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Characterization of titanium aluminide powder made by plasma rotation electrode process (PREP)
PM
NOVEL MANUFACTURE OF RAPIDLY SOLIDIFIED ( R S ) PARTICLES BY MODIFIED MELT EXTRACTION G. S t e p h a n i (Frauhofer-Inst) ffir Angew a n d t e Materials-Forschung, Germany). A m e t h o d for p r o d u c t i o n of s h o r t metallic fibres, based on solidification on a notched edge of a rotating disc and a novel m e l t e x t r a c t i o n t e c h n i q u e w a s reported to enable cooling rates of I0n°C/ sec to be attained. The formation of metal matrix c o m p o s i t e s of SiC in a rapidly quenched matrix was reported.
PM properties MECHANICAL PROPERTIES OF NANOCRYSTALS PRODUCED FROM ULTRAFINE NICKEL POWDERS L.I. Trusov et al (Ultram International Inc,
USA). The mechanical properties of specimens formed from nanocrystalline Ni powder, 65 nm in size, were investigated. Powders were produced by inert gas evaporation/ condensation techniques and consolidated by isostatic pressure at 500°C and 4.4 GPa. At a density of 94 to 96% the vickers h a r d n e s s was 466 to 473 and the mean grain size was 70 nm. Comparison was m a d e with coarse grained samples. CORROSION RESISTANCE OF TITANIUM FILTERS I. Kangmei, L. Jichang (North-West Inst for Non-Ferrous Metal Research, China). The corrosion r e s i s t a n c e of Ti filter media in v a r i o u s solutions was investigated as functions of bend strength, permeability and m a x i m u m pore size. It was found t h a t the corrosion resistance is sensitive to the bend s t r e n g t h and less so to the permeability and pore size. Very good corrosion resistance to 0.09% sulphuric a c i d , 3% n i t r i c a c i d a n d 2% N a thiosulphate and good resistance to 2% hydrochloric acid were reported. NITROGEN ABSORPTION AND MAGNETIC P R O P E R T I E S OF RAPIDLY SOLIDIFIED ( R S ) SAMARIUM-IRONNITROGEN ALLOY POWDERS W. Li et al ( S w e d i s h I n s t for Metals Research, Stockholm, Sweden). An investigation of the adsorption of N by RS Sm-Fe powders was described. The o p t i m u m nitriding t e m p e r a t u r e was found to be 550°C. The nitrided powders were characterized and the presence of Sm2FelT-Nx was detected. The interstitial N atoms caused e x p a n s i o n of the lattice and
54 MPR December 1992
LITERATURE
REVIEW
an effective i n c r e a s e in t h e ordering temperature.
magnetic
A S S E S S M E N T OF INJECTION MOULDED ( I M ) 410 STAINLESS S T E E L P.F. Morley, C.M. Kipphut (General Electric Co, Schenectady, USA). The study which was described i n v e s t i g a t e d t h e p r o p e r t i e s of IM 410 stainless steel p a r t s with regard to design criteria for turbine use. Mechanical s t r e n g t h and fatigue S-N curves were d e t e r m i n e d and were discussed relative to microstructure and c o m p a r e d with similar wrought materials. SINTERING OF HIGH S P E E D S T E E L S ( H S S ) CONTAINING NIOBIUM F.A. Filho et al (Inst Pesq. Energiticas e Nucleares, Brazil). The use of VC in HSS was discussed. An i n v e s t i g a t i o n i n t o t h e effects of NbC, instead of VC, and process conditions, on the density and microstructure of M2 HSS was described. The Nb and C c o n t e n t s were varied. It was r e p o r t e d t h a t the sinterability was increased by increase in %C which also i n c r e a s e d t h e g r a i n size significantly. Addition of NbC reduced sinterability, the carbides being uniformly distributed. M e c h a n i c a l a l l o y i n g r e s u l t e d in good homogeneity of carbide distribution and lower porosity in the sintered HSS. PREPARATION OF PARTICLE DISPERSION STRENGTHENED (PDS) ALUMINIUM BY MECHANICAL ALLOYING
used to show t h a t NbA13 and NbC formed after 8 hours MA_ Ultrafine structures were obtained with Vickers h a r d n e s s e s of about 1000, the structures of the consolidated powders were discussed. STUDY OF THE USE OF POROUS TITANIUM IN THE FABRICATION OF SYNTHETIC HIPBONE MATERIALS W. Bende, G. Fuhe (Northwest Inst of NonFerrous Metal Research, China). The use of TiC4 powder coating on a synthetic composite hipbone material was d e s c r i b e d . The i m p o r t a n c e of p o w d e r properties and sintering were discussed. The mechanical properties of the material were determined. CHARACTERIZATION OF TITANIUM ALUMINIDE POWDER MADE BY PLASMA ROTATION ELECTRODE PROCESS ( P R E P ) L. Tao et al (Northwest Inst of Non-Ferrus Metal Research, China). PREP was used for p r o d u c t i o n of Ti3A1 powder with additions of Er a n d the p a p e r r e p o r t e d results of characterization of the powder by X-ray diffraction, optical and electron microscopy. The structures were found to d e p e n d on particle size. Coarse p o w d e r s , a b o v e 175 p m c o n t a i n e d dendritic [~ p h a s e and TiaA1 (~2). The fine p o w d e r c o n s i s t e d of d e n d r i t i c [3 solid solution. INFLUENCE OF CARBIDE POWDER COMPOSITION ON P R O P E R T I E S OF AIR SPRAYED PLASMA COATINGS
T. Takahashi, M. Motoyama (Prefectural Inst of Industrial Research, Hyogo, J a p a n ) . The p r o d u c t i o n o f BC d i s p e r s i o n s t r e n g t h e n e d A1 by mechanical alloying (MA) of A1, B and graphite powders was described. The milled powders were h e a t t r e a t e d at 300 to 650°C for various times and at 400°C for 1 hour. Fine particles of A1 borocarbide were p r e c i p i t a t e d which coarsened with increase in temperature. The h a r d n e s s was r e p o r t e d to increase with the a m o u n t of carbide and increase in t e m p e r a t u r e . The mechanical p r o p e r t i e s improved with increase in MA time.
