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Atomic scale laminated alloy structures produced by repeated pressing
PM
than T42. Structures are shown to contain MC and M6C carbides. The service life of T42 was reported to be longer than T15.
Mechanical alloying SYNTHESIS O F MOLYBDENUM DISILICIDE BY MECHANICAL ALLOYING
R.B. Schwarz et al (Los Alamos National Laboratory, California, USA), Materials Science and Engineering A, Vol A155, No 1-2, 1992, 75-83. It is reported that MoSi2, and other Mo silicides, can be synthesised by mechanical alloying w i t h a low O c o n t e n t w h e n processing is in high purity Ar. The MA powders could be pressed at 300°C lower than the normal temperature of 1800°C. The 0 content was stated to be 310 ppm by weight. The powders were characterized by X-ray diffraction and differential thermal analysis and the hot pressed compacts of e l e c t r o n m i c r o s c o p y . The m e c h a n i c a l properties were measured. SOLID STATE AMORPHIZATION OF IRON A N D COBALT BASED ALLOYS A N D THEIR MAGNETIC P R O P E R T I E S
S. Tanaka et al (Chobu University, Japan),
J Magnetism and Magnetic Materials Vol 112, No 1-3, 1992, 302-304. It is reported that Fe-Si-B powders do not amorphize on milling in vibratory or rotary ball mills and that Co-Fe-Si-B alloys become partially amorphous. The powders were characterized by differential thermal analysis.
Metal injection moulding I N J E C T I O N MOULDING OF M I X E D COARSE A N D FINE IRON POWDERS
D-W. Joo et al (Dong-A, University, Pusan, Korea), J Korean Inst of Metals, Vol 30,
No 12, 1992, 1467-1475. (In Korean). An investigation of MIM in which fine and coarse Fe powders were used is described. The green density is reported to increase to 97% with increase in the proportion of coarse powder. Debinding is said to be facilitated by the larger pores. The m a x i m u m proportion of coarse powder, which gave satisfactory results in MIM was 20%.
Oxide dispersion strenghened alloys RELATIONSHIP BETWEEN MICROSTRUCTURE A N D D E F O R M A T I O N DURING ROLLING OF ODS ALLOYS
J. Zbiral et al (Technical University, Vienna, Austria), Metall, Vol 47, No 2, 1993, 126128. (In German). The relationships between
48 MPR December 1993
LITERATURE
REVIEW
microstructure o f ODS a l l o y s a n d conditions of deformation by rolling were investigated. It is reported that deformation conditions were insufficient to characterize material behaviour. The existance of three deformation regions, loss of strength by dynamic grain growth, work hardening and an intermediate zone in which both occur, was demonstrated by examination of substructures. Evolution of microstructure, effects of c o m p o s i t i o n and d i s p e r s o i d content is shown for Fe-Cr, Ni-Cr and Cu.
Miscellaneous NEW MATERIALS BASED ON A M O R P H O U S POWDERS
P R O D U C T I O N A N D APPLICATION OF FINE ALLOY POWDERS
J.H. Reinshagen and G.W. J u c h a (Ametek Speciality Metal Products, Pennsylvania, USA). Applications, including injection m o u l d i n g , filters, e l e c t r o n i c s a n d as additives, of fine powders were described. Production methods for fine powders were reviewed. Attention was given to the use of very fine powders in press and sinter PM applications. COMPARISON O F ACTIVITY OF ZINC POWDERS P R O D U C E D BY D I F F E R E N T METHODS
M. Miskovicova, M. Fedorcakova (Slovak Academy of Sciences, Slovakia), Hutnicky L/sty, Vol 47, No 5, 1992,37-42. (In Slovak). The advantages of amorphous powder produced by rapid solidification and solid state amorphization are outlined. Applications of Al, Ti and Ni in aerospace and Fe, Nb, Ga and Cu in electrical uses are considered together with an indication of future trends.
X~ Song et al (General Research Inst of Mining and Metallurgy, Beijing, China). Uses of fine Zn powder in metallurgical a n d o t h e r i n d u s t r i e s was d i s c u s s e d . M e t h o d s of p r o d u c t i o n , a t o m i z a t i o n , electrodeposition and vapour phase deposition were considered. Powders were characterized by X-ray diffraction, scanning electron microscopy and surface analysis. The a c t i v i t i e s of t h e p o w d e r s w e r e compared as functions of the characteristics.
pM2TEC '93 The abstracts which follow are of papers which were presented at the 1993 International Conference on Powder Metallurgy and Particulate Materials which was held in Nashville, Tennessee, USA, 16-19 May.
