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Characteristics of electron beam weldable molybdenum and its alloys with rhenium
FORMATION OF METASTABLE ALUMINIUM ALLOYS BY MECHANICAL ALLOYING
M. Ropy et al (Indian Inst. of Technology, Kanpur, India) J. Materials Science Letters, Vol 11, No 12, 1992-, 858-861. The use of mechanical alloying to produce quasi-crystalline or amorphous powders of A1-20at%Mn-30%Ge, A1-20%Mn30%Ge and A1-20%Mn-20%Si-10%Ge is r e por t e d . The c h a r a c t e r i s t i c s of th e powders are compared with those of powders produced by other means. High transition temperatures of 617°C and weak ferromagnetic behaviour are reported. BEHAVIOUR OF PM ALUMINIUM A N D ALUMINIUM-COPPER ALLOY RINGS IN RADIAL C R U S H I N G T E S T S
T.S. Rao, I~S. Pandey, (Regional Engineering College, Tiruchipali, India), Powder
Metallurgy Science a n d
Technology.
Vol 4, No 2, 1993, 49-56. An investigation of the radial crushing strength of rings fabricated from A1-(0 to 4)wt%Cu is described. The variables studied were ring geometry, alloy composition and density level. It is reported that, other things being equal, the crushing strength is independent of ring geometry. The crushing strength is increased by Cu content and reduced by increased porosity. DOUBLE MECHANICAL ALLOYING O F ALUMINIUM-IRON-MANGANESE ALLOYS
L. Delaey et al, (Katholic University, Leuven, Belgium), Materials Science and Engineering A, Vol A157, No 1, 1992, 79-88. It is reported that MA has been used to produce AI-5wt%Fe-4%Mn alloy powders. The Al alloy is s t a b i l i z e d by i n e r t dispersions and strengthened by intermetallics. A MA-heat treatment-MA cycle was used with the intermetallics forming d u r i n g h e a t t r e a t m e n t . The second MA stage is used to refine the structure. The intermetallic compounds are described. The mechanical properties are evaluated and Young's modulus is shown to be a function of the volume fraction of intermetallics present. A STUDY OF THE E F F E C T S OF IRON A N D SILICON O N STRUCTURE A N D P R O P E R T I E S OF A T O M I Z E D ALUMINIUM-LITHIUM POWDER ALLOYS
F.H. Samuel et al (University of Quebec Chicoutimi, Canada), J. Materials Science, Vol 27, No 18, 1992, 4917-4926. The effects of additions of Fe and Si to a range of A1-Li alloy powders, produced by centrifugal atomization, were investigated. The AI-Si eutectic point is displaced to less than 4%Si by addition of 3%Li and the eutectic consists of A1 and A1-Li-Si phases
58 MPR May 1994
which are described. In A1-2.5%Li-l.3%Fe precipitates of 5'A13Li, AlaFe and Al0Fe are present. The volume fraction of AlaFe d i s p e r s o i d s is not affected by grain boundaries. SUPERPLASTIC D E F O R M A T I O N IN MECHANICALLY ALLOYED ALUMINIUM ALLOY
tC Higashi et al (University of Osaka Prefecture, Osaka, Japan) J. Japan Soc. Powder and Powder Metallurgy, Vol 40, No 3, 1993, 337-340. (In English). The tensile properties of A1-4wt%Mg1,.5%LI-1.2%C-O.4%O, which had been prepared from MA powder by extrusion and thermomechanical processing into 1 mm sheet, were investigated at strain rates between 10-3 and 200 per sec at 425°C to 575°C. S u p e r p l a s t i c i t y was observed, with elongations of 200% at a constant strain rate of 20 per sec. This is attributed to a grain boundary sliding mechanism accommodated by dislocation climb or glide controlled by grain boundary diffusion.