L-M. Berger et al (Fraunhofer Institute, Germany). The i n t e r a c t i o n s of air with p l a s m a sprayed carbide powder coating were discussed with regard to decarburization a n d oxidation. An investigation of t h e effects of particle size on interactions with air was described in respect of mixed W and Ti c a r b i d e s . C loss a n d O gain were d e t e r m i n e d and correlated with coating porosity and wear behax~iour. A m e t h o d for p r o t e c t i o n of t h e c a r b i d e s d u r i n g spraying was presented.
PREPARATION OF NIOBIUM ALUMINIDE AND NIOBIUM ALUMINIDE-NIOBIUM CARBIDE COMPOSITES
DEVELOPMENT OF A U G E R SPECTROSCOPYTECHNIQUESFOR POWDER P R O D U C E D A N D P R O C E S S E D IN CONTROLLED A T M O S P H E R E S
T. Takahashi et al (Prefectural Inst of Industrial Research, Hyogo, J a p a n ) . The use of mechanical alloying (MA) for the p r e p a r a t i o n of A1, Nb and graphite powders was described. X-ray diffration was
A.V. Molotkov (NPO VILS, Russia) The use of A u g e r s p e c t r o s c o p y for surface analysis of powders was discussed with respect to post-processing c o n t a m i n a t i o n of s a m p l e s by air. Method
NOVEL MANUFACTURE OF RAPIDLY SOLIDIFIED ( R S ) PARTICLES BY MODIFIED MELT EXTRACTION G. S t e p h a n i (Frauhofer-Inst) ffir Angew a n d t e Materials-Forschung, Germany). A m e t h o d for p r o d u c t i o n of s h o r t metallic fibres, based on solidification on a notched edge of a rotating disc and a novel m e l t e x t r a c t i o n t e c h n i q u e w a s reported to enable cooling rates of I0n°C/ sec to be attained. The formation of metal matrix c o m p o s i t e s of SiC in a rapidly quenched matrix was reported.
PM properties MECHANICAL PROPERTIES OF NANOCRYSTALS PRODUCED FROM ULTRAFINE NICKEL POWDERS L.I. Trusov et al (Ultram International Inc,
USA). The mechanical properties of specimens formed from nanocrystalline Ni powder, 65 nm in size, were investigated. Powders were produced by inert gas evaporation/ condensation techniques and consolidated by isostatic pressure at 500°C and 4.4 GPa. At a density of 94 to 96% the vickers h a r d n e s s was 466 to 473 and the mean grain size was 70 nm. Comparison was m a d e with coarse grained samples. CORROSION RESISTANCE OF TITANIUM FILTERS I. Kangmei, L. Jichang (North-West Inst for Non-Ferrous Metal Research, China). The corrosion r e s i s t a n c e of Ti filter media in v a r i o u s solutions was investigated as functions of bend strength, permeability and m a x i m u m pore size. It was found t h a t the corrosion resistance is sensitive to the bend s t r e n g t h and less so to the permeability and pore size. Very good corrosion resistance to 0.09% sulphuric a c i d , 3% n i t r i c a c i d a n d 2% N a thiosulphate and good resistance to 2% hydrochloric acid were reported. NITROGEN ABSORPTION AND MAGNETIC P R O P E R T I E S OF RAPIDLY SOLIDIFIED ( R S ) SAMARIUM-IRONNITROGEN ALLOY POWDERS W. Li et al ( S w e d i s h I n s t for Metals Research, Stockholm, Sweden). An investigation of the adsorption of N by RS Sm-Fe powders was described. The o p t i m u m nitriding t e m p e r a t u r e was found to be 550°C. The nitrided powders were characterized and the presence of Sm2FelT-Nx was detected. The interstitial N atoms caused e x p a n s i o n of the lattice and
54 MPR December 1992
LITERATURE
REVIEW
an effective i n c r e a s e in t h e ordering temperature.
