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Production of Ni-Base alloy with high corrosion and wear resistance by reaction sintering process
IRON BASE OXIDE D I S P E R S I O N S T R E N G T H E N E D ( O D S ) ALLOYS WITH IMPROVED MECHANICAL STRENGTH S. Kazimierzak et al, (Dour Metal SA, Belgium), Powder Metallurgy International, Vol 23, No 1, 1991, 41-44. A new range of Fe-based ODS alloys has been developed for use at t e m p e r a t u r e s up to 1200°C. Homogeneous powders of alloys based on Fe-l.5% Mo-0.6% Ti- 0.5% Y203 with Cr (13 to 20%) and A1 (3 to 6%) were p r e p a r e d by m e c h a n i c a l alloying. The powders were compacted at high temperatures and then deformed. Mechanical properties and oxidation resistancewere measured. The alloy with 16.5% Cr and 4.5% A1 was found to provide the best combination of strength, deformability and oxidation resistance with good creep, resistance at 1100 to 1200°C.
STRUCTURE AND PROPERTIES OF SINTERED STEEL ALLOYS H. Frydrych, A. Nowakowski, (Academy of Mining and Metallurgy, Poland), Metall, Odlew., Vol 15, No 3, 1989, 401-414. In Polish. The microstructure and properties of sintered steel made from prealloyed powders containing additions of Ni, Cu, Mo and Mn were investigated. The sintered materials were forged and heat treated, and increases in density and h a r d n e s s were observed. MICROSTRUCTURE AND H A R D N E S S VARIATIONS DURING COMPACTION OF AMORPHOUS ( F e - N i ) - (Si-P-B) POWDERS V.P. Manov et al, Isvestia Akad Nauk SSSR Metall, No 2, 1990, 117-119. In Russian. M i x t u r e s of Fe-Ni a n d Si-P-B alloy p o w d e r s w e r e c o n s o l i d a t e d by w a r m pressing at less t h a n the recrystallization t e m p e r a t u r e . It w a s f o u n d t h a t t h e structure and microhardness of the compacts depends on the pressing t e m p e r a t u r e a t 400, 450 a n d 500°C. Property results are discussed in relation to the structure.
A corrosion and wear resistant alloy, Ni17.5 wt% Cr-24% Mo-3.6% B-2.9% Si-l% Cu, has been p r o d u c e d from mixtures of Ni, Mo, Si, Cu a n d CrB p o w d e r s by r e a c t i o n s i n t e r i n g a n d HIP. During HIPing t h e boride M3B2 was formed from the CrB. The PM alloy showed corrosion and wear resistance b e t t e r t h a n cast materials and comparable with t h o s e of HastelloyC. The high corrosion resistance was attributed to the presence of Cu which retarded the preferential corrosion of the matrix. The high wear resistance was considered to be due to the fine dispersion of the boride particles. The alloy was bonded to the inner surface of a steel cylinder which was used as a c o m p o n e n t in a p l a s t i c m o u l d i n g machine.
SHAPE AND STRUCTURE OF RAPIDLY SOLIDIFIED Ni-BASED POWDERS A~A. Ivlev et al, Poroskovaya Metallurgiya, No 8, 1990, 1-6. In Russian. The effect of c o o l i n g r a t e on t h e structure and p h a s e composition of Ni-16 to 18 wt% Cr-3.8 to 4.5% Si-3 to 4% B-0.8 to 1.2% C-5% Fe has been investigated. It was shown t h a t a m o r p h o u s p o w d e r can be produced by the use of a high energy gas to impinge the metal droplets onto the crystallizer surface. Metallography and Xray diffraction have been used to study c h a n g e in t h e p h a s e c o m p o s i t i o n a a function of particle shape. The a m o r p h o u s powdershave a flaky morphology. CHANGES IN THE STRUCTURE OF WEAR R E S I S T A N T Ni BASE ALLOYS U N D E R THERMAL TREATMENT V.V. Rodionov et al, Poroskovaya Metallurgiya, No 8, 1990, 46-49. In Russian. The p h a s e c o m p o s i t i o n of a n n e a l e d (800°C for 4 hours) and non-annealed NiCr-Si-B alloys p o w d e r s , a n d c o a t i n g s prepared from them, have been investigated by X-ray p h a s e analysis. The properties were found to d e p e n d on the concentration of borides and silicides in the alloys, increase of which results in higher h a r d n e s s and porosity. Annealing results in decomposition of the Ni rich solid solution (7 p h a s e ) .
