mustafa aksoy - Academia.edu (original) (raw)

Papers by mustafa aksoy

Protection of Metals and Physical Chemistry of Surfaces, 2009

The corrosion behavior of ferritic stainless steel containing 1 wt, % Mo was investigated using a... more The corrosion behavior of ferritic stainless steel containing 1 wt, % Mo was investigated using an AC impedance technique and the mass loss method. The alloys were produced by casting and forging. They were classified into three groups: unhomogenized, homogenized for 30 minutes and homogenized for 180 minutes. Mass loss tests were carried out on samples homogenized for 180 minutes. The corrosion tests were performed in 0.1 M H 2 SO 4 and 0.3 M HCl acid solutions. SEM investigations were performed on the surface of samples exposed to corrosion for 30 and 360 minutes. The results were compared with results obtained from experiments performed on unalloyed ferritic stainless steel. Molybdenum (Mo) and homogenization heat treatment were found to have a beneficial effect on corrosion behavior of ferritic stainless steel in these solutions.

Journal of Materials Processing Technology, 2006

The main aim of this research was to investigate the influence of temperature (in the range 20-20... more The main aim of this research was to investigate the influence of temperature (in the range 20-200 • C) on the abrasive wear behaviour of a 2124 Al/SiC composite produced by powder metallurgy techniques. Abrasive wear tests were conducted at constant distance and 10 N load using pin-on-disk apparatus. Some specimen taken from the composite materials were artificially aged (T6) to determine ageing effects. At the last stage of the study, worn surfaces and the subsurfaces were examined by using SEM, EDS and optical microscopy. Wear test results obtained at all test temperatures showed that the weight loss of the aged specimens was less than that of the non-aged specimens. It was also observed that the better wear resistance was seen for specimens worn at RT both the aged and non-aged specimens. There was no (or little) net change in wear rate for the test temperature above 50 • C both the aged and non-aged specimens. Because of contact between SiC particles in the composite material and abrasive paper, broken or loosened hard SiC particulates embedded to the soft layer under worn surface which observed at 50-200 • C, caused an increase in strength of surface of the composite specimens and so resulted little change in wear rate.

2014 IEEE Geoscience and Remote Sensing Symposium, 2014

Many quantities describing ice sheet dynamics can be measured via remote sensing. However, subsur... more Many quantities describing ice sheet dynamics can be measured via remote sensing. However, subsurface ice sheet temperature, a very important parameter which determines in part internal deformation and ice flow, is not currently measured remotely. Direct knowledge is available only through measurements from a small number of boreholes. This paper presents the concept of utilizing microwave radiometry in the 0.5-2GHz frequency band to probe subsurface ice sheet temperatures. Ice sheet geophysical properties and the resulting microwave emission are reviewed, and an initial retrieval algorithm for subsurface ice sheet temperatures is described. Finally an ultrawideband radiometer design to realize the proposed measurements is summarized.

Journal of Materials Science, 2014

The effect of nickel on the microstructure and mechanical properties of a die-cast Al-Mg-Si-Mn al... more The effect of nickel on the microstructure and mechanical properties of a die-cast Al-Mg-Si-Mn alloy has been investigated. The results show that the presence of Ni in the alloy promotes the formation of Ni-rich intermetallics. These occur consistently during solidification in the die-cast Al-Mg-Si-Mn alloy across different levels of Ni content. The Ni-rich intermetallics exhibit dendritic morphology during the primary solidification and lamellar morphology during the eutectic solidification stage. Ni was found to be always associated with iron, forming AlFeMnSiNi intermetallics and no Al 3 Ni intermetallic was observed when Ni concentrations were up to 2.06wt% in the alloy. Although with different morphologies, the Ni-rich intermetallics were identified as the same AlFeMnSiNi phase bearing a typical composition of Al [100-140] (Fe,Mn) [2-7] SiNi [4-9]. With increasing Ni content, the spacing of the -Al-Mg 2 Si eutectic phase was enlarged in the Al-Mg-Si-Mn alloy. The addition of Ni to the alloy resulted in a slight increase in the yield strength, but a significant decrease in the elongation. The ultimate tensile strength (UTS) increased slightly from 300 MPa to 320MPa when a small amount (e.g., 0.16wt. %) of Ni was added to the alloy, but further increase of the Ni content resulted in a decrease of the UTS.

