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Sintering behaviour and strength of FeSiP compacts
College, London, UK), Materials Science and Technology, Vol 6, No 8, 1990, 749-754. (a) A1-5% Cr-2% Zr, (b) A1-6.4% Cr-1, 7% Zr and (c) Al-4% Cr-l% Fe RS powders were c o n s o l i d a t e d by cold p r e s s i n g and hot e x t r u s i o n . Alloy (c) was f o u n d to be easier to e x t r u d e t h a n the others due to p h a s e t r a n s f o r m a t i o n s occuring d u r i n g extrusion. Transverse and longitudinal mechanical properties were obtained from rectangular bars and little difference was found between the two directions. Fracture was found to occur at primary particle boundaries. Structure/property r e l a t i o n s h i p s w e r e i n v e s t i g a t e d . The addition of Zr is more beneficial t h a n the addition of Fe due to the formation of fine intermetallic p h a s e s and reduction of Cr yields a finer a n d m o r e h o m o g e n e o u s microstructure. MECHANICAL T E S T I N G AND MICROSTRUCTURAL ANALYSIS OF E X T R U D E D POWDER ALUMINIUM T.O. Woods et al, Proceedings of Sixth International Congress on E x p e r i m e n t a l Mechanics, Vol 1. Microstructure and mechanical properties of e x t r u d e d PM Al were studied in order to determine fracture mechanisms. Elevated t e m p e r a t u r e testing in tension and compression was used and structural changes were e x a m i n e d by quantitative microscopy. Void c o n t e n t was found to increase with increased tensile deformation and to decrease with increase in compressive strain.
SIGNIFICANCE OF OXIDE SKINS ON POWDER FOR THE QUALITY OF PM A1 MATERIALS H. Schlich, ( E u r o p e a n S p a c e Agency), European Space Agency Report No N9018560/4/XAB, 1989. Surface layers <246> oxides, hydroxides and a b s o r b e d layers, on Al powder, were conditioned by degassing. Mass spectroscopy was used to optimize the degassing process. The composition and c o m p o u n d s t a t u s of t h e layers w e r e characterized by A u g e r a n d X - r a y spectroscopy, prior to and after degassing. In d e g a s s e d a n d v a c u u m c o n s o l i d a t e d materials fewer defects due to the layers were found.
RAPIDLY SOLIDIFIED ( R S ) ALLOYS AND THEIR APPLICATION FOR STRUCTURAL MATERIALS K. Aakamatsu et al, (Kansai University, J a p a n ) , J Japan Soc Heat Treatment, Vol 29, No 5, 1989, 258-263. In Japanese. Attention is drawn to the reason for retarded development of A1 alloys by the
50 MPR April 1991
i n g o t r o u t e , i.e. s e g r e g a t i o n of alloy elements. RS powders and PM have been u s e d to p r e p a r e alloys w i t h i m p r o v e d properties c o m p a r e d to cast and wrought materials. Densification procedures such as pseudo-HIP (e.g. Ceracon) are evaluated.
characterize the structure. Hardness, impact and wear resistance m e a s u r e m e n t s were made. The durability of an alloy Cu18.3% Sn-4.9% AI-2.2% Zn-0.55% Si was greater t h a n t h a t of previously used alloys for the application.
Copper
Iron and steel ............
- -
...............
-Z
......
- ----T
- ---- ........
P
LIQUID PHASE SINTERING OF BINARY Cu ALLOYS
SINTERING BEHAVIOUR AND STRENGTH OF Fe-Si-P COMPACTS
G.S. U p a d h y a y a a n d A. B h a t t a c h a r j e e , (Indian Institute of Technology, Kanpur, India), Int J Powder Metallurgy, Vol 27, No l, 23-27. The liquid p h a s e sintering of Cu base alloys with Ag, Si, Sn and Pb, has been investigated at two sintering t e m p e r a t u r e s for each alloy system. Alloy compositions were selected to give 5 wt% of the liquid p h a s e at e a c h s i n t e r i n g t e m p e r a t u r e . Densification, density, electrical conductivity, m i c r o h a r d n e s s and s t r e s s / s t r a i n r e s p o n s e w e r e e v a l u a t e d . The r e s u l t s are d i s c u s s e d in t e r m s of t h e e l e c t r o n i c s t r u c t u r e of t h e c o m p o n e n t elements in each alloy.
X. Qu et al, (Central South University of Technology, Changsha, Hunan, China), Int J Powder Metallurgy, Vol 27, No l, 9-13. Fe-Si-P compacts with 0.45% P and 0 to 6% Si were p r e p a r e d from Fe, Fe2P and Si p o w d e r s a n d s i n t e r e d in a r e d u c i n g a t m o s p h e r e at ll00°C. During sintering the P alloyed rapidly and e n h a n c e d the dissolving of the Si in the Fe. There was a reduction in solid volume and corresponding shrinkage of the compacts with little change in the relative density. It is suggested t h a t pore shrinkage due to diffusional mass t r a n s p o r t is offset by an i n c r e a s e in p o r e v o l u m e d u e to t h e K i r k e n d a l l effect. An i n c r e a s e in t h e tensile s t r e n g t h in alloys containing up to 4% Si was a t t r i b u t e d to solid solution s t r e n g t h e n i n g . Above 4% Si t h e r e was e m b r i t t l e m e n t of the alloys.
