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Effect of C content on hardenability of a PM steel
properties of the Cu. U n d e r liquid phase sintering the perfection of the penetr-ation of c o p p e r into hhe interstices be~,veen ti~e Me p a r t i c l e s is t h e p r i n c i p a l proper..-.' d e t e r m i n i n g factor_ Liquid p h a s e sinterin~ l e a d s to h i g h e r v a l u e s of m e c h a n i c : i l properties.
( - - ~ C were pre,:iuced. The t r a n s i b ~ a t i o n kineth:s u~der v a ~ o u s co~iing conditions fr,-~m [h- austenitic s t a t e were investigated b,7:h expe~mer,::aiiy a n d by m a t h e m a t i c ~ si mulation_
Niobium
Iron and steel E F F E C T S O F COLD ROLLING AND A ~ ~ G ON T H E DA~MPING CAPACITY (L-N~TEP~,N~L F R I C T I O N ) OF Pb LNFILTRATED S I N T E R E D IRON COMPACTS M Yokota, et "el, J. Japan Soc. P~u'der and Pawder Metalhtrgy, Vol 37, No 4, 539-545. In Japanese. I n t e r n a l friction m e a s u r e m e n t s were m a d e o n Pb i n f i l t r a t e d s i n t e r e d iron c o m p a c t s which were subsequently cold rolled a n d t h e n annealed. The infiltration volume ratio ,~-as up to 31.6% Pb, t h e cold rolling gave reductions of up to 40% a n d a n n e a l i n g w a s c a r r i e d o u t a t 200=C. Increase in %Pb increases the d a m p i n g capacity as does increase in % cold work. T h e t e n s i l e s t r e n g t h i n c r e a s e s to a m a x i m u m t h e n decreases with increase in % cold rolling. A n n e a l i n g r e d u c e s t h e d a m p i n g capacity of specimens which h a d been cold rolled. The internal friction of s i n t e r e d iron with 31.6% infiltrated lead, which h a d been reduced by 40% by cold rolling, was comparable with t h a t of a flake g r a p h i t e cast iron. INFILTRATION OF COPPER INTO S I N T E R E D STEEL D Yi, L Chuanxi, (Universiw of Science a n d Technology, Beijing, China), PM Technology, Vol 8, No 3, 1990, 130-135. tn Chinese. The p r o p e r t i e s a n d s t r u c t u r e of Cu infiltrated sintered steel h a s been studied with regard to characteristics of the powder a n d t h e sintered c o m p a c t s a n d process parameters. E F F E C T S OF LONG TERM STORAGE ON STRUCTURE AND P R O P E R T I E S OF STEEL POWDERS L A S h a p o r e n k o , e t al, Poroskovaya Metalluryia, No 3, 1990, 99-101. In Russian. Structural changes in powdered steel which h a d been stored for six m o n t h s a n d one year were investigated. It was shown t h a t uniformity of m a r t e n s i t e increases d u r i n g s t o r a g e w i t h o u t c h a n g e in t h e matrix. Less s c a t t e r is observed in the m e a s u r e d mechanical properties. E F F E C T O F C C O N T E N ' r ON HARDENABILITY OF A PM S T E E L Y G Gurevich, et al, Poroskovaya Metalhtrg/a, No 4, 1990, 55-59. In Russian. Specimens of a steel wSth 0.3, 0.5 and
52 MPR January 1991
of PM m a g n e t i c composite materials are c~utlined. The d e v e l o p m e n t of two materials, one with Fe powder in a n ~M m a t r i x a n d the ocher with Fe powder in a plastic matrix, for u s e in m a g n e t i c c o r e s a t h i g h frequencies, is described.