Copper E F F E C T S O F TIN CONTENT IN BRONZES USING COMPUTERIZED STATISTICAL TECHNIQUES
G. F. Castedo et al (Metallurgical Research Centre, Havana, Cuba), Powder Metallurgy Science and Technology. Vol 4, No 2, 1993, 24-30. The large n u m b e r of p a r a m e t e r s involved in r e s e a r c h into PM p a r t s products is discussed with regard to the use of statistics. The application of various computer programmes to the study of PM processes, such as the production of tinbronzes, is discussed.
Iron and Steel M I C R O S T R U C T U R E AND MECHANICAL P R O P E R T I E S O F S I N T E R E D IRON
H. Danninger et al (Technological University, Vienna, Austria) Powder Metall. Int.,
Vol 25, No 4, 1993, 170-173 and Powder Metall. Int., Vol 25 No 5, 1993, 219-223. A new concept concerning structure property relationships in sintered Fe is described. Variations in properties due to changes in process variables are outlined. Microstructures are taken from fracture surfaces of specimens impacted at 77K and from fatigue test fractures. Interconnected p o r o s i t y c o u l d be determined from impact fracture surfaces. Actual load bearing cross section was determined and correlated with properties. P R O D U C T I O N OF IRON B A S E D POWDER METALLURGY S H E E T
LS. Shmelev, V.I/: Sorokin, Stal', No 3,
1992, 78-79. (In Russian). The characteristics of rolled porous and n o n - p o r o u s Fe b a s e m a t e r i a l s a r e discussed. The process and the factors involved in the production of steel sheet from powders are outlined and aspects of the machinery used are described. Additives to induce porosity are noted. I N F L U E N C E O F LIQUID P H A S E S I N T E R I N G C O N D I T I O N S ON P R O P E R T I E S O F IRON-BORN ALLOYS
N. Selecka, E. Dudrova, (Ustav Materialoveho Vyskumu SAV, Kosice, Slovakia) Pokroky Praskove Metalurgie, No 2, 1993, 44-57. (In Czech). The effects of 0 to 0.6%B, added as ferroboron, and s i n t e r i n g c o n d i t i o n s on densification, structure and hardness of Fe base c o m p a c t s was i n v e s t i g a t e d . Maximum density was obtained on s i n t e r i n g at 1250°C w i t h 0.6%B. M e c h a n i s m s of d e n s i f i c a t i o n are identified as dissolution and d i s i n t e g r a t i o n of Fe p a r t i c l e s a n d formation of a eutectic in presence of B. Fracture characteristics are reported to be m i x e d an d it is s u g g e s t e d t h a t h i g h e r f r a c t u r e t o u g h n e s s c o u l d be obtained in Fe-B alloys.
Molybdenum CHARACTERISTICS O F E L E C T R O N B E A M WELDABLE MOLYBDENUM A N D ITS ALLOYS WITH R H E N I U M
F. Morito. J. of Metals, Vol 45, No 6, 1993, 54-58. The electron beam (EB) weldability of PM Mo and Mo-Re alloys is compared with t h a t of c a s t / w r o u g h t m a t e r i a l s . By processing the PM materials, at all stages, to minimize O content sound EB welds could be produced. Doping with C and postweld heat treatment are reported to restore strength and to minimize embrittlement and enhance ductility. This is attributed to improved grain boundary cohesion. It is concluded the EB welding of PM materials has good potential for high performance parts production and other structural applications.
Niobium SYNTHESIS O F M E T A S T A B L E P H A S E S IN NIOBIUM-ALUMINIUM ALLOYS BY MECHANICAL ALLOYING
F.H. Froes et al (University of Idaho, Moscow, Idaho, USA), Scripta Metall. Mater., Vol 27, No 4, 1992, 475-480. It is reported that NbA1a and amorphous phases had been produced by MA of pure e l e m e n t a l powders. It is shown t h a t p r o d u c t i o n of t h e c o m p o u n d a n d a m o r p h o u s p h a s e s r e q u i r e d 15 a nd 40 h o u r s r e s p e c t i v e l y . S o m e s o l i d solubility of Nb in A1 is also reported.
