Fe-Cu-C sisteminde elementel tozlardan atritör öğütmesi ile geliştirilen çeşitli alaşımların mikroyapısal ve fiziksel özellikleri
Başlık çevirisi mevcut değil.
- Tez No: 46611
- Danışmanlar: PROF.DR. H. ERMAN TULGAR
- Tez Türü: Yüksek Lisans
- Konular: Metalurji Mühendisliği, Metallurgical Engineering
- Anahtar Kelimeler: Alaşımlar, Malzemeler, Mikroyapı, Alloys, Materials, Microstructure
- Yıl: 1995
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: Belirtilmemiş.
Özet
dimensional change values were close to zero for differing compositions and grinding times. XII
Özet (Çeviri)
removal parameters are very important in determining process cycle to produce compacts with the least swelling possible. In this study, the metallographical structure change and process parameters were investigated in the mechanical alloying process of Fe-Cu- C alloy produced by attritor milling. In order to determine optimum process parameters, preliminary experimental studies were conducted. The primary purposes of this investigation were : i) utilization of an original, not-tried and unorthodox technique, i. e. mechanical alloying (MA) for the development and production of various Fe-Cu-C alloys by varying the Cu content and the MA processing times, ii) achievement of optimum dimensional changes with respect to different commercial amounts of Cu ( 2 wt%, 5 wt%, 10 wt% Cu in the Fe-Cu-C alloy) and MA times in the Fe-Cu-C system and iii) optimization of the mechanical properties of these alloys in the Fe-Cu-C systems by means of mechnical alloying. Elemental powders of iron, copper, and graphite were used as starting materials. Mechanical alloying of Fe-Cu-C alloys which is prepared in various Cu content were performed in an attritor mill at a ball/powder ratio of 7:1 and a speed of 600 rev/min. At the end of 1, 5, 10, and 20 hour milling times, a small amount of sample was removed for X-ray diffactometry using CuKa radiation and SEM analysis. The mechanical Fe- Cu-C alloys were pressed into rectangular prism form using uniaxial press. Consolidated powder was sintered in the atmosphere (100 %H2) controlled sintering furnace at 1150°C. Specimens were measured before and after sintering. After the sintering, density measurements of compacted samples were done according to Archimed's principle. The microstructure of sintered compacts were observed by optical and scanning electron microscopes equipped with an energy dispersive microanalysis system (EDS). For microstructural analyses, samples were ground and polished metallographically and chemically etched with %2 Nital solution for 30 seconds. In order to determine the hardness properties, Rockwell hardness (B-l/16 in. ball) testing was carried out. Mechanical properties were determined by carrying out tensile tests using standard tensile specimens. The physical and mechanical properties of the alloys indicated the fact that increased Cu content in the Fe-Cu-C alloys and increased MA times enhance the mechanical properties and refines the microstructure with increasing tendency of free Cu deficiency in the structure. Furthermore, pearlite phase formations occur in the grain boundaries of the C dispersed Fe grains in the microstructure. The MA microstructures showed a certain resemblence to those Fe-Cu-C which were not mechanically alloyed. However, primary difference between the MA and non-MA Fe-Cu-C is that the Cu solid solubility in the former one is limited to thermodynamic values whereas for the MA Fe-Cu-C alloy solid solubility extension of Cu into Fe matrix by means of substitutional diffusion takes place. Additionally, XIdimensional change values were close to zero for differing compositions and grinding times. XIIremoval parameters are very important in determining process cycle to produce compacts with the least swelling possible. In this study, the metallographical structure change and process parameters were investigated in the mechanical alloying process of Fe-Cu- C alloy produced by attritor milling. In order to determine optimum process parameters, preliminary experimental studies were conducted. The primary purposes of this investigation were : i) utilization of an original, not-tried and unorthodox technique, i. e. mechanical alloying (MA) for the development and production of various Fe-Cu-C alloys by varying the Cu content and the MA processing times, ii) achievement of optimum dimensional changes with respect to different commercial amounts of Cu ( 2 wt%, 5 wt%, 10 wt% Cu in the Fe-Cu-C alloy) and MA times in the Fe-Cu-C system and iii) optimization of the mechanical properties of these alloys in the Fe-Cu-C systems by means of mechnical alloying. Elemental powders of iron, copper, and graphite were used as starting materials. Mechanical alloying of Fe-Cu-C alloys which is prepared in various Cu content were performed in an attritor mill at a ball/powder ratio of 7:1 and a speed of 600 rev/min. At the end of 1, 5, 10, and 20 hour milling times, a small amount of sample was