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Production of CuNiAl shape memory alloys (SMA) by powder metallurgy
PM
P R O P E R T I E S A N D APPLICATIONS O F PM AI ALLOYS I~ Hummert, (PEAK Werkstoffe, Germany),
Metall, Kunstoffe, Vol 28, No 17, 1990, 5459. In Dutch. A1 carbide a n d oxide have been used to e n h a n c e t h e mechanical properties of PM A1 alloys. Elastic m o d u l u s above 300 GPa is reported.
Beryllium IRRADIATION E M B R I T T L E M E N T OF PM Be-Mo ALLOYS AT H I G H TEMPERATURES V.F. Z e l e n s k y , e t al, Poroshkavaya MetaUurgiya, No 9, 1990, 69-72. In Russian. High temperature irradiation e m b r i t t l e m e n t (HTIE) of Be-Mo alloys h a s been investigated. The powders were produced either by a milling or a distillation process. The alloys p r e p a r e d by distillation showed less e m b r i t t l e m e n t t h a n those m a d e by milling a n d PM techniques. The specimens were subjected to a dose of 6 x 1018 e l / c m 2 of 7 rays a t 225 MeV.
Copper LABORATORY S I M U I ~ T I O N OF COMMERCIAL BRASS FLAKE MANUFACTURE J.D. J a m e s , et al, ( U n i v e r s i t y College, Swansea, UK), Powder Metallurgy, Vol 33, No 3, 1990, 247-252. Processes for t h e conversion of brass powder to flake have been investigated a n d are reviewed. Powder h a s been converted to flake on a pilot scale by milling a n d it was shown t h a t t h e p r o d u c t was of commercial quality for a range of applications.
P R O D U C T I O N O F Cu-Ni-AI SHAPE MEMORY ALLOYS ( S M A ) BY POWDER METALLURGY Y-T. Choi, I-S. Chung, (Kyungpook National University, Taegu, Korea), J. Korean Inst. of Metals, Vol 28, No 10, 1990, 857-865. In Korean. Cu-Ni-Al s h a p e m e m o r y alloys (SMA) were p r o d u c e d by PM technology, including HIP, w i t h t h e objective of a t t a i n i n g a n improvement in the mechanical properties. Increases in tensile s t r e n g t h of 25-60% a n d 90-110% increase in elongation were r e p o r t e d in spite of a n increase in t h e grain size.
72 MPR May 1991
LITERATURE
REVIEW
Iron and Steel SURFACE STRUCTURE OF A STEEL A F T E R ABRASIVE T R E A T M E N T A.A. A d a m o v s k i , e t al, Poroshkavaya Metallurgiya, No 9, 1990, 59-63. In Russian. The surface structure of a steel with V a d d e d h a s been investigated after a b r a d i n g with A1203 or BN wheels. A reduction in h a r d n e s s a t t h e surface was n o t e d a n d this was greater in t h e case of t h e A1203 a b r a d e d specimens. This was a t t r i b u t e d to t h e larger a m o u n t of r e t a i n e d austenite, which was m e a s u r e d by X - r a y analysis, a n d w a s considered to be a cause of the h a r d n e s s drop. A n o t h e r cause was considered to be a change in t h e s t r u c t u r e of t h e carbides. USE OF ELECTRON MICROSCOPY TO STUDY THE STRUCTURE OF POWDER IRON WITH D I F F E R I N G P O R O S I T I E S A.E. Kushchevski, et al, Poroshkavaya MetaUurgiya, No 9, 1990, 91-95. In Russian. R e d u c e d Fe p o w d e r c o m p a c t s , w i t h p o r o s i t i e s in t h e r a n g e 4 to 35%, in i n c r e m e n t s of 0.3%, were p r e p a r e d by single compaction a n d sintering a n d t h e f r a c t u r e c h a r a c t e r i s t i c s i n v e s t i g a t e d by electron microscopy. It was found t h a t t h e fracture characteristics were a function of t h e porosity a n d t h a t p a r t i c u l a r fracture characteristics were associated with p a r t i c u l a r porosity ranges. CHARACTERISTICS OF HIGH STRENGTH SINTERED COMPONENTS USING LOW ALLOY STEEL POWDER T. Miyashita, et al, (Kobe Steel, J a p a n ) , Kobelco Technology Review, No 9, 1990, 14. The d e v e l o p m e n t of two steel powders, a partially prealloyed Fe-4%Ni-l.5%Cu0.5%Mo a n d a fully prealloyed Fe-0.5%Ni0.5%Mo, i n t e n d e d for t h e p r o d u c t i o n of high s t r e n g t h steel c o m p o n e n t s is r e p o r t e d . I m p a c t s t r e n g t h s of 2-3 kgf.m/cm 2 a n d tensile s t r e n g t h s of 120-130 kgf/mm 2 are claimed. D I M E N S I O N A L C H A N G E S DURING SINTERING OF Fe-BASED POWDERS Z. Takata, et al,