M. Ropy et al (Indian Inst. of Technology, Kanpur, India) J. Materials Science Letters, Vol 11, No 12, 1992-, 858-861. The use of mechanical alloying to produce quasi-crystalline or amorphous powders of A1-20at%Mn-30%Ge, A1-20%Mn30%Ge and A1-20%Mn-20%Si-10%Ge is r e por t e d . The c h a r a c t e r i s t i c s of th e powders are compared with those of powders produced by other means. High transition temperatures of 617°C and weak ferromagnetic behaviour are reported. BEHAVIOUR OF PM ALUMINIUM A N D ALUMINIUM-COPPER ALLOY RINGS IN RADIAL C R U S H I N G T E S T S
T.S. Rao, I~S. Pandey, (Regional Engineering College, Tiruchipali, India), Powder
Metallurgy Science a n d
Technology.
Vol 4, No 2, 1993, 49-56. An investigation of the radial crushing strength of rings fabricated from A1-(0 to 4)wt%Cu is described. The variables studied were ring geometry, alloy composition and density level. It is reported that, other things being equal, the crushing strength is independent of ring geometry. The crushing strength is increased by Cu content and reduced by increased porosity. DOUBLE MECHANICAL ALLOYING O F ALUMINIUM-IRON-MANGANESE ALLOYS
L. Delaey et al, (Katholic University, Leuven, Belgium), Materials Science and Engineering A, Vol A157, No 1, 1992, 79-88. It is reported that MA has been used to produce AI-5wt%Fe-4%Mn alloy powders. The Al alloy is s t a b i l i z e d by i n e r t dispersions and strengthened by intermetallics. A MA-heat treatment-MA cycle was used with the intermetallics forming d u r i n g h e a t t r e a t m e n t . The second MA stage is used to refine the structure. The intermetallic compounds are described. The mechanical properties are evaluated and Young's modulus is shown to be a function of the volume fraction of intermetallics present. A STUDY OF THE E F F E C T S OF IRON A N D SILICON O N STRUCTURE A N D P R O P E R T I E S OF A T O M I Z E D ALUMINIUM-LITHIUM POWDER ALLOYS
F.H. Samuel et al (University of Quebec Chicoutimi, Canada), J. Materials Science, Vol 27, No 18, 1992, 4917-4926. The effects of additions of Fe and Si to a range of A1-Li alloy powders, produced by centrifugal atomization, were investigated. The AI-Si eutectic point is displaced to less than 4%Si by addition of 3%Li and the eutectic consists of A1 and A1-Li-Si phases
58 MPR May 1994
which are described. In A1-2.5%Li-l.3%Fe precipitates of 5'A13Li, AlaFe and Al0Fe are present. The volume fraction of AlaFe d i s p e r s o i d s is not affected by grain boundaries. SUPERPLASTIC D E F O R M A T I O N IN MECHANICALLY ALLOYED ALUMINIUM ALLOY
tC Higashi et al (University of Osaka Prefecture, Osaka, Japan) J. Japan Soc. Powder and Powder Metallurgy, Vol 40, No 3, 1993, 337-340. (In English). The tensile properties of A1-4wt%Mg1,.5%LI-1.2%C-O.4%O, which had been prepared from MA powder by extrusion and thermomechanical processing into 1 mm sheet, were investigated at strain rates between 10-3 and 200 per sec at 425°C to 575°C. S u p e r p l a s t i c i t y was observed, with elongations of 200% at a constant strain rate of 20 per sec. This is attributed to a grain boundary sliding mechanism accommodated by dislocation climb or glide controlled by grain boundary diffusion.