Materials Science and Technology, 2003

ABSTRACT The wear mechanisms of iron based metal matrix composites and the wear behaviours of var... more ABSTRACT The wear mechanisms of iron based metal matrix composites and the wear behaviours of various microstructures were systematically studied by dry sliding wear testing and SEM examination. The experimental results show that three dominant wear mechanisms appeared in succession with increasing normal load during dry sliding. The transition of the wear mechanisms depended mainly upon the conditions of testing, and additionally it was seen that changes in microstructure of the steel had no marked effect on the transition. In the case of mild wear, no obvious differences in wear volume were found for the various microstructures. However, considerable differences in the wear volumes were observed under conditions of severe wear characterised by adhesion and delamination. The experimental results also indicate that the differences in wear resistance of the various microstructures were caused by differences in microstructural thermal stability, resistance to plastic deformation, resistance to nucleation and propagation of microcracks and especially by differences in energy consumption in these layers during wear.

Gazi Universitesi Fen Bilimleri Dergisi Part C Tasarım Ve Teknoloji, 2013

In this study, Boron Nitride Nanotubes (BNNTs) were synthesized using a ball-milling and annealin... more In this study, Boron Nitride Nanotubes (BNNTs) were synthesized using a ball-milling and annealing method. Starting powder was used as the amorphous boron powder and in a planetary ball mill (FritschPulverisette 7 Premium Line) was ball milled for 2 hours under nitrogen atmosphere. After milling process, obtained powders were annealed under NH3+N2 flow at 1300ᴼC for different time as 2,4,6 hrs in tube furnace

Resources, Conservation and Recycling, 1995

Coal combustion fly ash is produced as a byproduct in huge amounts from pulverized coal-fired pow... more Coal combustion fly ash is produced as a byproduct in huge amounts from pulverized coal-fired power plants. Waste plastics from packaging materials and other uses are recovered in large quantities. An investigation has been conducted to produce a new building material from fly ash and polyethylene. The work was carded out with two typical coal fly ashes and polyethylene bags. The tensile strengths and the chemical resistance of the materials, in addition to the effect of temperature were examined. Characterization of these materials was also studied by means of XRD, IR and SEM techniques. The tensile strengths of the materials range from 0.92 to 2.62 kp/rnm 2. When the ratio of fly ash is low, better results were obtained. There was no significant loss in weight in solutions of NaOH (5%), CH~COOH (5%), C2HsOH (95%), H2SO 4 (5%) and H20.

Journal of Materials Processing Technology, 2005

Metal matrix composites (MMC) have become a large leading material in composite materials and par... more Metal matrix composites (MMC) have become a large leading material in composite materials and particle reinforced aluminium MMCs have received considerable attention due to their excellent engineering properties. These materials are known as the difficult-to-machine materials, because of the hardness and abrasive nature of reinforcement element like silicon carbide (SiC) particles. In this study, homogenised 5% SiC-p aluminium MMC material was selected for experimental investigation of tool wear and surface roughness. Two types of K10 cutting tool (uncoated and TiN-coated) were used at different cutting speeds (50, 100 and 150 m/min), feed rates (0.1, 0.2 and 0.3 mm/rev) and depths of cut (0.5, 1 and 1.5 mm). In dry turning condition, tool wear was mainly affected by cutting speed, increased with increasing cutting speed. Tool wear was lower when coated cutting tool was used in comparison to uncoated one. Surface roughness influenced with cutting speed and feed rate. Higher cutting speeds and lower feed rates produced better surface quality.

