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Friction and wear of sintered aluminium-lead-copper-magnesium alloy
PM
LITERATURE
REVIEW
characteristics d u r i n g h o t upsetting. It is r e p o r t e d t h a t t h e densification rate a n d flow stress increased as t h e %SiC increased for any given density. Optical microscopy was used to show t h a t t h e SiC particle d i s t r i b u t i o n in t h e sintered composite is n e a r uniform.
determined. A linear r e l a t i o n s h i p between s t r a i n rate a n d t r u e stress is reported. It is suggested t h a t t h e c o n t r i b u t i o n of effective stress to high t e m p e r a t u r e d e f o r m a t i o n is small a n d t h a t t h e s t r u c t u r e changes d u r i n g stress r e l a x a t i o n are similar to t h o s e d u r i n g steady s t a t e creep deformation.
Al-16vol%Pb-3%Mg were investigated a n d c o m p a r e d with t h o s e of leaded bronze. It is reported that the mechanical properties d e p e n d o n Cu c o n t e n t a n d porosity. The h i g h e s t tensile s t r e n g t h was 120 MPa a t 3%Cu. Wear p r o p e r t i e s were inferior to t h o s e of leaded bronze.
MICROSTRUCTURAL DEVELOPMENT DURING HOT WORKING OF ALUMINIUM POWDER ALLOY
STRUCTURAL F E A T U R E S O F MECHANICALLY ALLOYED ALUMINIUM-IRON-NICKE L ALLOYS
TRIBOLOGICAL BEHAVIOUR OF MECHANICALLY ALLOYED ALUMINIUM-IRON-CHROMIUM ALLOYS
A. Greasley, H.Y. Shi (The Open University, Milton Keynes, UK), Powder Metallur~,
W. Erde et al ( H a r b i n Inst. of Technology, Harbin, C h i n a ) , PM Technology, Vol 1 i,
G.H. B o r h a n i et al ( I n d i a n Inst. of Technology, Bombay, India), Trans. PM Assoc. of
Vol 36, No 4, 1993, 288-292.
No 3, 1993, 165-170. (In Chinese).
India, VoI 20, 1993, 7-12.
A s t u d y of m i c r o s t r u c t u r a l evolution during h o t working of a sintered 2014 A2 alloy is described. The sequence is r e p o r t e d to be removal of t h e rapidly solidified s t r u c t u r e of t h e powder, e l i m i n a t i o n of prior particle boundaries, onset of partial of complete recrystallization and d e v e l o p m e n t of h o t shortness. These are characterized in t e r m s of t e m p e r a t u r e s , strain and strain rates. Reference m i c r o g r a p h s are given which can be used for i n d e p e n d e n t verification of models used in t h e r m o m e c h a n i c a l analysis of m e t a l working processes such as e x t r u s i o n a n d powder forging.
Particle size, s h a p e a n d size d i s t r i b u t i o n a n d s t r u c t u r a l evolution d u r i n g MA of Al 10%Fe-4%Ni, were investigated. C h a n g e s of solid s o l u b i l i t y a n d effects of m i l l i n g conditions on microstructure and m i c r o g r a i n size w e r e m e a s u r e d . It is shown t h a t grain size d i m i n i s h e s a n d solid solubility increases simultaneously. It is p o s t u l a t e d t h a t a layered s t r u c t u r e m u s t form in t h e initial milling stages.
It is r e p o r t e d t h a t A1-8wt%Fe-2%Cr alloy powders h a d b e e n p r o d u c e d by high energy m i l l i n g of A1, Fe a n d f e r r o c h r o m i u m powders. The MA powders were v a c u u m d e g a s s e d a n d h o t p r e s s e d to n e a r full density. Improved wear resistance, c o m p a r e d with s i n t e r e d a n d w r o u g h t A1 a l l o y s , is r e p o r t e d . T h e m a i n w e a r m e c h a n i s m is s h o w n to be de-lamination. The structure contains A16(Fe,Cr) precipitates i n a n A1 m a t r i x s u p e r s a t u r a t e d with Fe.
