Awfa Abdullah - Academia.edu (original) (raw)
Papers by Awfa Abdullah
Journal of Al-Nahrain University Science, 2010
Modeling of diffusion bonding of Inconel 600 /Pyrolytic Graphite and Inconel 600/steel interlayer... more Modeling of diffusion bonding of Inconel 600 /Pyrolytic Graphite and Inconel 600/steel interlayer/Pyrolytic Graphite is investigated in this research. Modeling implies utilization of ANSYS package to predict axisymmetric thermoelastic finite element analysis from the above materials. The model is used; to calculate thermal stresses induced across diffusion bonded joints. Investigating thermal stress levels along the potential failure interface for both joints is extremely helpful; these residual stresses are mostly the forces of joint failure for both joints. Axisymmetric finite element analysis involves applying temperature along the whole joint as main parameter; the second parameter was changing the steel interlayer.
Journal of Al-Nahrain University Science, 2013
In this work the analytical and numerical methods were used to calculate the residual stresses in... more In this work the analytical and numerical methods were used to calculate the residual stresses induced in the joint due to the deference in the physical and mechanical properties of the materials, cooling from bonding temperature to room temperature. The residual stresses induced in graphite may be become too high that the joint break down so it takes as major stress in the joint. It was found that the residual stress is affected by the joint geometry and the nickel interlayer thickness. The analytical calculation of the residual thermal stresses in graphite/Inconel 600 and Inconel 600/nickel interlayer/Graphite multilayered was done for bonding temperature T bond =800 o Cwith various nickel foil thickness, it found that increasing nickel thickness reduce the thermal residual stresses inside the graphite. Numerical method by FEM was used to estimate the distribution of the maximum residual stresses (first principle stress) in the joint. The results indicate that increasing nickel thickness reduces the maximum tensile residual stress. So the joint thicknesses with graphite (5 mm) /Ni (0.1-0.2)mm/ Inconel600 (5 mm) are convenient.
Journal of Al-Nahrain University Science, 2017
In the present study, two gray cast iron specimens were diffusion bonded at the temperatures of 7... more In the present study, two gray cast iron specimens were diffusion bonded at the temperatures of 700, 750, 800, 850, and 900 °C, the furnace used atmosphericexperiment under a pressing load of 1 and 2 ton for 15, 30 and 60min. After diffusion bonding, shear test measurements of interface region were made. As a result, from the microstructural observations, a good bonding along the interface of the bonded couples were detected since the interface is free from voids and microcracks. To evaluate the bond strength, the shear test investigation was used. The actual bonded area was calculated by using a computer package called (Auto Cad 2006). The results shows that the bond strength increases with increasing the temperature and holding time. Fracturography of the interface was carried out by using optical microscope before and after the experiments. The microstructure results shows the formation of carbide. Its precipitation increases with increasing the bonding temperature and time.
School of Applied Sciences, University of Technology, Baghdad, Iraq Graphite is a very attractive... more School of Applied Sciences, University of Technology, Baghdad, Iraq Graphite is a very attractive candidate for copper-metal matrix composites. However, copper does not wet graphite, which makes the production of coppergraphite composites difficult. Because of the strong possibilities of these combinations in forming highly desirable composites, copper-carbon composites prepared by hot uniaxial pressure were investigated. The copper-carbon interface is of the samples was examined microscopically using optical microscopy. The observed microstructure at copper interface is composed of copper-carbon interaction layer. The adhesion between copper and graphite was achieved. However, there is no intimate contact between copper and graphite film at interface. To determine the diffusion of carbon through copper matrix by X-ray diffraction was used.
In the present study, gray cast iron was diffusion bonded under air atmosphere and in inert envir... more In the present study, gray cast iron was diffusion bonded under air atmosphere and in inert environment (argon). In air it was carried out at the temperatures of 700, 750, 800, 850, and 900 °C under UN pressing load of 1 and 2 ton for 15, 30 and 60min. After diffusion bonding, experimental studies were adopted. As a result, Vickers micro hardness testing was carried out to measure hardness distribution in gray cast iron joint. The results observed from Vickers micro hardness test show that the hardness increases with increasing bonding temperature due to formatio n of hard phased iron carbides (Fe3C)the maximum value were observed at 850°C for 60 min holding time under 2 ton is 310 HV. The microstructure results show the formation of carbide and the carbide precipitation increases with increasing the bonding temperature and time.
mechanical properties study of polycarbonate and other thermoplastic polymer, 2021
The polymeric materials in this study underwent mechanical tests (tensile test, impact resistance... more The polymeric materials in this study underwent mechanical tests (tensile test, impact resistance and hardness), which explained the use of polymeric materials in engineering and industrial applications that need good mechanical properties compared to metals, ceramic materials and woods, and this is a good thing because it is characterized by low cost and high efficiency with application performance In this study, the polycarbonate polymer was characterized by its high tensile strength in the event of breakage, but the elongation values decreased compared with the polypropylene and polyethylene polymers, which were characterized by high elongation at the expense of tensile strength, as the polycarbonate polymer acted as a brittle material as for resistance to shock, which reflected the amount of energy absorbed From the striking hammer, the impact resistance of high-density polyethylene increased compared to other polymers, as well as the hardness whose values were close to the three types of polymers used, which confirms the importance of these types in the application used in engineering.