Nickel
SEGREGATION OF C AND B IN ATOMIZED Ni BASE ALLOY
PRODUCTION OF Ni-BASE ALLOY WITH HIGH CORROSION AND WEAR RESISTANCE BY REACTION SINTERING PROCESS
A.V. Shulga et al, Isvestia Akad Nauk SSSR MetaU, No 2, 1990, 51-53. In Russian. The effect of B additions (0.01 to 0.15%) on C and B segregation and mechanical properties of a PM Ni base alloy were investigated by microscopy, autoradiography and X-ray diffraction. It was found t h a t increase of B c o n t e n t
M. Morishita et al, J Japan Soc Powder and Powder Metallurgy, Vol 37, No 8, 1990, 1143-1147. In Japanese.
52 MPR April 1991
resulted in an increase in B segregation at grain boundaries and a reduction in C segregation.
Titanium CONTACT FORMATION DURING ELECTRO-PULSE SINTERING ( E P S ) OFTi ALLOY POWDERS P.A. Vityaz et al, Poroskovaya Metallurgiya, No 7, 1990, 20-23. In Russian. T h e c h a r a c t e r i s t i c s o f p o r o u s Ti produced by electro-pulse sintering (EPS) of p o w d e r s have b e e n e x a m i n e d a n d compared with t h o s e of vacuum sintered materials. It is shown t h a t u n d e r EPS the microstructure and chemical composition of t h e original p o w d e r is u n c h a n g e d . P a r t i c l e s h a p e is r e t a i n e d a n d t h e p a r t i c l e s are b o n d e d by fusion at the areas of contact between particles by Joule heat release.
Tungsten E F F E C T OF HEAT TREATMENT DURATION ON THE P R O P E R T I E S OF WNi-Fe HEAVY ALLOYS T. Kaneko, J Japan Soc Powder and Powder Metallurgy, Vol 37, No 8, 1990, 1148-1156. In Japanese. The p a p e r describes efforts to improve the mechanical properties of cold swaged W-Ni-Fe heavy alloys by v a c u u m h e a t t r e a t m e n t in the range 400-1200°C for 124 hours. Heat t r e a t m e n t at 600°C for 5 hours resulted in an increase in yield and tensile strength but with a reduction in elongation. A t e m p e r a t u r e of 1200°C for 5 hours resulted in a reduction in strength, h a r d n e s s and elongation. SEM of fracture surfaces s u g g e s t s t h a t t h e i n c r e a s e in mechanical properties is due to increases in the s t r e n g t h s of the W / m a t r i x interface and W/W grain boundaries.
CORRELATION OF STRUCTURE FORMATION DURING SINTERING AND MECHANICAL P R O P E R T I E S OF SINTERED TUNGSTEN P.Y. Radchenko et al, Poroskovaya Metallurgiya, No 8, 1990, 36-41. In Russian. The structure and properties of sintered W in the porosity range 5 to 40% have been s t u d i e d . As p o r o s i t y is r e d u c e d it is r e p o r t e d t h a t the bending s t r e n g t h increases in a linear fashion and this is attributed to improvements in grain boundary structure and porosity patterns, the transition from open to closed pores and the formation of small spherical pores at
STRUCTURE AND PROPERTIES OF SINTERED STEEL ALLOYS H. Frydrych, A. Nowakowski, (Academy of Mining and Metallurgy, Poland), Metall, Odlew., Vol 15, No 3, 1989, 401-414. In Polish. The microstructure and properties of sintered steel made from prealloyed powders containing additions of Ni, Cu, Mo and Mn were investigated. The sintered materials were forged and heat treated, and increases in density and h a r d n e s s were observed. MICROSTRUCTURE AND H A R D N E S S VARIATIONS DURING COMPACTION OF AMORPHOUS ( F e - N i ) - (Si-P-B) POWDERS V.P. Manov et al, Isvestia Akad Nauk SSSR Metall, No 2, 1990, 117-119. In Russian. M i x t u r e s of Fe-Ni a n d Si-P-B alloy p o w d e r s w e r e c o n s o l i d a t e d by w a r m pressing at less t h a n the recrystallization t e m p e r a t u r e . It w a s f o u n d t h a t t h e structure and microhardness of the compacts depends on the pressing t e m p e r a t u r e a t 400, 450 a n d 500°C. Property results are discussed in relation to the structure.
A corrosion and wear resistant alloy, Ni17.5 wt% Cr-24% Mo-3.6% B-2.9% Si-l% Cu, has been p r o d u c e d from mixtures of Ni, Mo, Si, Cu a n d CrB p o w d e r s by r e a c t i o n s i n t e r i n g a n d HIP. During HIPing t h e boride M3B2 was formed from the CrB. The PM alloy showed corrosion and wear resistance b e t t e r t h a n cast materials and comparable with t h o s e of HastelloyC. The high corrosion resistance was attributed to the presence of Cu which retarded the preferential corrosion of the matrix. The high wear resistance was considered to be due to the fine dispersion of the boride particles. The alloy was bonded to the inner surface of a steel cylinder which was used as a c o m p o n e n t in a p l a s t i c m o u l d i n g machine.