International Journal of Fatigue, 1989

CORROSION, 2009

Electrochemical impedance spectroscopy (EIS) is a powerful, rapid, and accurate nondestructive me... more Electrochemical impedance spectroscopy (EIS) is a powerful, rapid, and accurate nondestructive method for the evaluation of a wide range of materials. In this work, the corrosion behavior of some ferritic stainless steels was studied in 0.3 M hydrochloric acid (HCl) acid solution. The samples were obtained from casting and forging. Stainless steels were unalloyed and alloyed with about 1 wt% Ti, V, and Nb. The steels were exposed to different heat treatments, but heat treatment was not applied to the first group samples. The second and third group samples were rapidly cooled after annealing at 1,100°C for 30 min and 180 min, respectively. Corrosion resistance was calculated using the Stearn-Geary equation, and scanning electron microscopy (SEM) was performed. According to electrochemical impedance spectroscopy (EIS), the corrosion resistance increased by the alloying element. Heat treatment has a critical effect on the corrosion resistance. The best corrosion resistance was observed from ferritic stainless steel with Nb-exposed homogenization for 180 min.

uvt.ulakbim.gov.tr

... Page 2. S. Yıldız ve O. Keleştemur 758 1. Giriş ... Daha önce pasif hale gelmiş olan betonarm... more ... Page 2. S. Yıldız ve O. Keleştemur 758 1. Giriş ... Daha önce pasif hale gelmiş olan betonarme demirlerinin üzerinde bulunan pasif tabaka yer yer bozulur ve bu bölgede, çukurcuklar oluşturarak kendini gösteren pitting tipi korozyon olayı başlar. ...

International Journal of …, 2009

In this study, corrosion behavior of reinforcing steel embedded in concrete samples obtained from... more In this study, corrosion behavior of reinforcing steel embedded in concrete samples obtained from CEM II /B-M 32.5 R Portland cement type which has been taken from various factories in order to determine effect of oxide compositions in the cement has been examined. For this purpose, the mixture ratio of concrete samples has been prepared according to ACI 211.1 and the same type and amount of materials have been used for the samples. The unique difference among samples was CEM II /B-M 32.5 R Portland cements on various producing center. The corrosion experiments were conducted in two stages. In the first stage, the corrosion potential of steels in the concrete was measured every day for a period of 90 days in accordance with ASTMC 876 standard. In the second stage, anodic and cathodic polarization values of these steels were obtained and then the corrosion currents were determined with the aid of cathodic polarization curves. As a result of this study, it was found that corrosion rate of reinforcing steel embedded in concrete affected with the change of oxide compositions in the cement.

Corrosion Engineering, Science and Technology, 2009

Corrosion behaviours of stainless steel alloys containing corrosion resistant elements were inves... more Corrosion behaviours of stainless steel alloys containing corrosion resistant elements were investigated. Ferritic stainless steel electrodes were synthesised by the application of a scan rate of 1 mV s 21. Stainless steels were unalloyed and alloyed with approximate 1 wt-% Ti, V and Nb elements. The samples were obtained from casting and forging. The steels were exposed to different heat treatments. Heat treatment was not applied to the first group of samples. The second and the third group of samples were rapidly cooled after annealing at 1100uC for 30 and 180 min respectively. The corrosion performances of ferritic stainless steels were investigated in 0?1 M H 2 SO 4 solution, by use of electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) investigations were performed. Scanning electron microscopy micrographs showed generalised pitting on the surface. Corrosion resistance was calculated by Stearn-Geary equation. It was determined that titanium has the best effect on the corrosion resistance of ferritic stainless steels homogenised for 180 min.