INTERRELATION B E T ~ E E N POWDER P R O P E R T I E S , P R E S S I N G A~N'D SLNTERING CONq)ITIONS ON S T R U C T U R E OF POROUS Nb Y Le~inskT, et al, Porosk
Coatings BASICS O F PHYSICAL VAPOUR D E P O S I T I O N (PVD) P R O C E S S E S K Mohwald, ( U n i v e r s i t y of D o r t m u n d , Dortmund, Germany), Metall, Vol 44, No 3, 1990, 279-273. In German. T h r e e p r o c e s s e s for PVD, v a c u u m evaporation, s p u t t e r i n g a n d ion p l a t i n g are reviewed. The m e c h a n i s m s of t h e formation and growth of films are d e s c r i b e d . T h e i n f l u e n c e of p r o c e s s p a r a m e t e r s are d e m o n s t r a t e d . E m p h a s i s is placed on the ion-plating m e t h o d since it c o m b i n e s a d v a n t a g e s of t h e o t h e r t~vo processes.
Electrical and magnetic materials hL
111111 VI
II
I [ I IH III I '
III
I
MAGNETIC PROPERTIES OF C O M P R E S S E D A M O R P H O U S ALLOY POWD E RS T Sato, J.Japan Soc. Powder and Powder Metallurgy, Vol 37, No 4, 532-538. In Japanese. Magnetic cores were pressed from rapidly solidified, w a t e r atomized powders. It ~was found t h a t increase of particle size a n d relative d e n s i ~ e n h a n c e s DC magnetic properties b u t AC magnetic properties are reduced. It is suggested t h a t the variation of coercivity is due to stress ~ r i a t i o n in t h e cores. PROPERTIES OF bIAGNETIC C O M P O S I T E MATERIALS M Abe, et al, (Materials Res Laboratory, Kobe Steel Ltd, Kobe, J a p a n ) , Kobelco Technology Retriew, No 8, 1990, 1-4. Production, properties a n d a p p l i c a t i o n s
S~%°THESIS OF Bi-Sr-Ca-Cu OXIDE SLTERCONDUCTING ~&TERIALS FROM ULTRAFINE PO~TDERS S Ohno, et al, J.Japan Foe. Powder and Pawder Metallurgy, Vol 37, No 5, 1990, 705707. In Japanese. Ultrafine p o w d e r s were p r o d u c e d by hydrogen p l a s m a - m e t a l reaction, In the case of Bi a n d Cu t h e p o w d e r s were elemental but t h e Ca a n d Sr powders were found to be the hydroxides. Sintering a n d superconducting properties were studied using m i x t u r e s of t h e powders. Differential t h e r m a l analysis (DTA) showed the most favourable sintering range to be 830 to 870°C and, w h e n sintered for t h r e e to five hours, a high proportion of the s u p e r c o n d u c t i n g p h a s e (with a critical t e m p e r a t u r e (Tc) of 80K was formed. Longer sintering times gave a s u p e r c o n d u c t i n g p h a s e with a higher Tc of l l 0 t ( It is suggested t h a t the high Tc p h a s e can be p r e p a r e d by re-sintering a compact containing a high proportion of the low Tc phase.
Hard materials and tool steels ]
MICROSTRUCTURES OF WC-TiC-Co C E M E N T E D CARBIDES WITH RARE EARTH ( R E ) A D D I T I O N S L Zhonglin, (Research Institute of Zhuzhou C e m e n t e d Carbide I n d u s t r y Co, Hunan, China), fnt J. Refractory Metals & Hard Matvr/als, Vol 9, No 3, 1990, 128-131. The s t r u c t u r e of WC-TiC-Co h a s been examined by optical and electron microscopy, and electron and X-ray diffraction. Alloys with rare earth additions were also studied. It was shown t h a t the RE is d i s t r i b u t e d within the Corich p h a s e a n d t h a t t h e ecCo to eCo t r a n s f o r m a t i o n is i m p e d e d by t h e RE addition. The suppression of the t r a n s f o r m a t i o n results in a n increase in bending s t r e n g t h a n d impact t o u g h n e s s of t h e c e m e n t e d carbide. CHARACTERIZATION O F T H E I N T E R F A C E S IN CHEMICAL VAPOUR D E P O S I T E D (CVD) COATINGS ON C E M E N T E D CARBIDES C C h a t f i e l d , (AB S a n d v i k C o r o m a n t , S t o c k h o l m , S w e d e n ) , Int J.Refraetory Metals & Hard Materials, Vol 9, No 3, 1990, 132-138. Coating of TiC on a cemented carbide substrate, Al203 on TiC a n d AlzO3 on TiN were a p p l i e d by CVD. T h e i n t e r f a c e s