PARTICLE REINFORCED ALUMINIUM AND MAGNESIUM METAL MATRIX COMPOSITES
D,I. Lloyd (Alcan I n t e r n a t i o n a l Ltd., Kingston, C a n a d a ) , Int. Materials Reviews,
Vol 39, No 1, 1994, 1-45. Particle reinforced Al a n d Mg alloy m e t a l m a t r i x composites are reviewed with regard to types of reinforcement a n d processing m e t h o d s i n c l u d i n g PM a n d casting. In sintered products matrix and reinforcement compositions are i n d e p e n d e n t , b u t for i n g o t p r o c e s s i n g t h e r e a r e close r e l a t i o n s h i p s b e t w e e n them. Distribution of reinforcement in t h e m a t r i x , r e l a t i v e t o p r o c e s s r o u t e , is discussed. The need to a t t a i n a n e a r full density on PM alloys, by m e a n s of secondary processing, is emphasized. Spray forming, infiltration a n d m o l t e n m e t a l m i x i n g are considered. Mechanical properties are discussed with reference to t h e effects of process methods. Subject a r e a s requiring f u r t h e r s t u d y are identified. S T R E S S RELATION AND DEFORMATION MECHANISM A T HIGH TEMPERATURE IN ALUMINIUM-IRON ALLOY
N. M a t s u d a et al (Yamagata University, Yonezawa, J a p a n ) , J. Japan Inst. of Metals,
Vol 57, No 9, 1993, 1027-1034. (In Japanese). Stress r e l a x a t i o n in s i n t e r e d A1-8wt%Fe alloys was investigated a t 300 to 400°C. Strain r a t e s for steady s t a t e creep a n d for t h e o n s e t of stress r e l a x a t i o n are compared. Work h a r d e n i n g a n d recovery r a t e s were
50 MPR September 1994
F A T I G U E AND INTERNAL F R I C T I O N IN A S I N T E R E D ALUMINIUM ALLOY A. Hara, M. Yokota ( N a t i o n a l College, Takoaka, J a p a n ) , J. Japan Soc. Powder
and Powder Metallurgy, Vol 40, No 6, 1993, 598-601. (In Japanese). The fatigue properties of AI-5wt%Cu-O, 5%Mg-O, 8%Si a t 91.5% d e n s i t y w e r e investigated using a cantilever internal friction device actuated electromagnetically. It is r e p o r t e d t h a t t h e r e s o n a n t frequency correlated well w i t h i n t e r n a l friction a n d was reduced a t t h e onset of fatigue cracking. Cracks p r o p a g a t e d along grain boundaries. OBSERVATION OF DENSITY DISTRIBUTION IN S I N T E R E D A L U M I N I U M U S I N G ACOUSTIC MICROSCOPY
N. Hirose, J. Asami (Metropolitan Industrial Technology Centre, Tokyo, J a p a n ) , J. Japan
Soc. Powder and Powder Metallurgy, Vol 40, No 6, 1993, 602-605. (In Japanese). The use of acoustic microscopy to s t u d y d e n s i t y d i s t r i b u t i o n i n s i n t e r e d tel is described. The acoustic images are r e p o r t e d to correlate well with tensile test results. A relative intensity echo m e t h o d was used a n d clearly revealed zones of low d e n s i t y . F r a c t u r e in t h e t e n s i l e t e s t s i n i t i a t e d in a r e a s o f low d e n s i t y o r lamellar defects detected before testing. FRICTION AND WEAR OF S I N T E R E D ALUMINIUM-LEAD-COPPE RM A G N E S I U M ALLOY
K. Nishiyama et al (Science University of Tokyo, Tokyo, J a p a n ) , J. Japan Soc. Powder
and Powder Metallur~, Vol 40, No 6, 1993, 645-648. (In Japanese). The effects of a d d i t i o n s of Cu on t h e friction a n d w e a r p r o p e r t i e s of a s i n t e r e d