PRODUCTION OF D I S P E R S I O N S T R E N G T H E N E D Cu WITH HEAT RESISTANCE AND HIGH ELECTRICAL CONDUCTIVITY K. Nagata, M. Kumagai, (Sumitomo Light Metals, J a p a n ) , Sumitomo Light Metals Technical Reports, Vol 31, No 1, 1990, 97. In Japanese. A m e t h o d for the production of a Cu alloy, dispersion s t r e n g t h e n e d with A1203, is described. Cu powder alloyed with 0.05 to 3 vvt• p r o d u c e d by atomization. Cu powder surface was oxidized by heating in air at 300°C and mixed with the alloy powder. The powder mixture was c o n s o l i d a t e d a n d p r e s s e d i n t o a Cu container. Heating and hot forming oxidizes the Al and gives a fine dispersion of alumina in the Cu matrix. A 1 2 0 3
w
a
s
OPTIMIZATION OF COMPOSITION OF S I N T E R E D Cu-Sn-A1 ALLOYS L.M. Gurevich and A.K. Reimer, Metalloyed, Term, Obrab, Met, No 5, 1990, 2830. In Russian. The structure and mechanical properties of hot pressed Cu-17 to 20 wt% Sn-1 to 9% A1-0 to 4.4% Zn-0.1 to 1.0% Si w e r e d e t e r m i n e d in o r d e r to d e t e r m i n e t h e o p t i m u m composition of the alloy for use as the matrix in metal bonded d i a m o n d honing bars. X-ray diffraction, microscopy and m i c r o p r o b e analysis were used to
COMPOSITION MICROSTRUCTURE AND MECHANICAL PROPERTY RELATIONS IN S I N T E R E D STAINLESS STEEL A. Molinari et al, (University of Trento, Italy), Int J Powder Metallurgy, Vol 27, No 1, 15-21. Powder samples of 316L stainless steel containing additions of Cu (2, 4 and 9%) were compacted to 6.4 and 6.8 g/cm 3 and sintered at l l 8 0 ° C for 30 or 60 minutes in cracked ammonia. The microstructure was e x a m i n e d and tensile, bend and impact tests carried out. The m e a s u r e m e n t s and structure were correlated with the composition and process parameters. The i m p o r t a n c e of p o r o s i t y and nitrogen c o n t e n t in determination of properties was confirmed. Undissolved Cu in the alloys c a u s e s e m b r i t t l e m e n t . The r e s u l t s are reported to permit the optimization of the production of Cu alloyed 316L stainless steel.
STRUCTURES OF POWDERS AND COATINGS OF IRON-BASE EUTECTIC ALLOYS V.E. Oliker, Poroskovaya MetaUurgiya, No 7, 1990, 29 34. In Russian. Microscopy, X-ray diffraction and X ray
SIGNIFICANCE OF OXIDE SKINS ON POWDER FOR THE QUALITY OF PM A1 MATERIALS H. Schlich, ( E u r o p e a n S p a c e Agency), European Space Agency Report No N9018560/4/XAB, 1989. Surface layers <246> oxides, hydroxides and a b s o r b e d layers, on Al powder, were conditioned by degassing. Mass spectroscopy was used to optimize the degassing process. The composition and c o m p o u n d s t a t u s of t h e layers w e r e characterized by A u g e r a n d X - r a y spectroscopy, prior to and after degassing. In d e g a s s e d a n d v a c u u m c o n s o l i d a t e d materials fewer defects due to the layers were found.
RAPIDLY SOLIDIFIED ( R S ) ALLOYS AND THEIR APPLICATION FOR STRUCTURAL MATERIALS K. Aakamatsu et al, (Kansai University, J a p a n ) , J Japan Soc Heat Treatment, Vol 29, No 5, 1989, 258-263. In Japanese. Attention is drawn to the reason for retarded development of A1 alloys by the
50 MPR April 1991
i n g o t r o u t e , i.e. s e g r e g a t i o n of alloy elements. RS powders and PM have been u s e d to p r e p a r e alloys w i t h i m p r o v e d properties c o m p a r e d to cast and wrought materials. Densification procedures such as pseudo-HIP (e.g. Ceracon) are evaluated.
characterize the structure. Hardness, impact and wear resistance m e a s u r e m e n t s were made. The durability of an alloy Cu18.3% Sn-4.9% AI-2.2% Zn-0.55% Si was greater t h a n t h a t of previously used alloys for the application.