( - - ~ C were pre,:iuced. The t r a n s i b ~ a t i o n kineth:s u~der v a ~ o u s co~iing conditions fr,-~m [h- austenitic s t a t e were investigated b,7:h expe~mer,::aiiy a n d by m a t h e m a t i c ~ si mulation_
Niobium
Iron and steel E F F E C T S O F COLD ROLLING AND A ~ ~ G ON T H E DA~MPING CAPACITY (L-N~TEP~,N~L F R I C T I O N ) OF Pb LNFILTRATED S I N T E R E D IRON COMPACTS M Yokota, et "el, J. Japan Soc. P~u'der and Pawder Metalhtrgy, Vol 37, No 4, 539-545. In Japanese. I n t e r n a l friction m e a s u r e m e n t s were m a d e o n Pb i n f i l t r a t e d s i n t e r e d iron c o m p a c t s which were subsequently cold rolled a n d t h e n annealed. The infiltration volume ratio ,~-as up to 31.6% Pb, t h e cold rolling gave reductions of up to 40% a n d a n n e a l i n g w a s c a r r i e d o u t a t 200=C. Increase in %Pb increases the d a m p i n g capacity as does increase in % cold work. T h e t e n s i l e s t r e n g t h i n c r e a s e s to a m a x i m u m t h e n decreases with increase in % cold rolling. A n n e a l i n g r e d u c e s t h e d a m p i n g capacity of specimens which h a d been cold rolled. The internal friction of s i n t e r e d iron with 31.6% infiltrated lead, which h a d been reduced by 40% by cold rolling, was comparable with t h a t of a flake g r a p h i t e cast iron. INFILTRATION OF COPPER INTO S I N T E R E D STEEL D Yi, L Chuanxi, (Universiw of Science a n d Technology, Beijing, China), PM Technology, Vol 8, No 3, 1990, 130-135. tn Chinese. The p r o p e r t i e s a n d s t r u c t u r e of Cu infiltrated sintered steel h a s been studied with regard to characteristics of the powder a n d t h e sintered c o m p a c t s a n d process parameters. E F F E C T S OF LONG TERM STORAGE ON STRUCTURE AND P R O P E R T I E S OF STEEL POWDERS L A S h a p o r e n k o , e t al, Poroskovaya Metalluryia, No 3, 1990, 99-101. In Russian. Structural changes in powdered steel which h a d been stored for six m o n t h s a n d one year were investigated. It was shown t h a t uniformity of m a r t e n s i t e increases d u r i n g s t o r a g e w i t h o u t c h a n g e in t h e matrix. Less s c a t t e r is observed in the m e a s u r e d mechanical properties. E F F E C T O F C C O N T E N ' r ON HARDENABILITY OF A PM S T E E L Y G Gurevich, et al, Poroskovaya Metalhtrg/a, No 4, 1990, 55-59. In Russian. Specimens of a steel wSth 0.3, 0.5 and
52 MPR January 1991
of PM m a g n e t i c composite materials are c~utlined. The d e v e l o p m e n t of two materials, one with Fe powder in a n ~M m a t r i x a n d the ocher with Fe powder in a plastic matrix, for u s e in m a g n e t i c c o r e s a t h i g h frequencies, is described.
INTERRELATION B E T ~ E E N POWDER P R O P E R T I E S , P R E S S I N G A~N'D SLNTERING CONq)ITIONS ON S T R U C T U R E OF POROUS Nb Y Le~inskT, et al, Porosk
Coatings BASICS O F PHYSICAL VAPOUR D E P O S I T I O N (PVD) P R O C E S S E S K Mohwald, ( U n i v e r s i t y of D o r t m u n d , Dortmund, Germany), Metall, Vol 44, No 3, 1990, 279-273. In German. T h r e e p r o c e s s e s for PVD, v a c u u m evaporation, s p u t t e r i n g a n d ion p l a t i n g are reviewed. The m e c h a n i s m s of t h e formation and growth of films are d e s c r i b e d . T h e i n f l u e n c e of p r o c e s s p a r a m e t e r s are d e m o n s t r a t e d . E m p h a s i s is placed on the ion-plating m e t h o d since it c o m b i n e s a d v a n t a g e s of t h e o t h e r t~vo processes.
