- Email: [email protected]
Amorphization during mechanical alloying (MA) of metal powders
MECHANICAL P R O P E R T I E S OF PM BD O P E D Ni A L U M I N I D E
Metal Injection Moulding ................
E-H. Yoon, et al, (Inha University, Inchon, Korea), J. Korean Inst. of Metals, Vol 28, No 10, 1990, 887-894. In Korean. The r o l e of B in i m p r o v i n g t h e mechanical properties of Ni3AI (24 to 25%A1) was examined. Compacts were produced either by reactive sintering or by HIP of elemental powders. B acted to suppress intergranular embrittlement and the fracture changed from intergranular to transgranular, in presence of B which also increased the strength of the alloy.
APPLICATION OF LIQUID PHASE S I N T E R I N G IN P R O D U C T I O N OF INTERMETALLIC C O M P O U N D S
L.I. Kivalo, N.F. Grigorenko, Adgez. Rasplay. Paika Mater, No 23, 1990, 61-64. In Russian. Liquid phase sintering and interphase reactions in Fe-Ti alloys were studied. Wetting of Fe and Ti substrates by Fe-Ti eutectic was determined. Structures of phases and mechanisms of liquid phase sintering are discussed.
Mechanical Alloying DEVELOPMENT OF OXIDE DISPERSION STRENGTHENED (ODS) ALLOYS BY MECHANICAL ALLOYING
(MA) M. Fujiwara, T. Nishida, (Kobe Steel, Japan), Kobelco Technology Review, No 9, 1990, 43-46. Yttrium oxide, Ti and Mo powders have been added to 12%Cr powder steels which w e r e t h e n s u b j e c t e d to MA. A f t e r consolidation, the elevated temperature mechanical properties were measured. The s t r e n g t h was i n c r e a s e d and this was attributed to a combination of dispersion strengthening and solid solution hardening. AMORPHIZATION DURING MECHANICAL ALLOYING ( M A ) O F METAL POWDERS
C.C. Koch, (North Carolina State University, USA), Reactive Solids, Vol 8, No 3-4, 1990, 283-297. The reactions which lead to amorphization during MA are reviewed. A distinction is made between MA processes where material transfer occurs between particles and mechanical milling where an intermediate phase is formed and which then transforms to the amorphous state. Thermodynamic and kinetic criteria are outlined. Recent e x p e r i m e n t a l d a t a is given and the i m p l i c a t i o n s discussed. Examples of intermetallic compounds of Nb with Sn, Ge, A1 and Zr are considered.
76 MPR May 1991
Ill l
USE OF METAL I N J E C T I O N MOULDING ( M I M ) - - D E S I G N FOR S I N T E R E D METAL PARTS
W. Michaeli, R. Bielzer, Ing. Werkstoffe, Vol 2, No 6, 1990, 48-52. In German. The principles of MIM are outlined. Physical properties, thermal conductivity, specific heat and viscosity are discussed with respect to the debinding stage of MIM and the prediction of process variables. Design of dies is discussed and the need for large entry ports in the dies is emphasized. METAL I N J E C T I O N MOULDING ( M I M ) OF COPPER POWDER
Y. Kaneko, K. Ameyama, (Ritsumeikan University, J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 3, 1990, 352-353. In Japanese. An investigation into the moulding of Cu powder has been carried out in order to optimize the process conditions. Formability and sinterability were investigated. Physical properties of the metal powder/binder mixture are discussed. The microstructures of sintered metals were examined and it was deduced that high densities had been attained. P R E S E N T STATE OF METAL I N J E C T I O N MOULDING
T. Bokorova, M. Miscovicova, Pokroky Praskove Metalurgie, No 3, 1990, 54-66. In Polish. The fundamental principles and characteristics of metal injection moulding are reviewed. The process is shown to be cost effective for the production of small, precision components, in special metals and alloys for automotive, aerospace and electronic applications.
HIP AND PM IN PRODUCTION OF GAS AND STEAM TURBINE PARTS
R. Ekbom, (ASEA Brown Boveri, Sweden), Materials Design, Vol I l, No 1, 1990, 37-42. The use of PM and HIP in the production of turbine parts is described and it is shown that this results in materials with improved properties compared with forgings. Examples are given. D E S I G N A N D PRODUCTION OF LONG LIFE PM BEARINGS
S.C. Lira, W.K.H. Seah, (National University of Singapore), J. Materials Processing Technology, Vol 23, No 2, 1990, 97-105. Attention is drawn to the fact that the life of a self l u b r i c a t i n g b e a r i n g is determined by oil retention in the pores. An investigation into ways of increasing lubricant retention, by increase in porosity without reduction in strength of the alloy is described. The use of a duplex bearing, in which a highly porous rubbing surface is supported by a stronger core, is outlined. Importance is attached to the design of bearings and dies.