Journal of Physics: Conference Series
Journal of Al-Nahrain University Science, 2010
Modeling of diffusion bonding of Inconel 600 /Pyrolytic Graphite and Inconel 600/steel interlayer... more Modeling of diffusion bonding of Inconel 600 /Pyrolytic Graphite and Inconel 600/steel interlayer/Pyrolytic Graphite is investigated in this research. Modeling implies utilization of ANSYS package to predict axisymmetric thermoelastic finite element analysis from the above materials. The model is used; to calculate thermal stresses induced across diffusion bonded joints. Investigating thermal stress levels along the potential failure interface for both joints is extremely helpful; these residual stresses are mostly the forces of joint failure for both joints. Axisymmetric finite element analysis involves applying temperature along the whole joint as main parameter; the second parameter was changing the steel interlayer.
Journal of Al-Nahrain University Science, 2013
In this work the analytical and numerical methods were used to calculate the residual stresses in... more In this work the analytical and numerical methods were used to calculate the residual stresses induced in the joint due to the deference in the physical and mechanical properties of the materials, cooling from bonding temperature to room temperature. The residual stresses induced in graphite may be become too high that the joint break down so it takes as major stress in the joint. It was found that the residual stress is affected by the joint geometry and the nickel interlayer thickness. The analytical calculation of the residual thermal stresses in graphite/Inconel 600 and Inconel 600/nickel interlayer/Graphite multilayered was done for bonding temperature T bond =800 o Cwith various nickel foil thickness, it found that increasing nickel thickness reduce the thermal residual stresses inside the graphite. Numerical method by FEM was used to estimate the distribution of the maximum residual stresses (first principle stress) in the joint. The results indicate that increasing nickel thickness reduces the maximum tensile residual stress. So the joint thicknesses with graphite (5 mm) /Ni (0.1-0.2)mm/ Inconel600 (5 mm) are convenient.
Journal of Al-Nahrain University Science, 2017
In the present study, two gray cast iron specimens were diffusion bonded at the temperatures of 7... more In the present study, two gray cast iron specimens were diffusion bonded at the temperatures of 700, 750, 800, 850, and 900 °C, the furnace used atmosphericexperiment under a pressing load of 1 and 2 ton for 15, 30 and 60min. After diffusion bonding, shear test measurements of interface region were made. As a result, from the microstructural observations, a good bonding along the interface of the bonded couples were detected since the interface is free from voids and microcracks. To evaluate the bond strength, the shear test investigation was used. The actual bonded area was calculated by using a computer package called (Auto Cad 2006). The results shows that the bond strength increases with increasing the temperature and holding time. Fracturography of the interface was carried out by using optical microscope before and after the experiments. The microstructure results shows the formation of carbide. Its precipitation increases with increasing the bonding temperature and time.
School of Applied Sciences, University of Technology, Baghdad, Iraq Graphite is a very attractive... more School of Applied Sciences, University of Technology, Baghdad, Iraq Graphite is a very attractive candidate for copper-metal matrix composites. However, copper does not wet graphite, which makes the production of coppergraphite composites difficult. Because of the strong possibilities of these combinations in forming highly desirable composites, copper-carbon composites prepared by hot uniaxial pressure were investigated. The copper-carbon interface is of the samples was examined microscopically using optical microscopy. The observed microstructure at copper interface is composed of copper-carbon interaction layer. The adhesion between copper and graphite was achieved. However, there is no intimate contact between copper and graphite film at interface. To determine the diffusion of carbon through copper matrix by X-ray diffraction was used.
In the present study, gray cast iron was diffusion bonded under air atmosphere and in inert envir... more In the present study, gray cast iron was diffusion bonded under air atmosphere and in inert environment (argon). In air it was carried out at the temperatures of 700, 750, 800, 850, and 900 °C under UN pressing load of 1 and 2 ton for 15, 30 and 60min. After diffusion bonding, experimental studies were adopted. As a result, Vickers micro hardness testing was carried out to measure hardness distribution in gray cast iron joint. The results observed from Vickers micro hardness test show that the hardness increases with increasing bonding temperature due to formatio n of hard phased iron carbides (Fe3C)the maximum value were observed at 850°C for 60 min holding time under 2 ton is 310 HV. The microstructure results show the formation of carbide and the carbide precipitation increases with increasing the bonding temperature and time.
mechanical properties study of polycarbonate and other thermoplastic polymer, 2021
The polymeric materials in this study underwent mechanical tests (tensile test, impact resistance... more The polymeric materials in this study underwent mechanical tests (tensile test, impact resistance and hardness), which explained the use of polymeric materials in engineering and industrial applications that need good mechanical properties compared to metals, ceramic materials and woods, and this is a good thing because it is characterized by low cost and high efficiency with application performance In this study, the polycarbonate polymer was characterized by its high tensile strength in the event of breakage, but the elongation values decreased compared with the polypropylene and polyethylene polymers, which were characterized by high elongation at the expense of tensile strength, as the polycarbonate polymer acted as a brittle material as for resistance to shock, which reflected the amount of energy absorbed From the striking hammer, the impact resistance of high-density polyethylene increased compared to other polymers, as well as the hardness whose values were close to the three types of polymers used, which confirms the importance of these types in the application used in engineering.
Journal of Physics: Conference Series