Copper E F F E C T S O F TIN CONTENT IN BRONZES USING COMPUTERIZED STATISTICAL TECHNIQUES
G. F. Castedo et al (Metallurgical Research Centre, Havana, Cuba), Powder Metallurgy Science and Technology. Vol 4, No 2, 1993, 24-30. The large n u m b e r of p a r a m e t e r s involved in r e s e a r c h into PM p a r t s products is discussed with regard to the use of statistics. The application of various computer programmes to the study of PM processes, such as the production of tinbronzes, is discussed.
Iron and Steel M I C R O S T R U C T U R E AND MECHANICAL P R O P E R T I E S O F S I N T E R E D IRON
H. Danninger et al (Technological University, Vienna, Austria) Powder Metall. Int.,
Vol 25, No 4, 1993, 170-173 and Powder Metall. Int., Vol 25 No 5, 1993, 219-223. A new concept concerning structure property relationships in sintered Fe is described. Variations in properties due to changes in process variables are outlined. Microstructures are taken from fracture surfaces of specimens impacted at 77K and from fatigue test fractures. Interconnected p o r o s i t y c o u l d be determined from impact fracture surfaces. Actual load bearing cross section was determined and correlated with properties. P R O D U C T I O N OF IRON B A S E D POWDER METALLURGY S H E E T
LS. Shmelev, V.I/: Sorokin, Stal', No 3,
1992, 78-79. (In Russian). The characteristics of rolled porous and n o n - p o r o u s Fe b a s e m a t e r i a l s a r e discussed. The process and the factors involved in the production of steel sheet from powders are outlined and aspects of the machinery used are described. Additives to induce porosity are noted. I N F L U E N C E O F LIQUID P H A S E S I N T E R I N G C O N D I T I O N S ON P R O P E R T I E S O F IRON-BORN ALLOYS
N. Selecka, E. Dudrova, (Ustav Materialoveho Vyskumu SAV, Kosice, Slovakia) Pokroky Praskove Metalurgie, No 2, 1993, 44-57. (In Czech). The effects of 0 to 0.6%B, added as ferroboron, and s i n t e r i n g c o n d i t i o n s on densification, structure and hardness of Fe base c o m p a c t s was i n v e s t i g a t e d . Maximum density was obtained on s i n t e r i n g at 1250°C w i t h 0.6%B. M e c h a n i s m s of d e n s i f i c a t i o n are identified as dissolution and d i s i n t e g r a t i o n of Fe p a r t i c l e s a n d formation of a eutectic in presence of B. Fracture characteristics are reported to be m i x e d an d it is s u g g e s t e d t h a t h i g h e r f r a c t u r e t o u g h n e s s c o u l d be obtained in Fe-B alloys.
Molybdenum CHARACTERISTICS O F E L E C T R O N B E A M WELDABLE MOLYBDENUM A N D ITS ALLOYS WITH R H E N I U M
F. Morito. J. of Metals, Vol 45, No 6, 1993, 54-58. The electron beam (EB) weldability of PM Mo and Mo-Re alloys is compared with t h a t of c a s t / w r o u g h t m a t e r i a l s . By processing the PM materials, at all stages, to minimize O content sound EB welds could be produced. Doping with C and postweld heat treatment are reported to restore strength and to minimize embrittlement and enhance ductility. This is attributed to improved grain boundary cohesion. It is concluded the EB welding of PM materials has good potential for high performance parts production and other structural applications.
Niobium SYNTHESIS O F M E T A S T A B L E P H A S E S IN NIOBIUM-ALUMINIUM ALLOYS BY MECHANICAL ALLOYING
F.H. Froes et al (University of Idaho, Moscow, Idaho, USA), Scripta Metall. Mater., Vol 27, No 4, 1992, 475-480. It is reported that NbA1a and amorphous phases had been produced by MA of pure e l e m e n t a l powders. It is shown t h a t p r o d u c t i o n of t h e c o m p o u n d a n d a m o r p h o u s p h a s e s r e q u i r e d 15 a nd 40 h o u r s r e s p e c t i v e l y . S o m e s o l i d solubility of Nb in A1 is also reported.