MISCELLANEOUS THE P R E S E N T C O N D I T I O N OF METAL POWDER PRODUCTION A N D USE IN THE USSR
O.S. N i c h i p o r e n k o , Poroshkavaya Metallurgiya, No 9, 1990, 1-11. In Russian.
PM Parts ' I!
Germany), Ind. -Anz., Vol 112, No 57-58, July 1990, 18-20. In German. The use of p o w d e r forging, which combines sintering with precision forging, to produce strong, porosity free parts is discussed. The process can be used to make parts with different alloys in different zones such as an alloy steel in the case and a carbon steel in the core of a gear.
"NHr
It'
P R O D U C T I O N OF A BIMETALLIC CYLINDER FOR PLASTICS I N J E C T I O N MOULDING MACHINE BY HOT ISOSTATIC P R E S S I N G ( H I P )
The production and application of metal powders in the USSR are reviewed. The main powder production processes in use are s h o w n to be spraying, c h e m i c a l r e d u c t i o n and electrolysis. The m o s t c o m m o n l y m a n u f a c t u r e d m a t e r i a l s are iron and copper based alloys.
S. Nakamura, et al, (Kobe Steel, Japan),
Kobelco Technology Review, No 9, 1990, 2428. HIP bonding has been used to fabricate bi-metallic cylinders for plastics injection moulding machines. The corrosion and wear resistance are said to be greater than those of conventional nitrided steels or centrifugally cast alloys. PRODUCTION OF DUPLEX POWDER F O R G E D PARTS
W. KSnig, G. RSber,
(RWTH, Aachen,
POWDER METALLURGY IMPROVES PERFORMANCE
M. Hunt, Materials Engineering, Vol 107, No 9, 1990, 16-19. Recent advances in powder production and consolidation processes are reviewed with respect to aerospace applications requiring light weight and high stiffness in airframe components, and high temperature resistance in engine parts. Uses of A1, Mg, Ti, Be and superalloys are outlined.
Metal Injection Moulding ................
E-H. Yoon, et al, (Inha University, Inchon, Korea), J. Korean Inst. of Metals, Vol 28, No 10, 1990, 887-894. In Korean. The r o l e of B in i m p r o v i n g t h e mechanical properties of Ni3AI (24 to 25%A1) was examined. Compacts were produced either by reactive sintering or by HIP of elemental powders. B acted to suppress intergranular embrittlement and the fracture changed from intergranular to transgranular, in presence of B which also increased the strength of the alloy.
APPLICATION OF LIQUID PHASE S I N T E R I N G IN P R O D U C T I O N OF INTERMETALLIC C O M P O U N D S
L.I. Kivalo, N.F. Grigorenko, Adgez. Rasplay. Paika Mater, No 23, 1990, 61-64. In Russian. Liquid phase sintering and interphase reactions in Fe-Ti alloys were studied. Wetting of Fe and Ti substrates by Fe-Ti eutectic was determined. Structures of phases and mechanisms of liquid phase sintering are discussed.
Mechanical Alloying DEVELOPMENT OF OXIDE DISPERSION STRENGTHENED (ODS) ALLOYS BY MECHANICAL ALLOYING
(MA) M. Fujiwara, T. Nishida, (Kobe Steel, Japan), Kobelco Technology Review, No 9, 1990, 43-46. Yttrium oxide, Ti and Mo powders have been added to 12%Cr powder steels which w e r e t h e n s u b j e c t e d to MA. A f t e r consolidation, the elevated temperature mechanical properties were measured. The s t r e n g t h was i n c r e a s e d and this was attributed to a combination of dispersion strengthening and solid solution hardening. AMORPHIZATION DURING MECHANICAL ALLOYING ( M A ) O F METAL POWDERS
C.C. Koch, (North Carolina State University, USA), Reactive Solids, Vol 8, No 3-4, 1990, 283-297. The reactions which lead to amorphization during MA are reviewed. A distinction is made between MA processes where material transfer occurs between particles and mechanical milling where an intermediate phase is formed and which then transforms to the amorphous state. Thermodynamic and kinetic criteria are outlined. Recent e x p e r i m e n t a l d a t a is given and the i m p l i c a t i o n s discussed. Examples of intermetallic compounds of Nb with Sn, Ge, A1 and Zr are considered.
