES FOR MACHINING
M. Dziembowski ( H u t a Baildon, Katowice, Poland) MetaU Proszkow, Vol 25, No 1, 1992, 15-19 (in Polish).
The p r o d u c t i o n of coatings on c e m e n t e d carbides by chemical v a p o u r deposition (CVD) is described. Multi layer coatings of TiN, TiC, T i ( C , N ) a n d A12)O3 a r e considered. The c u t t i n g p e r f o r m a n c e of cutting tools is outlined.
ULTRAFINE SILICON CARBIDE POWDER PRODUCED BY ARC PLASMA J E T VAPOUR REACTION PROCESS
H. Rongfang, L. Chengfu. (Inst. of Metal Research, Shenyang, China), PM Technology, Vol 10, No 3, 1992, 178-181, (in Chinese). Analysis of particle size, size distribution, morphology and grain s t r u c t u r e was investigated with reference to t h e effects of powder characteristics. It is shown t h a t synthesis is initiated at lower t e m p e r a t u r e s for coarser powders.
STRUCTURE OF SURFACE OF COBALT C E M E N T E D T U N G S T E N CARBIDE TREATED BY ELECTRICAL DISCHARGE
N. Tsuchiya et al (Fiji Die Co, Tokyo, J a p a n ) J. Japan Soc. Powder and Powder Metallurgy, Vol 39, No 2, 1992, 98-102 (in Japanese). A s t u d y of t h e effects of electrical discharge machining on the surface s t r u c t u r e of WC a n d WC-Co alloys is reported. W2C, ~WC1 x (B1 structure) a n d WC were detected b u t no Co or q phase. This is d i s t r i b u t e d to rapid non-equilibrium cooling of t h e liquid p h a s e produced by t h e electrical discharge.
SYNTHESIS OF THIN ALUMINIUM NITRIDE FILMS BY DUAL ION BEAM SPUTTERING
E. Kamijo et al (Ryukoku University, Shiga, J a p a n ) J. Japan Soc. Powder and Powder Metallurgy, Vol 39, No 2, 1992, 119-121, (in J a p a n e s e ) . The p r o d u c t i o n of t h i n AIN films on a s u b s t r a t e by s p u t t e r i n g A1 in an N ion b e a m is described. It is shown t h a t the film may grow epitaxially on t h e substrate.
A STUDY OF SURFACE RESIDUAL S T R E S S E S ON A COATED CARBIDE
T. Yamamoto (Dijet Industrial Co. Ltd., Osaka, J a p a n ) J. Japan Soc, Powder and Powder Metallurgy, Vol 39, No 3, 1992, 163-167, (in J a p a n e s e ) . Residual stress m e a s u r e m e n t s in TiC or TiN coatings on a WC-Co s u b s t r a t e a n d in t h e WC of t h e s u b s t r a t e are reported. It is shown t h a t coatings applied by physical v a p o u r deposition were superior to those deposited by chemical methods.
MPR February 1993 41