USE OF POWDER METALLURGY FOR FABRICATION O F ALUMINIUMURANIUM COMPOSITE REACTOR F U E L S
P.V. Hegde et al (Atomic Research Centre, Bombay, India), Trans. PM Assoc. of India,
Vol 20, 1993, 27-31. The p a p e r describes t h e use of PM to produce A1 or A1-Mg clad A1-UAI3, A1-UAI3, A1-UaOs a n d A1-UaSi2 composites for use as reactor fuel elements. P r e p a r a t i o n of t h e U oxide, a l u m n i d e a n d silicide p o w d e r s , compaction of the composites and f a b r i c a t i o n of t h e clad p l a t e s by h o t rolling are described. It is r e p o r t e d t h a t t h e use of PM alloys allows h i g h e r loading of t h e fuel e l e m e n t s with U c o m p o u n d s t h a n a n ingot route. Use was m a d e of low enriched U. EXOTHERMIC S I N T E R I N G OF ALUMINIUM WITH A HIGH C O N T E N T OF C O P P E R
A.P. Savickii, G.N. R o m a n o v ( R u s s i a n A c a d e m y of Sciences, Tomsk, R u s s i a ) ,
Science of Sintering, Vol 25, No 1/2, 1993, 9-14. Dilatometric studies of sintering of A1(30 to 35)5Cu compacts, in which e x o t h e r m i c reactions occur, are described. The e x o t h e r m i c reaction results in liquid p h a s e s i n t e r i n g in f u r n a c e s b e l o w t h e eutectic temperature with consequent s h r i n k a g e of t h e compacts. MICROSTRUCTURE AND MECHANICAL P R O P E R T I E S OF ALUMINIUMA L U M I N I U M CARBIDE COMPOSITES
G. J a n g g et al (Technical University of Vienna, Vienna, A u s t r i a ) , Science of Sinter-
ing, Vol 25, No 1/2, 1993, 15-24.
LITERATURE
REVIEW
characteristics d u r i n g h o t upsetting. It is r e p o r t e d t h a t t h e densification rate a n d flow stress increased as t h e %SiC increased for any given density. Optical microscopy was used to show t h a t t h e SiC particle d i s t r i b u t i o n in t h e sintered composite is n e a r uniform.
determined. A linear r e l a t i o n s h i p between s t r a i n rate a n d t r u e stress is reported. It is suggested t h a t t h e c o n t r i b u t i o n of effective stress to high t e m p e r a t u r e d e f o r m a t i o n is small a n d t h a t t h e s t r u c t u r e changes d u r i n g stress r e l a x a t i o n are similar to t h o s e d u r i n g steady s t a t e creep deformation.
Al-16vol%Pb-3%Mg were investigated a n d c o m p a r e d with t h o s e of leaded bronze. It is reported that the mechanical properties d e p e n d o n Cu c o n t e n t a n d porosity. The h i g h e s t tensile s t r e n g t h was 120 MPa a t 3%Cu. Wear p r o p e r t i e s were inferior to t h o s e of leaded bronze.
MICROSTRUCTURAL DEVELOPMENT DURING HOT WORKING OF ALUMINIUM POWDER ALLOY
STRUCTURAL F E A T U R E S O F MECHANICALLY ALLOYED ALUMINIUM-IRON-NICKE L ALLOYS
TRIBOLOGICAL BEHAVIOUR OF MECHANICALLY ALLOYED ALUMINIUM-IRON-CHROMIUM ALLOYS
A. Greasley, H.Y. Shi (The Open University, Milton Keynes, UK), Powder Metallur~,
W. Erde et al ( H a r b i n Inst. of Technology, Harbin, C h i n a ) , PM Technology, Vol 1 i,
G.H. B o r h a n i et al ( I n d i a n Inst. of Technology, Bombay, India), Trans. PM Assoc. of
Vol 36, No 4, 1993, 288-292.