(Kobe Steel, J a p a n ) , Kobelco Technology Review, No 9, 1990, 5-13. Dimensional changes during the sintering of Fe-2%Cu-0.8%Graphite0.75%Zn s t e a r a t e c o m p a c t s h a v e b e e n measured. An e x p a n s i o n in t h e ~Fe range was observed a n d this was a t t r i b u t e d to a c a r b u r i z a t i o n r e a c t i o n w h i c h influences sintering behaviour. The dimensional changes became smaller with carburization during heating a n d greater during cooling.
D E N S I F I C A T I O N OF VACUUM S I N T E R E D FINE CARBONYL F e POWDER K. Hayashi, T-W. Lim, (University of Tokyo, J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 2, 1990, 224-230. In J~panese. The densilication of carbonyl Fe-base compacts with additions of A1, Cr, Mn, Nb, Si a n d Ti was studied. Some alloys were incompletely densified and this was a t t r i b u t e d to gas pressure in closed pores. Additions of A1, Ti, Nb a n d V gave full densification. E F F E C T OF B ON T H E D E N S I F I C A T I O N AND MECHANICAL P R O P E R T I E S OF SINTERED F e COMPACTS T. Nishida, et al, ( N i p p o n Steel Corp, K a w a s a k i , J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 10, 1990, 1147-1153. In Japanese. The effect of B on t h e densification, s t r u c t u r e a n d properties of sintered Feb a s e d c o m p a c t s was i n v e s t i g a t e d w i t h reference to t h e type of m a s t e r alloy used to a d d t h e B. With t h e use of Ni-B alloy, sintering was activated by t h e formation of a liquid eutectic. Densities of 99% were a t t a i n e d by use of a n Fe-Ni-B m a s t e r alloy. Rapid densitication was observed a t 1130°C in compacts m a d e from 16~m powder a n d a t 1150°C w h e n 8 0 9 m powder was used. Increase in t h e a m o u n t of m a s t e r alloy increased t h e s t r e n g t h of t h e material. D E N S I F I C A T I O N P R O C E S S E S DURING SINTERING OF Fe-Cr COMPACTS M. Kamada, et al, (Kyusyu University, Fukuoka, J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 11, 1990, 1243-1249. In J a p a nese. Cr steels, with 7 to 11 wt% Cr were s i n t e r e d in t h e single phase- regions T (austenite) or 5 (5-ferrite) or in t h e two p h a s e region a + 8. Dimensional changes were measured. It was found t h a t shrinkage was greater in specimens sintered in t h e state due to greater self diffusion. S h r i n k a g e in t h e t w o - p h a s e r e g i o n is d e t e r m i n e d by t h e p r o p o r t i o n of t h e 5 p h a s e p r e s e n t a n d t h e law of m i x t u r e s was found to apply. M O R P H O L O G I E S OF POWDERS FOR MICROCRYSTALLINE STEELS S. Michelland-Abb6, et al, (University of Caen, France), Mere. et Etudes Scientifiqzws Rev. MetaU., Vol 87, No 12, 1990, 786794. In French. Automatic image analysis a n d electron microscopy have been used to e x a m i n e t h e morphologies of steel powders p r o d u c e d by gas a n d w a t e r atomization. Particle sizes range from 10~m upwards. Powders were sieved into seven fractions from 10 to 200~tm. The powders were used to m a k e
P R O P E R T I E S A N D APPLICATIONS O F PM AI ALLOYS I~ Hummert, (PEAK Werkstoffe, Germany),
Metall, Kunstoffe, Vol 28, No 17, 1990, 5459. In Dutch. A1 carbide a n d oxide have been used to e n h a n c e t h e mechanical properties of PM A1 alloys. Elastic m o d u l u s above 300 GPa is reported.