Electrical and magnetic materials hL
111111 VI
II
I [ I IH III I '
III
I
MAGNETIC PROPERTIES OF C O M P R E S S E D A M O R P H O U S ALLOY POWD E RS T Sato, J.Japan Soc. Powder and Powder Metallurgy, Vol 37, No 4, 532-538. In Japanese. Magnetic cores were pressed from rapidly solidified, w a t e r atomized powders. It ~was found t h a t increase of particle size a n d relative d e n s i ~ e n h a n c e s DC magnetic properties b u t AC magnetic properties are reduced. It is suggested t h a t the variation of coercivity is due to stress ~ r i a t i o n in t h e cores. PROPERTIES OF bIAGNETIC C O M P O S I T E MATERIALS M Abe, et al, (Materials Res Laboratory, Kobe Steel Ltd, Kobe, J a p a n ) , Kobelco Technology Retriew, No 8, 1990, 1-4. Production, properties a n d a p p l i c a t i o n s
S~%°THESIS OF Bi-Sr-Ca-Cu OXIDE SLTERCONDUCTING ~&TERIALS FROM ULTRAFINE PO~TDERS S Ohno, et al, J.Japan Foe. Powder and Pawder Metallurgy, Vol 37, No 5, 1990, 705707. In Japanese. Ultrafine p o w d e r s were p r o d u c e d by hydrogen p l a s m a - m e t a l reaction, In the case of Bi a n d Cu t h e p o w d e r s were elemental but t h e Ca a n d Sr powders were found to be the hydroxides. Sintering a n d superconducting properties were studied using m i x t u r e s of t h e powders. Differential t h e r m a l analysis (DTA) showed the most favourable sintering range to be 830 to 870°C and, w h e n sintered for t h r e e to five hours, a high proportion of the s u p e r c o n d u c t i n g p h a s e (with a critical t e m p e r a t u r e (Tc) of 80K was formed. Longer sintering times gave a s u p e r c o n d u c t i n g p h a s e with a higher Tc of l l 0 t ( It is suggested t h a t the high Tc p h a s e can be p r e p a r e d by re-sintering a compact containing a high proportion of the low Tc phase.
Hard materials and tool steels ]
MICROSTRUCTURES OF WC-TiC-Co C E M E N T E D CARBIDES WITH RARE EARTH ( R E ) A D D I T I O N S L Zhonglin, (Research Institute of Zhuzhou C e m e n t e d Carbide I n d u s t r y Co, Hunan, China), fnt J. Refractory Metals & Hard Matvr/als, Vol 9, No 3, 1990, 128-131. The s t r u c t u r e of WC-TiC-Co h a s been examined by optical and electron microscopy, and electron and X-ray diffraction. Alloys with rare earth additions were also studied. It was shown t h a t the RE is d i s t r i b u t e d within the Corich p h a s e a n d t h a t t h e ecCo to eCo t r a n s f o r m a t i o n is i m p e d e d by t h e RE addition. The suppression of the t r a n s f o r m a t i o n results in a n increase in bending s t r e n g t h a n d impact t o u g h n e s s of t h e c e m e n t e d carbide. CHARACTERIZATION O F T H E I N T E R F A C E S IN CHEMICAL VAPOUR D E P O S I T E D (CVD) COATINGS ON C E M E N T E D CARBIDES C C h a t f i e l d , (AB S a n d v i k C o r o m a n t , S t o c k h o l m , S w e d e n ) , Int J.Refraetory Metals & Hard Materials, Vol 9, No 3, 1990, 132-138. Coating of TiC on a cemented carbide substrate, Al203 on TiC a n d AlzO3 on TiN were a p p l i e d by CVD. T h e i n t e r f a c e s