No 3, 1993, 165-170. (In Chinese).
India, VoI 20, 1993, 7-12.
A s t u d y of m i c r o s t r u c t u r a l evolution during h o t working of a sintered 2014 A2 alloy is described. The sequence is r e p o r t e d to be removal of t h e rapidly solidified s t r u c t u r e of t h e powder, e l i m i n a t i o n of prior particle boundaries, onset of partial of complete recrystallization and d e v e l o p m e n t of h o t shortness. These are characterized in t e r m s of t e m p e r a t u r e s , strain and strain rates. Reference m i c r o g r a p h s are given which can be used for i n d e p e n d e n t verification of models used in t h e r m o m e c h a n i c a l analysis of m e t a l working processes such as e x t r u s i o n a n d powder forging.
Particle size, s h a p e a n d size d i s t r i b u t i o n a n d s t r u c t u r a l evolution d u r i n g MA of Al 10%Fe-4%Ni, were investigated. C h a n g e s of solid s o l u b i l i t y a n d effects of m i l l i n g conditions on microstructure and m i c r o g r a i n size w e r e m e a s u r e d . It is shown t h a t grain size d i m i n i s h e s a n d solid solubility increases simultaneously. It is p o s t u l a t e d t h a t a layered s t r u c t u r e m u s t form in t h e initial milling stages.
It is r e p o r t e d t h a t A1-8wt%Fe-2%Cr alloy powders h a d b e e n p r o d u c e d by high energy m i l l i n g of A1, Fe a n d f e r r o c h r o m i u m powders. The MA powders were v a c u u m d e g a s s e d a n d h o t p r e s s e d to n e a r full density. Improved wear resistance, c o m p a r e d with s i n t e r e d a n d w r o u g h t A1 a l l o y s , is r e p o r t e d . T h e m a i n w e a r m e c h a n i s m is s h o w n to be de-lamination. The structure contains A16(Fe,Cr) precipitates i n a n A1 m a t r i x s u p e r s a t u r a t e d with Fe.
PARTICLE REINFORCED ALUMINIUM AND MAGNESIUM METAL MATRIX COMPOSITES
D,I. Lloyd (Alcan I n t e r n a t i o n a l Ltd., Kingston, C a n a d a ) , Int. Materials Reviews,
Vol 39, No 1, 1994, 1-45. Particle reinforced Al a n d Mg alloy m e t a l m a t r i x composites are reviewed with regard to types of reinforcement a n d processing m e t h o d s i n c l u d i n g PM a n d casting. In sintered products matrix and reinforcement compositions are i n d e p e n d e n t , b u t for i n g o t p r o c e s s i n g t h e r e a r e close r e l a t i o n s h i p s b e t w e e n them. Distribution of reinforcement in t h e m a t r i x , r e l a t i v e t o p r o c e s s r o u t e , is discussed. The need to a t t a i n a n e a r full density on PM alloys, by m e a n s of secondary processing, is emphasized. Spray forming, infiltration a n d m o l t e n m e t a l m i x i n g are considered. Mechanical properties are discussed with reference to t h e effects of process methods. Subject a r e a s requiring f u r t h e r s t u d y are identified. S T R E S S RELATION AND DEFORMATION MECHANISM A T HIGH TEMPERATURE IN ALUMINIUM-IRON ALLOY
N. M a t s u d a et al (Yamagata University, Yonezawa, J a p a n ) , J. Japan Inst. of Metals,
Vol 57, No 9, 1993, 1027-1034. (In Japanese). Stress r e l a x a t i o n in s i n t e r e d A1-8wt%Fe alloys was investigated a t 300 to 400°C. Strain r a t e s for steady s t a t e creep a n d for t h e o n s e t of stress r e l a x a t i o n are compared. Work h a r d e n i n g a n d recovery r a t e s were