PM'93 The abstracts which follow are of papers which were presented at the 1993 P o w d e r M e t a l l u r g y World C o n g r e s s which was held in Kyoto, Japan for 1215th July 1993.
Mechanical alloying Cermets and ceramics E F F E C T S OF CERAMIC PARTICLE SIZE A N D C O M P O S I T I O N ON ALUMINANICKEL C E R M E T S
S. Li and B.H. Kolster (University of Twente). An i n v e s t i g a t i o n of v a c c u u m h o t pressing of cermets consisting of Al203 particles coated with TiN and Ni was described. It was reported that with 1020 pm Al203 powder higher densities and mechanical properties were attained than with 40-50 ~tm Al203. The densities and mechanical properties except hardness decreased with increase in A1203 content. The results were explained and discussed.
Fine powders P R O D U C T I O N OF VERY FINE HYDROMETALLURGICAL POWDERS
B.H. Rosof (Sherritt Gordon Ltd, Fort Saskatchewan, Alberta, Canada). Methods of production, types of powder and applications of Ni, Co and Cu powders were described. The commercial importance of powders less than 10 ~tm in size in the PM and other industries was discussed.
ATOMIC SCALE LAMINATED ALLOY S T R U C T U R E S P R O D U C E D BY REPEATED PRESSING
P.H. Shingu, I~N. Ishihara (Kyoto University, Kyoto, Japan). It was reported that when thin metal foils or layers of particles are pressed, cut, stacked and repressed to form a multiple layer structure nanometer sized grains are formed. Details of phase boundaries and physical properties were described. D E V E L O P M E N T OF A HIGH S P E E D MECHANICAL ALLOYING SYSTEM
T. Azizawa, J. Kihara (University of Tokyo, Tokyo, Japan). A new type of MA system was described. The objectives were to reduce process time and c o n t a m i n t i o n . Si-A1 was used to d e m o n s t r a t e t h e e f f e c t i v e n e s s of t h e system. The m e c h a n i s m s of MA were discussed. DETAILED ANALYSIS OF PHASE FORMATION D U R I N G MECHANICAL ALLOYING
C. Rock et al (University of Kentucky, Lexington, Kentucky, USA).
than T42. Structures are shown to contain MC and M6C carbides. The service life of T42 was reported to be longer than T15.
Mechanical alloying SYNTHESIS O F MOLYBDENUM DISILICIDE BY MECHANICAL ALLOYING
R.B. Schwarz et al (Los Alamos National Laboratory, California, USA), Materials Science and Engineering A, Vol A155, No 1-2, 1992, 75-83. It is reported that MoSi2, and other Mo silicides, can be synthesised by mechanical alloying w i t h a low O c o n t e n t w h e n processing is in high purity Ar. The MA powders could be pressed at 300°C lower than the normal temperature of 1800°C. The 0 content was stated to be 310 ppm by weight. The powders were characterized by X-ray diffraction and differential thermal analysis and the hot pressed compacts of e l e c t r o n m i c r o s c o p y . The m e c h a n i c a l properties were measured. SOLID STATE AMORPHIZATION OF IRON A N D COBALT BASED ALLOYS A N D THEIR MAGNETIC P R O P E R T I E S
S. Tanaka et al (Chobu University, Japan),
J Magnetism and Magnetic Materials Vol 112, No 1-3, 1992, 302-304. It is reported that Fe-Si-B powders do not amorphize on milling in vibratory or rotary ball mills and that Co-Fe-Si-B alloys become partially amorphous. The powders were characterized by differential thermal analysis.
Metal injection moulding I N J E C T I O N MOULDING OF M I X E D COARSE A N D FINE IRON POWDERS
D-W. Joo et al (Dong-A, University, Pusan, Korea), J Korean Inst of Metals, Vol 30,
No 12, 1992, 1467-1475. (In Korean). An investigation of MIM in which fine and coarse Fe powders were used is described. The green density is reported to increase to 97% with increase in the proportion of coarse powder. Debinding is said to be facilitated by the larger pores. The m a x i m u m proportion of coarse powder, which gave satisfactory results in MIM was 20%.
