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Dynamic compaction of amorphous iron-nickel-boron powders
PM S I N T E R I N G OF M A N G A N E S E ALUMINIUM AND MANGANESEALUMINIUM-CARBON MAGNETS
J.H. Hunag and P.C. Kuo, Materials Science and Engineering B, Vol B14, No 1, 1992, 75-79. Conventional PM technology was used to make Mn-Al and Mn-AI-C magnet alloys. The magnetic properties are reported to d e p e n d on g r a i n s i z e s a n d p r o c e s s conditions, grain size being f n e r t h a n in cast m a g n e t s . A d d i t i o n of C leads to precipitation within the grains. The grain size was found to be d e p e n d e n t on powder particle size. The o p t i m u m sintering is at 1235C. Compacting in a magnetic field was i n e f f e c t i v e in p r o d u c i n g magnetic anisotropy. DYNAMIC C O M P A C T I O N OF A M O R P H O U S IRON-NICKEL-BORON POWDERS
T. Syono et al (Tohoku University, Sendal, J a p a n ) , d Materials Science Letters, Vol 11, No 15, 1992, 1072-1074. The details of a dynamic compaction process for the consolidation of a m o r p h o u s Fe-17% Ni-8% ]) powder, made from melt spun ribbons, are described. Densities up to 93% are r e p o r t e d and t h e a m o r p h o u s structure is retained.
H a r d m a t e r i a l s a n d tool steels C O M P U T E R S I M U L A T I O N OF T U N G S T E N C A R B I D E POWDER SIZE DISTRIBUTIONS
N..I. McCormick and B. Roebuck (National Physical Laboratory, Teddington, UK), PowderMetallurgy, Vol 36, No l, 1993, 31-41. Particle size distribution images, which can be d i s p l a y e d in m o n o c h r o m e for comparison with SEM images, or in size coded colour, to illustrate the distribution, h a v e b e e n g e n e r a t e d by a c o m p u t e r simulation. Images for i n s t r u m e n t a l or m i c r o s c o p i c p a r t i c l e size d i s t r i b u t i o n s were used to clarify t h e value of t h e various methods. WC powders were used in the study. Problems arising for powders less than 0.5 pm were identified. S I N T E R I N G OF WATER A T O M I Z E D HIGH S P E E D S T E E L P O W D E R S I N VACUUM A N D N I T R O G E N ATMOSPHERES
I. Urrutibeaskoa and J J . Urcola, (Escuela de Ingenieros Industiales, San Sebastian, Spain), Powder Metallurgy, Vol 36, No l, 1993, 47-54. The sintering of water atomized ASP30 HSS was investigated in vacuum or a H-HCH4 mixture. The gas a t m o s p h e r e gave a density of 99 to 100% at 30 to 45°C lower than vacuum sintering. 0.45 to 0.75 wt% N was absorbed from the gas. Fine carbides
44
MPR September 1993
LITERATURE
REVIEW
were formed after vacuum sintering and carbonitride particles after gas sintering p a r t i c l e sizes b e i n g a b o u t 1 pm a n d resistant to growth on prolonged sintering. The absence of eutectic films and grain is noted. S I N T E R A B I L I T Y OF H I G H S P E E D S T E E L S R E I N F O R C E D WITH TUNGSTEN AND TITANIUM CARBIDES.