Beryllium IRRADIATION E M B R I T T L E M E N T OF PM Be-Mo ALLOYS AT H I G H TEMPERATURES V.F. Z e l e n s k y , e t al, Poroshkavaya MetaUurgiya, No 9, 1990, 69-72. In Russian. High temperature irradiation e m b r i t t l e m e n t (HTIE) of Be-Mo alloys h a s been investigated. The powders were produced either by a milling or a distillation process. The alloys p r e p a r e d by distillation showed less e m b r i t t l e m e n t t h a n those m a d e by milling a n d PM techniques. The specimens were subjected to a dose of 6 x 1018 e l / c m 2 of 7 rays a t 225 MeV.
Copper LABORATORY S I M U I ~ T I O N OF COMMERCIAL BRASS FLAKE MANUFACTURE J.D. J a m e s , et al, ( U n i v e r s i t y College, Swansea, UK), Powder Metallurgy, Vol 33, No 3, 1990, 247-252. Processes for t h e conversion of brass powder to flake have been investigated a n d are reviewed. Powder h a s been converted to flake on a pilot scale by milling a n d it was shown t h a t t h e p r o d u c t was of commercial quality for a range of applications.
P R O D U C T I O N O F Cu-Ni-AI SHAPE MEMORY ALLOYS ( S M A ) BY POWDER METALLURGY Y-T. Choi, I-S. Chung, (Kyungpook National University, Taegu, Korea), J. Korean Inst. of Metals, Vol 28, No 10, 1990, 857-865. In Korean. Cu-Ni-Al s h a p e m e m o r y alloys (SMA) were p r o d u c e d by PM technology, including HIP, w i t h t h e objective of a t t a i n i n g a n improvement in the mechanical properties. Increases in tensile s t r e n g t h of 25-60% a n d 90-110% increase in elongation were r e p o r t e d in spite of a n increase in t h e grain size.
72 MPR May 1991
LITERATURE
REVIEW
Iron and Steel SURFACE STRUCTURE OF A STEEL A F T E R ABRASIVE T R E A T M E N T A.A. A d a m o v s k i , e t al, Poroshkavaya Metallurgiya, No 9, 1990, 59-63. In Russian. The surface structure of a steel with V a d d e d h a s been investigated after a b r a d i n g with A1203 or BN wheels. A reduction in h a r d n e s s a t t h e surface was n o t e d a n d this was greater in t h e case of t h e A1203 a b r a d e d specimens. This was a t t r i b u t e d to t h e larger a m o u n t of r e t a i n e d austenite, which was m e a s u r e d by X - r a y analysis, a n d w a s considered to be a cause of the h a r d n e s s drop. A n o t h e r cause was considered to be a change in t h e s t r u c t u r e of t h e carbides. USE OF ELECTRON MICROSCOPY TO STUDY THE STRUCTURE OF POWDER IRON WITH D I F F E R I N G P O R O S I T I E S A.E. Kushchevski, et al, Poroshkavaya MetaUurgiya, No 9, 1990, 91-95. In Russian. R e d u c e d Fe p o w d e r c o m p a c t s , w i t h p o r o s i t i e s in t h e r a n g e 4 to 35%, in i n c r e m e n t s of 0.3%, were p r e p a r e d by single compaction a n d sintering a n d t h e f r a c t u r e c h a r a c t e r i s t i c s i n v e s t i g a t e d by electron microscopy. It was found t h a t t h e fracture characteristics were a function of t h e porosity a n d t h a t p a r t i c u l a r fracture characteristics were associated with p a r t i c u l a r porosity ranges. CHARACTERISTICS OF HIGH STRENGTH SINTERED COMPONENTS USING LOW ALLOY STEEL POWDER T. Miyashita, et al, (Kobe Steel, J a p a n ) , Kobelco Technology Review, No 9, 1990, 14. The d e v e l o p m e n t of two steel powders, a partially prealloyed Fe-4%Ni-l.5%Cu0.5%Mo a n d a fully prealloyed Fe-0.5%Ni0.5%Mo, i n t e n d e d for t h e p r o d u c t i o n of high s t r e n g t h steel c o m p o n e n t s is r e p o r t e d . I m p a c t s t r e n g t h s of 2-3 kgf.m/cm 2 a n d tensile s t r e n g t h s of 120-130 kgf/mm 2 are claimed. D I M E N S I O N A L C H A N G E S DURING SINTERING OF Fe-BASED POWDERS Z. Takata, et al,