Copper
Iron and steel ............
- -
...............
-Z
......
- ----T
- ---- ........
P
LIQUID PHASE SINTERING OF BINARY Cu ALLOYS
SINTERING BEHAVIOUR AND STRENGTH OF Fe-Si-P COMPACTS
G.S. U p a d h y a y a a n d A. B h a t t a c h a r j e e , (Indian Institute of Technology, Kanpur, India), Int J Powder Metallurgy, Vol 27, No l, 23-27. The liquid p h a s e sintering of Cu base alloys with Ag, Si, Sn and Pb, has been investigated at two sintering t e m p e r a t u r e s for each alloy system. Alloy compositions were selected to give 5 wt% of the liquid p h a s e at e a c h s i n t e r i n g t e m p e r a t u r e . Densification, density, electrical conductivity, m i c r o h a r d n e s s and s t r e s s / s t r a i n r e s p o n s e w e r e e v a l u a t e d . The r e s u l t s are d i s c u s s e d in t e r m s of t h e e l e c t r o n i c s t r u c t u r e of t h e c o m p o n e n t elements in each alloy.
X. Qu et al, (Central South University of Technology, Changsha, Hunan, China), Int J Powder Metallurgy, Vol 27, No l, 9-13. Fe-Si-P compacts with 0.45% P and 0 to 6% Si were p r e p a r e d from Fe, Fe2P and Si p o w d e r s a n d s i n t e r e d in a r e d u c i n g a t m o s p h e r e at ll00°C. During sintering the P alloyed rapidly and e n h a n c e d the dissolving of the Si in the Fe. There was a reduction in solid volume and corresponding shrinkage of the compacts with little change in the relative density. It is suggested t h a t pore shrinkage due to diffusional mass t r a n s p o r t is offset by an i n c r e a s e in p o r e v o l u m e d u e to t h e K i r k e n d a l l effect. An i n c r e a s e in t h e tensile s t r e n g t h in alloys containing up to 4% Si was a t t r i b u t e d to solid solution s t r e n g t h e n i n g . Above 4% Si t h e r e was e m b r i t t l e m e n t of the alloys.
PRODUCTION OF D I S P E R S I O N S T R E N G T H E N E D Cu WITH HEAT RESISTANCE AND HIGH ELECTRICAL CONDUCTIVITY K. Nagata, M. Kumagai, (Sumitomo Light Metals, J a p a n ) , Sumitomo Light Metals Technical Reports, Vol 31, No 1, 1990, 97. In Japanese. A m e t h o d for the production of a Cu alloy, dispersion s t r e n g t h e n e d with A1203, is described. Cu powder alloyed with 0.05 to 3 vvt• p r o d u c e d by atomization. Cu powder surface was oxidized by heating in air at 300°C and mixed with the alloy powder. The powder mixture was c o n s o l i d a t e d a n d p r e s s e d i n t o a Cu container. Heating and hot forming oxidizes the Al and gives a fine dispersion of alumina in the Cu matrix. A 1 2 0 3
w
a
s
OPTIMIZATION OF COMPOSITION OF S I N T E R E D Cu-Sn-A1 ALLOYS L.M. Gurevich and A.K. Reimer, Metalloyed, Term, Obrab, Met, No 5, 1990, 2830. In Russian. The structure and mechanical properties of hot pressed Cu-17 to 20 wt% Sn-1 to 9% A1-0 to 4.4% Zn-0.1 to 1.0% Si w e r e d e t e r m i n e d in o r d e r to d e t e r m i n e t h e o p t i m u m composition of the alloy for use as the matrix in metal bonded d i a m o n d honing bars. X-ray diffraction, microscopy and m i c r o p r o b e analysis were used to
COMPOSITION MICROSTRUCTURE AND MECHANICAL PROPERTY RELATIONS IN S I N T E R E D STAINLESS STEEL A. Molinari et al, (University of Trento, Italy), Int J Powder Metallurgy, Vol 27, No 1, 15-21. Powder samples of 316L stainless steel containing additions of Cu (2, 4 and 9%) were compacted to 6.4 and 6.8 g/cm 3 and sintered at l l 8 0 ° C for 30 or 60 minutes in cracked ammonia. The microstructure was e x a m i n e d and tensile, bend and impact tests carried out. The m e a s u r e m e n t s and structure were correlated with the composition and process parameters. The i m p o r t a n c e of p o r o s i t y and nitrogen c o n t e n t in determination of properties was confirmed. Undissolved Cu in the alloys c a u s e s e m b r i t t l e m e n t . The r e s u l t s are reported to permit the optimization of the production of Cu alloyed 316L stainless steel.
STRUCTURES OF POWDERS AND COATINGS OF IRON-BASE EUTECTIC ALLOYS V.E. Oliker, Poroskovaya MetaUurgiya, No 7, 1990, 29 34. In Russian. Microscopy, X-ray diffraction and X ray