Oxide dispersion strenghened alloys RELATIONSHIP BETWEEN MICROSTRUCTURE A N D D E F O R M A T I O N DURING ROLLING OF ODS ALLOYS
J. Zbiral et al (Technical University, Vienna, Austria), Metall, Vol 47, No 2, 1993, 126128. (In German). The relationships between
48 MPR December 1993
LITERATURE
REVIEW
microstructure o f ODS a l l o y s a n d conditions of deformation by rolling were investigated. It is reported that deformation conditions were insufficient to characterize material behaviour. The existance of three deformation regions, loss of strength by dynamic grain growth, work hardening and an intermediate zone in which both occur, was demonstrated by examination of substructures. Evolution of microstructure, effects of c o m p o s i t i o n and d i s p e r s o i d content is shown for Fe-Cr, Ni-Cr and Cu.
Miscellaneous NEW MATERIALS BASED ON A M O R P H O U S POWDERS
P R O D U C T I O N A N D APPLICATION OF FINE ALLOY POWDERS
J.H. Reinshagen and G.W. J u c h a (Ametek Speciality Metal Products, Pennsylvania, USA). Applications, including injection m o u l d i n g , filters, e l e c t r o n i c s a n d as additives, of fine powders were described. Production methods for fine powders were reviewed. Attention was given to the use of very fine powders in press and sinter PM applications. COMPARISON O F ACTIVITY OF ZINC POWDERS P R O D U C E D BY D I F F E R E N T METHODS
M. Miskovicova, M. Fedorcakova (Slovak Academy of Sciences, Slovakia), Hutnicky L/sty, Vol 47, No 5, 1992,37-42. (In Slovak). The advantages of amorphous powder produced by rapid solidification and solid state amorphization are outlined. Applications of Al, Ti and Ni in aerospace and Fe, Nb, Ga and Cu in electrical uses are considered together with an indication of future trends.
X~ Song et al (General Research Inst of Mining and Metallurgy, Beijing, China). Uses of fine Zn powder in metallurgical a n d o t h e r i n d u s t r i e s was d i s c u s s e d . M e t h o d s of p r o d u c t i o n , a t o m i z a t i o n , electrodeposition and vapour phase deposition were considered. Powders were characterized by X-ray diffraction, scanning electron microscopy and surface analysis. The a c t i v i t i e s of t h e p o w d e r s w e r e compared as functions of the characteristics.
pM2TEC '93 The abstracts which follow are of papers which were presented at the 1993 International Conference on Powder Metallurgy and Particulate Materials which was held in Nashville, Tennessee, USA, 16-19 May.
PM'93 The abstracts which follow are of papers which were presented at the 1993 P o w d e r M e t a l l u r g y World C o n g r e s s which was held in Kyoto, Japan for 1215th July 1993.
Mechanical alloying Cermets and ceramics E F F E C T S OF CERAMIC PARTICLE SIZE A N D C O M P O S I T I O N ON ALUMINANICKEL C E R M E T S
S. Li and B.H. Kolster (University of Twente). An i n v e s t i g a t i o n of v a c c u u m h o t pressing of cermets consisting of Al203 particles coated with TiN and Ni was described. It was reported that with 1020 pm Al203 powder higher densities and mechanical properties were attained than with 40-50 ~tm Al203. The densities and mechanical properties except hardness decreased with increase in A1203 content. The results were explained and discussed.
Fine powders P R O D U C T I O N OF VERY FINE HYDROMETALLURGICAL POWDERS
B.H. Rosof (Sherritt Gordon Ltd, Fort Saskatchewan, Alberta, Canada). Methods of production, types of powder and applications of Ni, Co and Cu powders were described. The commercial importance of powders less than 10 ~tm in size in the PM and other industries was discussed.
ATOMIC SCALE LAMINATED ALLOY S T R U C T U R E S P R O D U C E D BY REPEATED PRESSING
P.H. Shingu, I~N. Ishihara (Kyoto University, Kyoto, Japan). It was reported that when thin metal foils or layers of particles are pressed, cut, stacked and repressed to form a multiple layer structure nanometer sized grains are formed. Details of phase boundaries and physical properties were described. D E V E L O P M E N T OF A HIGH S P E E D MECHANICAL ALLOYING SYSTEM
T. Azizawa, J. Kihara (University of Tokyo, Tokyo, Japan). A new type of MA system was described. The objectives were to reduce process time and c o n t a m i n t i o n . Si-A1 was used to d e m o n s t r a t e t h e e f f e c t i v e n e s s of t h e system. The m e c h a n i s m s of MA were discussed. DETAILED ANALYSIS OF PHASE FORMATION D U R I N G MECHANICAL ALLOYING
C. Rock et al (University of Kentucky, Lexington, Kentucky, USA).