(Kobe Steel, J a p a n ) , Kobelco Technology Review, No 9, 1990, 5-13. Dimensional changes during the sintering of Fe-2%Cu-0.8%Graphite0.75%Zn s t e a r a t e c o m p a c t s h a v e b e e n measured. An e x p a n s i o n in t h e ~Fe range was observed a n d this was a t t r i b u t e d to a c a r b u r i z a t i o n r e a c t i o n w h i c h influences sintering behaviour. The dimensional changes became smaller with carburization during heating a n d greater during cooling.
D E N S I F I C A T I O N OF VACUUM S I N T E R E D FINE CARBONYL F e POWDER K. Hayashi, T-W. Lim, (University of Tokyo, J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 2, 1990, 224-230. In J~panese. The densilication of carbonyl Fe-base compacts with additions of A1, Cr, Mn, Nb, Si a n d Ti was studied. Some alloys were incompletely densified and this was a t t r i b u t e d to gas pressure in closed pores. Additions of A1, Ti, Nb a n d V gave full densification. E F F E C T OF B ON T H E D E N S I F I C A T I O N AND MECHANICAL P R O P E R T I E S OF SINTERED F e COMPACTS T. Nishida, et al, ( N i p p o n Steel Corp, K a w a s a k i , J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 10, 1990, 1147-1153. In Japanese. The effect of B on t h e densification, s t r u c t u r e a n d properties of sintered Feb a s e d c o m p a c t s was i n v e s t i g a t e d w i t h reference to t h e type of m a s t e r alloy used to a d d t h e B. With t h e use of Ni-B alloy, sintering was activated by t h e formation of a liquid eutectic. Densities of 99% were a t t a i n e d by use of a n Fe-Ni-B m a s t e r alloy. Rapid densitication was observed a t 1130°C in compacts m a d e from 16~m powder a n d a t 1150°C w h e n 8 0 9 m powder was used. Increase in t h e a m o u n t of m a s t e r alloy increased t h e s t r e n g t h of t h e material. D E N S I F I C A T I O N P R O C E S S E S DURING SINTERING OF Fe-Cr COMPACTS M. Kamada, et al, (Kyusyu University, Fukuoka, J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 11, 1990, 1243-1249. In J a p a nese. Cr steels, with 7 to 11 wt% Cr were s i n t e r e d in t h e single phase- regions T (austenite) or 5 (5-ferrite) or in t h e two p h a s e region a + 8. Dimensional changes were measured. It was found t h a t shrinkage was greater in specimens sintered in t h e state due to greater self diffusion. S h r i n k a g e in t h e t w o - p h a s e r e g i o n is d e t e r m i n e d by t h e p r o p o r t i o n of t h e 5 p h a s e p r e s e n t a n d t h e law of m i x t u r e s was found to apply. M O R P H O L O G I E S OF POWDERS FOR MICROCRYSTALLINE STEELS S. Michelland-Abb6, et al, (University of Caen, France), Mere. et Etudes Scientifiqzws Rev. MetaU., Vol 87, No 12, 1990, 786794. In French. Automatic image analysis a n d electron microscopy have been used to e x a m i n e t h e morphologies of steel powders p r o d u c e d by gas a n d w a t e r atomization. Particle sizes range from 10~m upwards. Powders were sieved into seven fractions from 10 to 200~tm. The powders were used to m a k e