Journal of Materials Processing Technology, 2006

Joining characteristic of SiC particulate reinforced aluminum metal matrix composites (MMCs) with... more Joining characteristic of SiC particulate reinforced aluminum metal matrix composites (MMCs) with pure aluminum were investigated by diffusion bonding process. The joining quality of the Al/SiCp MMCs was studied to determine the influences of SiCp particulates with homogenization and age hardening on bonding properties. The experimental results indicate that the application of aging before and after diffusion bonding decreases SiC particulate accumulation, and increases other elemental concentration at interface. Especially, the application of aging treatment before the diffusion bonding of Al/SiCp MMCs to pure Al, increased Cu% concentration at interface which treats as the insert alloy.

Journal of materials processing …, 2003

... Finally, the grain boundaries on the interface migrate and grain growth occurs. ... be expect... more ... Finally, the grain boundaries on the interface migrate and grain growth occurs. ... be expected from the surfaces of the nodules which have already a spherical shape. ... an increase in time and bonding temperature can produce complete dissolution of the graphite flakes, especially ...

International Journal of Minerals, Metallurgy and Materials, 2009

Dual-phase (DP) steels with different martensite contents were obtained by appropriate heat treat... more Dual-phase (DP) steels with different martensite contents were obtained by appropriate heat treatment of an SAE1010 structural carbon steel, which was cheap and widely used in the construction industry. The corrosion behavior of DP steels in concrete was investigated under various tempering conditions. Intercritical annealing heat treatment was applied to the reinforcing steel to obtain DP steels with different contents of martensite. These DP steels were tempered at 200, 300, and 400°C for 45 min and then cooled to room temperature. Corrosion experiments were conducted in two stages. In the first stage, the corrosion potential of DP steels embedded in concrete was measured every day for a period of 30 d based on the ASTM C 876 standard. In the second stage, the anodic and cathodic polarization values of these steels were obtained and subsequently the corrosion currents were determined with the aid of cathodic polarization curves. It was observed that the amount of second phase had a definite effect on the corrosion behavior of the DP steel embedded in concrete. As a result of this study, it is found that the corrosion rate of the DP steel increases with an increase in the amount of martensite.

Protection of Metals and Physical Chemistry of Surfaces, 2009

The corrosion behavior of ferritic stainless steel containing 1 wt, % Mo was investigated using a... more The corrosion behavior of ferritic stainless steel containing 1 wt, % Mo was investigated using an AC impedance technique and the mass loss method. The alloys were produced by casting and forging. They were classified into three groups: unhomogenized, homogenized for 30 minutes and homogenized for 180 minutes. Mass loss tests were carried out on samples homogenized for 180 minutes. The corrosion tests were performed in 0.1 M H 2 SO 4 and 0.3 M HCl acid solutions. SEM investigations were performed on the surface of samples exposed to corrosion for 30 and 360 minutes. The results were compared with results obtained from experiments performed on unalloyed ferritic stainless steel. Molybdenum (Mo) and homogenization heat treatment were found to have a beneficial effect on corrosion behavior of ferritic stainless steel in these solutions.

Journal of Materials Processing Technology, 2006

The main aim of this research was to investigate the influence of temperature (in the range 20-20... more The main aim of this research was to investigate the influence of temperature (in the range 20-200 • C) on the abrasive wear behaviour of a 2124 Al/SiC composite produced by powder metallurgy techniques. Abrasive wear tests were conducted at constant distance and 10 N load using pin-on-disk apparatus. Some specimen taken from the composite materials were artificially aged (T6) to determine ageing effects. At the last stage of the study, worn surfaces and the subsurfaces were examined by using SEM, EDS and optical microscopy. Wear test results obtained at all test temperatures showed that the weight loss of the aged specimens was less than that of the non-aged specimens. It was also observed that the better wear resistance was seen for specimens worn at RT both the aged and non-aged specimens. There was no (or little) net change in wear rate for the test temperature above 50 • C both the aged and non-aged specimens. Because of contact between SiC particles in the composite material and abrasive paper, broken or loosened hard SiC particulates embedded to the soft layer under worn surface which observed at 50-200 • C, caused an increase in strength of surface of the composite specimens and so resulted little change in wear rate.