J.M. Torralba et al (Polytechnic University of Madrid, Madrid, Spain), Powder Metallurgy, Vol 35, No 1, 1993, 55-56. The use of HSS as a l t e r n a t i v e s to c e m e n t e d c a r b i d e s in cutting tool and wear resistant al)plications is discussed with reference to the m e a n s of improving the properties of sintered materials. An investigation in which TiC a n d / o r WC were added, to M2 or T15 HSS, is described. It is reported t h a t the addition of l0 wt% of a WC-Co p o w d e r r e s u l t e d in i m p r o v e d sintering at lower t e m p e r a t u r e s and gave increased flexural strength. TiC had little effect and TiC a n d WC t o g e t h e r gave i n t e r m e d i a t e results. Vacuum s i n t e r i n g gave the best sintered material. D E V E L O P M E N T OF A S I N T E R E D T I T A N I U M BASE HARD ALLOY
K. Tokumoto et al (Nippon Tungsten Co Ltd, Fukuoka, J a p a n ) , J J a p a n Soc Powder and Powder Metallurgy, Vol 40, No l, 1993, 66-71. (In J a p a n e s e ) . An investigation of the structure and properties of sintered Ti-Mo-(33 to 80)wt% TiC alloys is described. The materials are shown to consist of two phases, TiC× and [~Ti. The lattice c o n s t a n t s of TiC× were found to increase with %TiC which also reduced those of [~Ti. The strength was increased and the transverse rupture strength is reduced by increase in TiC. It is also concluded t h a t Ti-Mo-25 wt% TiC has a better combination of h a r d n e s s and TRS t h a n Ti-Mo-33% TiC. TITANIUM BORIDE DISPERSION S T R E N G T H E N E D T U N G S T E N BASE HARD ALLOY
N. S h i n o h a r a et al (Toyo K o h a n Co, K u d a m a t u , J a p a n ) , J J a p a n Soc and Powder and Powder Metallurgy, Vol 40, No 1, 1993, 72-75. (In J a p a n e s e ) . It is reported t h a t a new hard alloy with the composition W-10 vol% Mo2NiB2_(0 to 13)% TiB,~ h a s b e e n p r o d u c e d by PM methods. Sintering was in Ar at a pressure of 0.98 MPa for 30 rains at 1700~C. The alloy is reported to have good sliding wear resistance and good resistance to attack by molten A1 alloys. It is suggested t h a t the alloy will find applications in p a r t s of die casting machines for A1 alloys. P R O P E R T I E S OF N E W C H R O M I U M H A R D - F A C I N G ALLOYS
K. Hidaka et al (Fukuda Metal Foil and
Powder Co Ltd, Kyoto, J a p a n ) , J J a p a n Soc Powder and Powder Metallurgy, Vol 40, No l, 1993, 76-79. (In J a p a n e s e ) . The d e v e l o p m e n t of Cr-Ni-X alloys, where X represents small a m o u n t s of Mo, B, and Si, and with at least 50 wt% Cr is described. Hardness, impact strength wear and corrosion resistance and weldability were assessed and compared with conventional Co and Ni base hard facing alloys. It is reported that the alloys were suitable as hard facing materials, wear and corrosion resistance was better t h a n the Co or Ni base alloys and the weldability was adequate for the VIA process.
C O M P A C T I O N OF C O M B U S T E D HARD MATERIAL P O W D E R S
K.L. Ephishin et al, Poroshkovaya Metallurgiya, No 6, lq92, 14-19. (In Russian). The p r o d u c t s of combustion of Zr-C, TaC, Ti-B-C and Ti-Cr-C-Ni powder mixtures were investigated. It is reported t h a t the compaction of the c o m b u s t e d materials occurs in stages depending on conditions of c o m b u s t i o n a n d c o n s o l i d a t i o n a n d mixture composition. The presence of a liquid p h a s e and refractory constituents is s h o w n to have a s i g n i f i c a n t effect of contraction. Compaction mechanisms identified are sliding, plastic deformation and pre filling. Optimum conditions for m a x i m u m density are established. E F F E C T S OF H E A T I N G R A T E S ON P R O P E R T I E S OF HARD ALLOYS
A.S. Drashinsky et al, Poroshkovaya Metallurgiya, No 6, 1992, 29-31. (In Russian). It is reported t h a t the rapid electric heating of certain hard alloy leads to a degradation in mechanical properties. This is a t t r i b u t e d to s w e l l i n g c a u s e d by volatilization of inclusions, K a n d Na compounds, and occurs in t h e t e m p e r a t u r e range 1400 to 1800'C. It is suggested t h a t the p h e n o m e n a described are caused by stress relaxation. S C A L I N G R E S I S T A N C E OF BINARY TITANIUM AND CHROMIUM CARBIDES
G.N. Kimratov et al, Poroshkovaya Metallurgiya, No 6, 1992, 31-35. (In Russian). Oxidation scaling of Ti and Cr carbides was investigated and found to iollow a parabolic rate law in the initial stages, rates subsequently declining. It is reported t h a t the alloy containing 35 tool% Cr carbide has the highest resistance to oxidation. F O R M A T I O N OF R I N G S T R U C T U R E S D U R I N G S I N T E R I N G OF T I T A N I U M CARBIDE-NICKEL-MOLYBDENUM
V.A. Potapenko et al, Poroshkovaya Metallurgiya, No 6, 1992, 75-79. (In Russian). An Auger spectroscopy study of interface c o m p o s i t i o n between TiC and a Ni-Mo matrix is reported. The distribution of Ti,
J.H. Hunag and P.C. Kuo, Materials Science and Engineering B, Vol B14, No 1, 1992, 75-79. Conventional PM technology was used to make Mn-Al and Mn-AI-C magnet alloys. The magnetic properties are reported to d e p e n d on g r a i n s i z e s a n d p r o c e s s conditions, grain size being f n e r t h a n in cast m a g n e t s . A d d i t i o n of C leads to precipitation within the grains. The grain size was found to be d e p e n d e n t on powder particle size. The o p t i m u m sintering is at 1235C. Compacting in a magnetic field was i n e f f e c t i v e in p r o d u c i n g magnetic anisotropy. DYNAMIC C O M P A C T I O N OF A M O R P H O U S IRON-NICKEL-BORON POWDERS
T. Syono et al (Tohoku University, Sendal, J a p a n ) , d Materials Science Letters, Vol 11, No 15, 1992, 1072-1074. The details of a dynamic compaction process for the consolidation of a m o r p h o u s Fe-17% Ni-8% ]) powder, made from melt spun ribbons, are described. Densities up to 93% are r e p o r t e d and t h e a m o r p h o u s structure is retained.