76 MPR May 1991
Ill l
USE OF METAL I N J E C T I O N MOULDING ( M I M ) - - D E S I G N FOR S I N T E R E D METAL PARTS
W. Michaeli, R. Bielzer, Ing. Werkstoffe, Vol 2, No 6, 1990, 48-52. In German. The principles of MIM are outlined. Physical properties, thermal conductivity, specific heat and viscosity are discussed with respect to the debinding stage of MIM and the prediction of process variables. Design of dies is discussed and the need for large entry ports in the dies is emphasized. METAL I N J E C T I O N MOULDING ( M I M ) OF COPPER POWDER
Y. Kaneko, K. Ameyama, (Ritsumeikan University, J a p a n ) , J. Japan Inst. of Metals, Vol 54, No 3, 1990, 352-353. In Japanese. An investigation into the moulding of Cu powder has been carried out in order to optimize the process conditions. Formability and sinterability were investigated. Physical properties of the metal powder/binder mixture are discussed. The microstructures of sintered metals were examined and it was deduced that high densities had been attained. P R E S E N T STATE OF METAL I N J E C T I O N MOULDING
T. Bokorova, M. Miscovicova, Pokroky Praskove Metalurgie, No 3, 1990, 54-66. In Polish. The fundamental principles and characteristics of metal injection moulding are reviewed. The process is shown to be cost effective for the production of small, precision components, in special metals and alloys for automotive, aerospace and electronic applications.
HIP AND PM IN PRODUCTION OF GAS AND STEAM TURBINE PARTS
R. Ekbom, (ASEA Brown Boveri, Sweden), Materials Design, Vol I l, No 1, 1990, 37-42. The use of PM and HIP in the production of turbine parts is described and it is shown that this results in materials with improved properties compared with forgings. Examples are given. D E S I G N A N D PRODUCTION OF LONG LIFE PM BEARINGS
S.C. Lira, W.K.H. Seah, (National University of Singapore), J. Materials Processing Technology, Vol 23, No 2, 1990, 97-105. Attention is drawn to the fact that the life of a self l u b r i c a t i n g b e a r i n g is determined by oil retention in the pores. An investigation into ways of increasing lubricant retention, by increase in porosity without reduction in strength of the alloy is described. The use of a duplex bearing, in which a highly porous rubbing surface is supported by a stronger core, is outlined. Importance is attached to the design of bearings and dies.
MISCELLANEOUS THE P R E S E N T C O N D I T I O N OF METAL POWDER PRODUCTION A N D USE IN THE USSR
O.S. N i c h i p o r e n k o , Poroshkavaya Metallurgiya, No 9, 1990, 1-11. In Russian.
PM Parts ' I!
Germany), Ind. -Anz., Vol 112, No 57-58, July 1990, 18-20. In German. The use of p o w d e r forging, which combines sintering with precision forging, to produce strong, porosity free parts is discussed. The process can be used to make parts with different alloys in different zones such as an alloy steel in the case and a carbon steel in the core of a gear.
"NHr
It'
P R O D U C T I O N OF A BIMETALLIC CYLINDER FOR PLASTICS I N J E C T I O N MOULDING MACHINE BY HOT ISOSTATIC P R E S S I N G ( H I P )
The production and application of metal powders in the USSR are reviewed. The main powder production processes in use are s h o w n to be spraying, c h e m i c a l r e d u c t i o n and electrolysis. The m o s t c o m m o n l y m a n u f a c t u r e d m a t e r i a l s are iron and copper based alloys.
S. Nakamura, et al, (Kobe Steel, Japan),
Kobelco Technology Review, No 9, 1990, 2428. HIP bonding has been used to fabricate bi-metallic cylinders for plastics injection moulding machines. The corrosion and wear resistance are said to be greater than those of conventional nitrided steels or centrifugally cast alloys. PRODUCTION OF DUPLEX POWDER F O R G E D PARTS
W. KSnig, G. RSber,
(RWTH, Aachen,
POWDER METALLURGY IMPROVES PERFORMANCE
M. Hunt, Materials Engineering, Vol 107, No 9, 1990, 16-19. Recent advances in powder production and consolidation processes are reviewed with respect to aerospace applications requiring light weight and high stiffness in airframe components, and high temperature resistance in engine parts. Uses of A1, Mg, Ti, Be and superalloys are outlined.