2014 IEEE Geoscience and Remote Sensing Symposium, 2014

Many quantities describing ice sheet dynamics can be measured via remote sensing. However, subsur... more Many quantities describing ice sheet dynamics can be measured via remote sensing. However, subsurface ice sheet temperature, a very important parameter which determines in part internal deformation and ice flow, is not currently measured remotely. Direct knowledge is available only through measurements from a small number of boreholes. This paper presents the concept of utilizing microwave radiometry in the 0.5-2GHz frequency band to probe subsurface ice sheet temperatures. Ice sheet geophysical properties and the resulting microwave emission are reviewed, and an initial retrieval algorithm for subsurface ice sheet temperatures is described. Finally an ultrawideband radiometer design to realize the proposed measurements is summarized.

Journal of Materials Science, 2014

The effect of nickel on the microstructure and mechanical properties of a die-cast Al-Mg-Si-Mn al... more The effect of nickel on the microstructure and mechanical properties of a die-cast Al-Mg-Si-Mn alloy has been investigated. The results show that the presence of Ni in the alloy promotes the formation of Ni-rich intermetallics. These occur consistently during solidification in the die-cast Al-Mg-Si-Mn alloy across different levels of Ni content. The Ni-rich intermetallics exhibit dendritic morphology during the primary solidification and lamellar morphology during the eutectic solidification stage. Ni was found to be always associated with iron, forming AlFeMnSiNi intermetallics and no Al 3 Ni intermetallic was observed when Ni concentrations were up to 2.06wt% in the alloy. Although with different morphologies, the Ni-rich intermetallics were identified as the same AlFeMnSiNi phase bearing a typical composition of Al [100-140] (Fe,Mn) [2-7] SiNi [4-9]. With increasing Ni content, the spacing of the -Al-Mg 2 Si eutectic phase was enlarged in the Al-Mg-Si-Mn alloy. The addition of Ni to the alloy resulted in a slight increase in the yield strength, but a significant decrease in the elongation. The ultimate tensile strength (UTS) increased slightly from 300 MPa to 320MPa when a small amount (e.g., 0.16wt. %) of Ni was added to the alloy, but further increase of the Ni content resulted in a decrease of the UTS.

Materials Science and Technology, 2003

ABSTRACT The wear mechanisms of iron based metal matrix composites and the wear behaviours of var... more ABSTRACT The wear mechanisms of iron based metal matrix composites and the wear behaviours of various microstructures were systematically studied by dry sliding wear testing and SEM examination. The experimental results show that three dominant wear mechanisms appeared in succession with increasing normal load during dry sliding. The transition of the wear mechanisms depended mainly upon the conditions of testing, and additionally it was seen that changes in microstructure of the steel had no marked effect on the transition. In the case of mild wear, no obvious differences in wear volume were found for the various microstructures. However, considerable differences in the wear volumes were observed under conditions of severe wear characterised by adhesion and delamination. The experimental results also indicate that the differences in wear resistance of the various microstructures were caused by differences in microstructural thermal stability, resistance to plastic deformation, resistance to nucleation and propagation of microcracks and especially by differences in energy consumption in these layers during wear.

Gazi Universitesi Fen Bilimleri Dergisi Part C Tasarım Ve Teknoloji, 2013

In this study, Boron Nitride Nanotubes (BNNTs) were synthesized using a ball-milling and annealin... more In this study, Boron Nitride Nanotubes (BNNTs) were synthesized using a ball-milling and annealing method. Starting powder was used as the amorphous boron powder and in a planetary ball mill (FritschPulverisette 7 Premium Line) was ball milled for 2 hours under nitrogen atmosphere. After milling process, obtained powders were annealed under NH3+N2 flow at 1300ᴼC for different time as 2,4,6 hrs in tube furnace