H a r d m a t e r i a l s a n d tool steels C O M P U T E R S I M U L A T I O N OF T U N G S T E N C A R B I D E POWDER SIZE DISTRIBUTIONS
N..I. McCormick and B. Roebuck (National Physical Laboratory, Teddington, UK), PowderMetallurgy, Vol 36, No l, 1993, 31-41. Particle size distribution images, which can be d i s p l a y e d in m o n o c h r o m e for comparison with SEM images, or in size coded colour, to illustrate the distribution, h a v e b e e n g e n e r a t e d by a c o m p u t e r simulation. Images for i n s t r u m e n t a l or m i c r o s c o p i c p a r t i c l e size d i s t r i b u t i o n s were used to clarify t h e value of t h e various methods. WC powders were used in the study. Problems arising for powders less than 0.5 pm were identified. S I N T E R I N G OF WATER A T O M I Z E D HIGH S P E E D S T E E L P O W D E R S I N VACUUM A N D N I T R O G E N ATMOSPHERES
I. Urrutibeaskoa and J J . Urcola, (Escuela de Ingenieros Industiales, San Sebastian, Spain), Powder Metallurgy, Vol 36, No l, 1993, 47-54. The sintering of water atomized ASP30 HSS was investigated in vacuum or a H-HCH4 mixture. The gas a t m o s p h e r e gave a density of 99 to 100% at 30 to 45°C lower than vacuum sintering. 0.45 to 0.75 wt% N was absorbed from the gas. Fine carbides
44
MPR September 1993
LITERATURE
REVIEW
were formed after vacuum sintering and carbonitride particles after gas sintering p a r t i c l e sizes b e i n g a b o u t 1 pm a n d resistant to growth on prolonged sintering. The absence of eutectic films and grain is noted. S I N T E R A B I L I T Y OF H I G H S P E E D S T E E L S R E I N F O R C E D WITH TUNGSTEN AND TITANIUM CARBIDES.