magnetic
A S S E S S M E N T OF INJECTION MOULDED ( I M ) 410 STAINLESS S T E E L P.F. Morley, C.M. Kipphut (General Electric Co, Schenectady, USA). The study which was described i n v e s t i g a t e d t h e p r o p e r t i e s of IM 410 stainless steel p a r t s with regard to design criteria for turbine use. Mechanical s t r e n g t h and fatigue S-N curves were d e t e r m i n e d and were discussed relative to microstructure and c o m p a r e d with similar wrought materials. SINTERING OF HIGH S P E E D S T E E L S ( H S S ) CONTAINING NIOBIUM F.A. Filho et al (Inst Pesq. Energiticas e Nucleares, Brazil). The use of VC in HSS was discussed. An i n v e s t i g a t i o n i n t o t h e effects of NbC, instead of VC, and process conditions, on the density and microstructure of M2 HSS was described. The Nb and C c o n t e n t s were varied. It was r e p o r t e d t h a t the sinterability was increased by increase in %C which also i n c r e a s e d t h e g r a i n size significantly. Addition of NbC reduced sinterability, the carbides being uniformly distributed. M e c h a n i c a l a l l o y i n g r e s u l t e d in good homogeneity of carbide distribution and lower porosity in the sintered HSS. PREPARATION OF PARTICLE DISPERSION STRENGTHENED (PDS) ALUMINIUM BY MECHANICAL ALLOYING
used to show t h a t NbA13 and NbC formed after 8 hours MA_ Ultrafine structures were obtained with Vickers h a r d n e s s e s of about 1000, the structures of the consolidated powders were discussed. STUDY OF THE USE OF POROUS TITANIUM IN THE FABRICATION OF SYNTHETIC HIPBONE MATERIALS W. Bende, G. Fuhe (Northwest Inst of NonFerrous Metal Research, China). The use of TiC4 powder coating on a synthetic composite hipbone material was d e s c r i b e d . The i m p o r t a n c e of p o w d e r properties and sintering were discussed. The mechanical properties of the material were determined. CHARACTERIZATION OF TITANIUM ALUMINIDE POWDER MADE BY PLASMA ROTATION ELECTRODE PROCESS ( P R E P ) L. Tao et al (Northwest Inst of Non-Ferrus Metal Research, China). PREP was used for p r o d u c t i o n of Ti3A1 powder with additions of Er a n d the p a p e r r e p o r t e d results of characterization of the powder by X-ray diffraction, optical and electron microscopy. The structures were found to d e p e n d on particle size. Coarse p o w d e r s , a b o v e 175 p m c o n t a i n e d dendritic [~ p h a s e and TiaA1 (~2). The fine p o w d e r c o n s i s t e d of d e n d r i t i c [3 solid solution. INFLUENCE OF CARBIDE POWDER COMPOSITION ON P R O P E R T I E S OF AIR SPRAYED PLASMA COATINGS
T. Takahashi, M. Motoyama (Prefectural Inst of Industrial Research, Hyogo, J a p a n ) . The p r o d u c t i o n o f BC d i s p e r s i o n s t r e n g t h e n e d A1 by mechanical alloying (MA) of A1, B and graphite powders was described. The milled powders were h e a t t r e a t e d at 300 to 650°C for various times and at 400°C for 1 hour. Fine particles of A1 borocarbide were p r e c i p i t a t e d which coarsened with increase in temperature. The h a r d n e s s was r e p o r t e d to increase with the a m o u n t of carbide and increase in t e m p e r a t u r e . The mechanical p r o p e r t i e s improved with increase in MA time.
L-M. Berger et al (Fraunhofer Institute, Germany). The i n t e r a c t i o n s of air with p l a s m a sprayed carbide powder coating were discussed with regard to decarburization a n d oxidation. An investigation of t h e effects of particle size on interactions with air was described in respect of mixed W and Ti c a r b i d e s . C loss a n d O gain were d e t e r m i n e d and correlated with coating porosity and wear behax~iour. A m e t h o d for p r o t e c t i o n of t h e c a r b i d e s d u r i n g spraying was presented.
PREPARATION OF NIOBIUM ALUMINIDE AND NIOBIUM ALUMINIDE-NIOBIUM CARBIDE COMPOSITES
DEVELOPMENT OF A U G E R SPECTROSCOPYTECHNIQUESFOR POWDER P R O D U C E D A N D P R O C E S S E D IN CONTROLLED A T M O S P H E R E S
T. Takahashi et al (Prefectural Inst of Industrial Research, Hyogo, J a p a n ) . The use of mechanical alloying (MA) for the p r e p a r a t i o n of A1, Nb and graphite powders was described. X-ray diffration was
A.V. Molotkov (NPO VILS, Russia) The use of A u g e r s p e c t r o s c o p y for surface analysis of powders was discussed with respect to post-processing c o n t a m i n a t i o n of s a m p l e s by air. Method