SHAPE AND STRUCTURE OF RAPIDLY SOLIDIFIED Ni-BASED POWDERS A~A. Ivlev et al, Poroskovaya Metallurgiya, No 8, 1990, 1-6. In Russian. The effect of c o o l i n g r a t e on t h e structure and p h a s e composition of Ni-16 to 18 wt% Cr-3.8 to 4.5% Si-3 to 4% B-0.8 to 1.2% C-5% Fe has been investigated. It was shown t h a t a m o r p h o u s p o w d e r can be produced by the use of a high energy gas to impinge the metal droplets onto the crystallizer surface. Metallography and Xray diffraction have been used to study c h a n g e in t h e p h a s e c o m p o s i t i o n a a function of particle shape. The a m o r p h o u s powdershave a flaky morphology. CHANGES IN THE STRUCTURE OF WEAR R E S I S T A N T Ni BASE ALLOYS U N D E R THERMAL TREATMENT V.V. Rodionov et al, Poroskovaya Metallurgiya, No 8, 1990, 46-49. In Russian. The p h a s e c o m p o s i t i o n of a n n e a l e d (800°C for 4 hours) and non-annealed NiCr-Si-B alloys p o w d e r s , a n d c o a t i n g s prepared from them, have been investigated by X-ray p h a s e analysis. The properties were found to d e p e n d on the concentration of borides and silicides in the alloys, increase of which results in higher h a r d n e s s and porosity. Annealing results in decomposition of the Ni rich solid solution (7 p h a s e ) .
Nickel
SEGREGATION OF C AND B IN ATOMIZED Ni BASE ALLOY
PRODUCTION OF Ni-BASE ALLOY WITH HIGH CORROSION AND WEAR RESISTANCE BY REACTION SINTERING PROCESS
A.V. Shulga et al, Isvestia Akad Nauk SSSR MetaU, No 2, 1990, 51-53. In Russian. The effect of B additions (0.01 to 0.15%) on C and B segregation and mechanical properties of a PM Ni base alloy were investigated by microscopy, autoradiography and X-ray diffraction. It was found t h a t increase of B c o n t e n t
M. Morishita et al, J Japan Soc Powder and Powder Metallurgy, Vol 37, No 8, 1990, 1143-1147. In Japanese.
52 MPR April 1991
resulted in an increase in B segregation at grain boundaries and a reduction in C segregation.
Titanium CONTACT FORMATION DURING ELECTRO-PULSE SINTERING ( E P S ) OFTi ALLOY POWDERS P.A. Vityaz et al, Poroskovaya Metallurgiya, No 7, 1990, 20-23. In Russian. T h e c h a r a c t e r i s t i c s o f p o r o u s Ti produced by electro-pulse sintering (EPS) of p o w d e r s have b e e n e x a m i n e d a n d compared with t h o s e of vacuum sintered materials. It is shown t h a t u n d e r EPS the microstructure and chemical composition of t h e original p o w d e r is u n c h a n g e d . P a r t i c l e s h a p e is r e t a i n e d a n d t h e p a r t i c l e s are b o n d e d by fusion at the areas of contact between particles by Joule heat release.
Tungsten E F F E C T OF HEAT TREATMENT DURATION ON THE P R O P E R T I E S OF WNi-Fe HEAVY ALLOYS T. Kaneko, J Japan Soc Powder and Powder Metallurgy, Vol 37, No 8, 1990, 1148-1156. In Japanese. The p a p e r describes efforts to improve the mechanical properties of cold swaged W-Ni-Fe heavy alloys by v a c u u m h e a t t r e a t m e n t in the range 400-1200°C for 124 hours. Heat t r e a t m e n t at 600°C for 5 hours resulted in an increase in yield and tensile strength but with a reduction in elongation. A t e m p e r a t u r e of 1200°C for 5 hours resulted in a reduction in strength, h a r d n e s s and elongation. SEM of fracture surfaces s u g g e s t s t h a t t h e i n c r e a s e in mechanical properties is due to increases in the s t r e n g t h s of the W / m a t r i x interface and W/W grain boundaries.
CORRELATION OF STRUCTURE FORMATION DURING SINTERING AND MECHANICAL P R O P E R T I E S OF SINTERED TUNGSTEN P.Y. Radchenko et al, Poroskovaya Metallurgiya, No 8, 1990, 36-41. In Russian. The structure and properties of sintered W in the porosity range 5 to 40% have been s t u d i e d . As p o r o s i t y is r e d u c e d it is r e p o r t e d t h a t the bending s t r e n g t h increases in a linear fashion and this is attributed to improvements in grain boundary structure and porosity patterns, the transition from open to closed pores and the formation of small spherical pores at