Resources, Conservation and Recycling, 1995

Coal combustion fly ash is produced as a byproduct in huge amounts from pulverized coal-fired pow... more Coal combustion fly ash is produced as a byproduct in huge amounts from pulverized coal-fired power plants. Waste plastics from packaging materials and other uses are recovered in large quantities. An investigation has been conducted to produce a new building material from fly ash and polyethylene. The work was carded out with two typical coal fly ashes and polyethylene bags. The tensile strengths and the chemical resistance of the materials, in addition to the effect of temperature were examined. Characterization of these materials was also studied by means of XRD, IR and SEM techniques. The tensile strengths of the materials range from 0.92 to 2.62 kp/rnm 2. When the ratio of fly ash is low, better results were obtained. There was no significant loss in weight in solutions of NaOH (5%), CH~COOH (5%), C2HsOH (95%), H2SO 4 (5%) and H20.

Journal of Materials Processing Technology, 2005

Metal matrix composites (MMC) have become a large leading material in composite materials and par... more Metal matrix composites (MMC) have become a large leading material in composite materials and particle reinforced aluminium MMCs have received considerable attention due to their excellent engineering properties. These materials are known as the difficult-to-machine materials, because of the hardness and abrasive nature of reinforcement element like silicon carbide (SiC) particles. In this study, homogenised 5% SiC-p aluminium MMC material was selected for experimental investigation of tool wear and surface roughness. Two types of K10 cutting tool (uncoated and TiN-coated) were used at different cutting speeds (50, 100 and 150 m/min), feed rates (0.1, 0.2 and 0.3 mm/rev) and depths of cut (0.5, 1 and 1.5 mm). In dry turning condition, tool wear was mainly affected by cutting speed, increased with increasing cutting speed. Tool wear was lower when coated cutting tool was used in comparison to uncoated one. Surface roughness influenced with cutting speed and feed rate. Higher cutting speeds and lower feed rates produced better surface quality.

International Journal of Fatigue, 1989

CORROSION, 2009

Electrochemical impedance spectroscopy (EIS) is a powerful, rapid, and accurate nondestructive me... more Electrochemical impedance spectroscopy (EIS) is a powerful, rapid, and accurate nondestructive method for the evaluation of a wide range of materials. In this work, the corrosion behavior of some ferritic stainless steels was studied in 0.3 M hydrochloric acid (HCl) acid solution. The samples were obtained from casting and forging. Stainless steels were unalloyed and alloyed with about 1 wt% Ti, V, and Nb. The steels were exposed to different heat treatments, but heat treatment was not applied to the first group samples. The second and third group samples were rapidly cooled after annealing at 1,100°C for 30 min and 180 min, respectively. Corrosion resistance was calculated using the Stearn-Geary equation, and scanning electron microscopy (SEM) was performed. According to electrochemical impedance spectroscopy (EIS), the corrosion resistance increased by the alloying element. Heat treatment has a critical effect on the corrosion resistance. The best corrosion resistance was observed from ferritic stainless steel with Nb-exposed homogenization for 180 min.

uvt.ulakbim.gov.tr

... Page 2. S. Yıldız ve O. Keleştemur 758 1. Giriş ... Daha önce pasif hale gelmiş olan betonarm... more ... Page 2. S. Yıldız ve O. Keleştemur 758 1. Giriş ... Daha önce pasif hale gelmiş olan betonarme demirlerinin üzerinde bulunan pasif tabaka yer yer bozulur ve bu bölgede, çukurcuklar oluşturarak kendini gösteren pitting tipi korozyon olayı başlar. ...