50 MPR September 1994
F A T I G U E AND INTERNAL F R I C T I O N IN A S I N T E R E D ALUMINIUM ALLOY A. Hara, M. Yokota ( N a t i o n a l College, Takoaka, J a p a n ) , J. Japan Soc. Powder
and Powder Metallurgy, Vol 40, No 6, 1993, 598-601. (In Japanese). The fatigue properties of AI-5wt%Cu-O, 5%Mg-O, 8%Si a t 91.5% d e n s i t y w e r e investigated using a cantilever internal friction device actuated electromagnetically. It is r e p o r t e d t h a t t h e r e s o n a n t frequency correlated well w i t h i n t e r n a l friction a n d was reduced a t t h e onset of fatigue cracking. Cracks p r o p a g a t e d along grain boundaries. OBSERVATION OF DENSITY DISTRIBUTION IN S I N T E R E D A L U M I N I U M U S I N G ACOUSTIC MICROSCOPY
N. Hirose, J. Asami (Metropolitan Industrial Technology Centre, Tokyo, J a p a n ) , J. Japan
Soc. Powder and Powder Metallurgy, Vol 40, No 6, 1993, 602-605. (In Japanese). The use of acoustic microscopy to s t u d y d e n s i t y d i s t r i b u t i o n i n s i n t e r e d tel is described. The acoustic images are r e p o r t e d to correlate well with tensile test results. A relative intensity echo m e t h o d was used a n d clearly revealed zones of low d e n s i t y . F r a c t u r e in t h e t e n s i l e t e s t s i n i t i a t e d in a r e a s o f low d e n s i t y o r lamellar defects detected before testing. FRICTION AND WEAR OF S I N T E R E D ALUMINIUM-LEAD-COPPE RM A G N E S I U M ALLOY
K. Nishiyama et al (Science University of Tokyo, Tokyo, J a p a n ) , J. Japan Soc. Powder
and Powder Metallur~, Vol 40, No 6, 1993, 645-648. (In Japanese). The effects of a d d i t i o n s of Cu on t h e friction a n d w e a r p r o p e r t i e s of a s i n t e r e d
USE OF POWDER METALLURGY FOR FABRICATION O F ALUMINIUMURANIUM COMPOSITE REACTOR F U E L S
P.V. Hegde et al (Atomic Research Centre, Bombay, India), Trans. PM Assoc. of India,
Vol 20, 1993, 27-31. The p a p e r describes t h e use of PM to produce A1 or A1-Mg clad A1-UAI3, A1-UAI3, A1-UaOs a n d A1-UaSi2 composites for use as reactor fuel elements. P r e p a r a t i o n of t h e U oxide, a l u m n i d e a n d silicide p o w d e r s , compaction of the composites and f a b r i c a t i o n of t h e clad p l a t e s by h o t rolling are described. It is r e p o r t e d t h a t t h e use of PM alloys allows h i g h e r loading of t h e fuel e l e m e n t s with U c o m p o u n d s t h a n a n ingot route. Use was m a d e of low enriched U. EXOTHERMIC S I N T E R I N G OF ALUMINIUM WITH A HIGH C O N T E N T OF C O P P E R
A.P. Savickii, G.N. R o m a n o v ( R u s s i a n A c a d e m y of Sciences, Tomsk, R u s s i a ) ,
Science of Sintering, Vol 25, No 1/2, 1993, 9-14. Dilatometric studies of sintering of A1(30 to 35)5Cu compacts, in which e x o t h e r m i c reactions occur, are described. The e x o t h e r m i c reaction results in liquid p h a s e s i n t e r i n g in f u r n a c e s b e l o w t h e eutectic temperature with consequent s h r i n k a g e of t h e compacts. MICROSTRUCTURE AND MECHANICAL P R O P E R T I E S OF ALUMINIUMA L U M I N I U M CARBIDE COMPOSITES
G. J a n g g et al (Technical University of Vienna, Vienna, A u s t r i a ) , Science of Sinter-
ing, Vol 25, No 1/2, 1993, 15-24.