removed for X-ray diffactometry using CuKa radiation and SEM analysis. The mechanical Fe- Cu-C alloys were pressed into rectangular prism form using uniaxial press. Consolidated powder was sintered in the atmosphere (100 %H2) controlled sintering furnace at 1150°C. Specimens were measured before and after sintering. After the sintering, density measurements of compacted samples were done according to Archimed's principle. The microstructure of sintered compacts were observed by optical and scanning electron microscopes equipped with an energy dispersive microanalysis system (EDS). For microstructural analyses, samples were ground and polished metallographically and chemically etched with %2 Nital solution for 30 seconds. In order to determine the hardness properties, Rockwell hardness (B-l/16 in. ball) testing was carried out. Mechanical properties were determined by carrying out tensile tests using standard tensile specimens. The physical and mechanical properties of the alloys indicated the fact that increased Cu content in the Fe-Cu-C alloys and increased MA times enhance the mechanical properties and refines the microstructure with increasing tendency of free Cu deficiency in the structure. Furthermore, pearlite phase formations occur in the grain boundaries of the C dispersed Fe grains in the microstructure. The MA microstructures showed a certain resemblence to those Fe-Cu-C which were not mechanically alloyed. However, primary difference between the MA and non-MA Fe-Cu-C is that the Cu solid solubility in the former one is limited to thermodynamic values whereas for the MA Fe-Cu-C alloy solid solubility extension of Cu into Fe matrix by means of substitutional diffusion takes place. Additionally, XIdimensional change values were close to zero for differing compositions and grinding times. XIIremoval parameters are very important in determining process cycle to produce compacts with the least swelling possible. In this study, the metallographical structure change and process parameters were investigated in the mechanical alloying process of Fe-Cu- C alloy produced by attritor milling. In order to determine optimum process parameters, preliminary experimental studies were conducted. The primary purposes of this investigation were : i) utilization of an original, not-tried and unorthodox technique, i. e. mechanical alloying (MA) for the development and production of various Fe-Cu-C alloys by varying the Cu content and the MA processing times, ii) achievement of optimum dimensional changes with respect to different commercial amounts of Cu ( 2 wt%, 5 wt%, 10 wt% Cu in the Fe-Cu-C alloy) and MA times in the Fe-Cu-C system and iii) optimization of the mechanical properties of these alloys in the Fe-Cu-C systems by means of mechnical alloying. Elemental powders of iron, copper, and graphite were used as starting materials. Mechanical alloying of Fe-Cu-C alloys which is prepared in various Cu content were performed in an attritor mill at a ball/powder ratio of 7:1 and a speed of 600 rev/min. At the end of 1, 5, 10, and 20 hour milling times, a small amount of sample was removed for X-ray diffactometry using CuKa radiation and SEM analysis. The mechanical Fe- Cu-C alloys were pressed into rectangular prism form using uniaxial press. Consolidated powder was sintered in the atmosphere (100 %H2) controlled sintering furnace at 1150°C. Specimens were measured before and after sintering. After the sintering, density measurements of compacted samples were done according to Archimed's principle. The microstructure of sintered compacts were observed by optical and scanning electron microscopes equipped with an energy dispersive microanalysis system (EDS). For microstructural analyses, samples were ground and polished metallographically and chemically etched with %2 Nital solution for 30 seconds. In order to determine the hardness properties, Rockwell hardness (B-l/16 in. ball) testing was carried out. Mechanical properties were determined by carrying out tensile tests using standard tensile specimens. The physical and mechanical properties of the alloys indicated the fact that increased Cu content in the Fe-Cu-C alloys and increased MA times enhance the mechanical properties and refines the microstructure with increasing tendency of free Cu deficiency in the structure. Furthermore, pearlite phase formations occur in the grain boundaries of the C dispersed Fe grains in the microstructure. The MA microstructures showed a certain resemblence to those Fe-Cu-C which were not mechanically alloyed. However, primary difference between the MA and non-MA Fe-Cu-C is that the Cu solid solubility in the former one is limited to thermodynamic values whereas for the MA Fe-Cu-C alloy solid solubility extension of Cu into Fe matrix by means of substitutional diffusion takes place. Additionally, XIdimensional change values were close to zero for differing compositions and grinding times. XII
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