International Journal of …, 2009

In this study, corrosion behavior of reinforcing steel embedded in concrete samples obtained from... more In this study, corrosion behavior of reinforcing steel embedded in concrete samples obtained from CEM II /B-M 32.5 R Portland cement type which has been taken from various factories in order to determine effect of oxide compositions in the cement has been examined. For this purpose, the mixture ratio of concrete samples has been prepared according to ACI 211.1 and the same type and amount of materials have been used for the samples. The unique difference among samples was CEM II /B-M 32.5 R Portland cements on various producing center. The corrosion experiments were conducted in two stages. In the first stage, the corrosion potential of steels in the concrete was measured every day for a period of 90 days in accordance with ASTMC 876 standard. In the second stage, anodic and cathodic polarization values of these steels were obtained and then the corrosion currents were determined with the aid of cathodic polarization curves. As a result of this study, it was found that corrosion rate of reinforcing steel embedded in concrete affected with the change of oxide compositions in the cement.

Corrosion Engineering, Science and Technology, 2009

Corrosion behaviours of stainless steel alloys containing corrosion resistant elements were inves... more Corrosion behaviours of stainless steel alloys containing corrosion resistant elements were investigated. Ferritic stainless steel electrodes were synthesised by the application of a scan rate of 1 mV s 21. Stainless steels were unalloyed and alloyed with approximate 1 wt-% Ti, V and Nb elements. The samples were obtained from casting and forging. The steels were exposed to different heat treatments. Heat treatment was not applied to the first group of samples. The second and the third group of samples were rapidly cooled after annealing at 1100uC for 30 and 180 min respectively. The corrosion performances of ferritic stainless steels were investigated in 0?1 M H 2 SO 4 solution, by use of electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) investigations were performed. Scanning electron microscopy micrographs showed generalised pitting on the surface. Corrosion resistance was calculated by Stearn-Geary equation. It was determined that titanium has the best effect on the corrosion resistance of ferritic stainless steels homogenised for 180 min.

Journal of Materials Processing Technology, 2006

Joining characteristic of SiC particulate reinforced aluminum metal matrix composites (MMCs) with... more Joining characteristic of SiC particulate reinforced aluminum metal matrix composites (MMCs) with pure aluminum were investigated by diffusion bonding process. The joining quality of the Al/SiCp MMCs was studied to determine the influences of SiCp particulates with homogenization and age hardening on bonding properties. The experimental results indicate that the application of aging before and after diffusion bonding decreases SiC particulate accumulation, and increases other elemental concentration at interface. Especially, the application of aging treatment before the diffusion bonding of Al/SiCp MMCs to pure Al, increased Cu% concentration at interface which treats as the insert alloy.

Journal of materials processing …, 2003

... Finally, the grain boundaries on the interface migrate and grain growth occurs. ... be expect... more ... Finally, the grain boundaries on the interface migrate and grain growth occurs. ... be expected from the surfaces of the nodules which have already a spherical shape. ... an increase in time and bonding temperature can produce complete dissolution of the graphite flakes, especially ...

International Journal of Minerals, Metallurgy and Materials, 2009

Dual-phase (DP) steels with different martensite contents were obtained by appropriate heat treat... more Dual-phase (DP) steels with different martensite contents were obtained by appropriate heat treatment of an SAE1010 structural carbon steel, which was cheap and widely used in the construction industry. The corrosion behavior of DP steels in concrete was investigated under various tempering conditions. Intercritical annealing heat treatment was applied to the reinforcing steel to obtain DP steels with different contents of martensite. These DP steels were tempered at 200, 300, and 400°C for 45 min and then cooled to room temperature. Corrosion experiments were conducted in two stages. In the first stage, the corrosion potential of DP steels embedded in concrete was measured every day for a period of 30 d based on the ASTM C 876 standard. In the second stage, the anodic and cathodic polarization values of these steels were obtained and subsequently the corrosion currents were determined with the aid of cathodic polarization curves. It was observed that the amount of second phase had a definite effect on the corrosion behavior of the DP steel embedded in concrete. As a result of this study, it is found that the corrosion rate of the DP steel increases with an increase in the amount of martensite.