J.M. Torralba et al (Polytechnic University of Madrid, Madrid, Spain), Powder Metallurgy, Vol 35, No 1, 1993, 55-56. The use of HSS as a l t e r n a t i v e s to c e m e n t e d c a r b i d e s in cutting tool and wear resistant al)plications is discussed with reference to the m e a n s of improving the properties of sintered materials. An investigation in which TiC a n d / o r WC were added, to M2 or T15 HSS, is described. It is reported t h a t the addition of l0 wt% of a WC-Co p o w d e r r e s u l t e d in i m p r o v e d sintering at lower t e m p e r a t u r e s and gave increased flexural strength. TiC had little effect and TiC a n d WC t o g e t h e r gave i n t e r m e d i a t e results. Vacuum s i n t e r i n g gave the best sintered material. D E V E L O P M E N T OF A S I N T E R E D T I T A N I U M BASE HARD ALLOY
K. Tokumoto et al (Nippon Tungsten Co Ltd, Fukuoka, J a p a n ) , J J a p a n Soc Powder and Powder Metallurgy, Vol 40, No l, 1993, 66-71. (In J a p a n e s e ) . An investigation of the structure and properties of sintered Ti-Mo-(33 to 80)wt% TiC alloys is described. The materials are shown to consist of two phases, TiC× and [~Ti. The lattice c o n s t a n t s of TiC× were found to increase with %TiC which also reduced those of [~Ti. The strength was increased and the transverse rupture strength is reduced by increase in TiC. It is also concluded t h a t Ti-Mo-25 wt% TiC has a better combination of h a r d n e s s and TRS t h a n Ti-Mo-33% TiC. TITANIUM BORIDE DISPERSION S T R E N G T H E N E D T U N G S T E N BASE HARD ALLOY
N. S h i n o h a r a et al (Toyo K o h a n Co, K u d a m a t u , J a p a n ) , J J a p a n Soc and Powder and Powder Metallurgy, Vol 40, No 1, 1993, 72-75. (In J a p a n e s e ) . It is reported t h a t a new hard alloy with the composition W-10 vol% Mo2NiB2_(0 to 13)% TiB,~ h a s b e e n p r o d u c e d by PM methods. Sintering was in Ar at a pressure of 0.98 MPa for 30 rains at 1700~C. The alloy is reported to have good sliding wear resistance and good resistance to attack by molten A1 alloys. It is suggested t h a t the alloy will find applications in p a r t s of die casting machines for A1 alloys. P R O P E R T I E S OF N E W C H R O M I U M H A R D - F A C I N G ALLOYS
K. Hidaka et al (Fukuda Metal Foil and
Powder Co Ltd, Kyoto, J a p a n ) , J J a p a n Soc Powder and Powder Metallurgy, Vol 40, No l, 1993, 76-79. (In J a p a n e s e ) . The d e v e l o p m e n t of Cr-Ni-X alloys, where X represents small a m o u n t s of Mo, B, and Si, and with at least 50 wt% Cr is described. Hardness, impact strength wear and corrosion resistance and weldability were assessed and compared with conventional Co and Ni base hard facing alloys. It is reported that the alloys were suitable as hard facing materials, wear and corrosion resistance was better t h a n the Co or Ni base alloys and the weldability was adequate for the VIA process.
C O M P A C T I O N OF C O M B U S T E D HARD MATERIAL P O W D E R S
K.L. Ephishin et al, Poroshkovaya Metallurgiya, No 6, lq92, 14-19. (In Russian). The p r o d u c t s of combustion of Zr-C, TaC, Ti-B-C and Ti-Cr-C-Ni powder mixtures were investigated. It is reported t h a t the compaction of the c o m b u s t e d materials occurs in stages depending on conditions of c o m b u s t i o n a n d c o n s o l i d a t i o n a n d mixture composition. The presence of a liquid p h a s e and refractory constituents is s h o w n to have a s i g n i f i c a n t effect of contraction. Compaction mechanisms identified are sliding, plastic deformation and pre filling. Optimum conditions for m a x i m u m density are established. E F F E C T S OF H E A T I N G R A T E S ON P R O P E R T I E S OF HARD ALLOYS
A.S. Drashinsky et al, Poroshkovaya Metallurgiya, No 6, 1992, 29-31. (In Russian). It is reported t h a t the rapid electric heating of certain hard alloy leads to a degradation in mechanical properties. This is a t t r i b u t e d to s w e l l i n g c a u s e d by volatilization of inclusions, K a n d Na compounds, and occurs in t h e t e m p e r a t u r e range 1400 to 1800'C. It is suggested t h a t the p h e n o m e n a described are caused by stress relaxation. S C A L I N G R E S I S T A N C E OF BINARY TITANIUM AND CHROMIUM CARBIDES
G.N. Kimratov et al, Poroshkovaya Metallurgiya, No 6, 1992, 31-35. (In Russian). Oxidation scaling of Ti and Cr carbides was investigated and found to iollow a parabolic rate law in the initial stages, rates subsequently declining. It is reported t h a t the alloy containing 35 tool% Cr carbide has the highest resistance to oxidation. F O R M A T I O N OF R I N G S T R U C T U R E S D U R I N G S I N T E R I N G OF T I T A N I U M CARBIDE-NICKEL-MOLYBDENUM
V.A. Potapenko et al, Poroshkovaya Metallurgiya, No 6, 1992, 75-79. (In Russian). An Auger spectroscopy study of interface c o m p o s i t i o n between TiC and a Ni-Mo matrix is reported. The distribution of Ti,