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Kwang-Jin Lee
Carbon Materials Application R&D Group, Korea Institute of Industrial Technology, Jeonju 54853, Korea

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Journal article
Published: 19 December 2020 in Applied Sciences
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In the existing automobile manufacturing process, metal inert gas (MIG) and tungsten inert gas (TIG) welding are mainly used. These welding methods are fusion welding, and the heat input in the welding area is very high. Therefore, the deformation of the base material is large, and the residual stress in the vicinity of the welded area is high, resulting in the problem of reduced mechanical strength. In this study, friction stir welding (FSW) was applied to the welding process of the structure constituting the battery frame of a newly developing electric vehicle to compensate for this problem. The welded part is the fillet joint of the side frame and the bottom frame, and experiments and numerical analysis were performed on the welding deformation and residual stress of the full frame structure. A specially manufactured angle head was used for friction stir welding of the fillet joint of extruded type aluminum, not the existing solid type. The optimum process was derived through experiments, and the temperature of the welding center was derived through test correlation between the value of measured temperature and the finite element model. The final deformation result was verified by comparing it with the measured value using a dial indicator. It is expected that the proposed thermal elasto-plastic analysis method will reduce the testing period and the cost of the manufacturing process and increase productivity.

ACS Style

Hwanjin Kim; Kwangjin Lee; Jaewoong Kim; Changyeon Lee; Yoonchul Jung; Sungwook Kang. A Study on the Friction Stir Welding Experiment and Simulation of the Fillet Joint of Extruded Aluminum Material of Electric Vehicle Frame. Applied Sciences 2020, 10, 9103 .

AMA Style

Hwanjin Kim, Kwangjin Lee, Jaewoong Kim, Changyeon Lee, Yoonchul Jung, Sungwook Kang. A Study on the Friction Stir Welding Experiment and Simulation of the Fillet Joint of Extruded Aluminum Material of Electric Vehicle Frame. Applied Sciences. 2020; 10 (24):9103.

Chicago/Turabian Style

Hwanjin Kim; Kwangjin Lee; Jaewoong Kim; Changyeon Lee; Yoonchul Jung; Sungwook Kang. 2020. "A Study on the Friction Stir Welding Experiment and Simulation of the Fillet Joint of Extruded Aluminum Material of Electric Vehicle Frame." Applied Sciences 10, no. 24: 9103.

Original article
Published: 30 April 2020 in Journal of Mechanical Science and Technology
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The microstructure and mechanical properties of friction stir welded boron steel in butt joint configuration are experimentally studied. Two different friction stir welding (FSW) parameter combinations are used to successfully fabricate butt joints. Microstructural analysis exhibites that the stir zone (SZ) primarily consists of fine lath martensite, while the thermo-mechanically affected zone (TMAZ) comprises bainitic ferrite and granular bainite with a small amount of martensite. The presence of granular bainite in TMAZ suggests that alloying composition affects the phase transformation. The formation of recrystallized structures with lath martensites and high dislocation density in the SZ significantly enhance the hardness of the joints compared to that of the base metal. The results of the present study suggest that FSW can be used as a method for local hardening of structural components made of boron steels, without complicated heating and rapid cooling of a conventional hot stamping process.

ACS Style

Hrishikesh Das; Mounarik Mondal; Sung-Tae Hong; Kwang-Jin Lee; Kinnor Chattopadhyay. Microstructure and mechanical properties evaluation of friction stir welded boron steel. Journal of Mechanical Science and Technology 2020, 34, 2011 -2017.

AMA Style

Hrishikesh Das, Mounarik Mondal, Sung-Tae Hong, Kwang-Jin Lee, Kinnor Chattopadhyay. Microstructure and mechanical properties evaluation of friction stir welded boron steel. Journal of Mechanical Science and Technology. 2020; 34 (5):2011-2017.

Chicago/Turabian Style

Hrishikesh Das; Mounarik Mondal; Sung-Tae Hong; Kwang-Jin Lee; Kinnor Chattopadhyay. 2020. "Microstructure and mechanical properties evaluation of friction stir welded boron steel." Journal of Mechanical Science and Technology 34, no. 5: 2011-2017.

Journal article
Published: 13 September 2019 in Applied Sciences
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With the rise of electric vehicles, the use of battery modules, which are key units that drive vehicles, is increasing. The battery housing is the final form of a battery system mounted on electric vehicles, and is generally made of aluminum alloys, located at the bottom of the vehicle. The aluminum housing has a special shape to accommodate the battery module and is produced by welding extruded panels. This study applied friction stir welding (FSW) to weld 2.5 mm thin aluminum plates in order to improve the weldability and productivity. To increase productivity, we compared the mechanical properties after performing experiments under various FSW conditions. As a result, it was possible to derive speed-enabling welding conditions that can improve productivity without decreasing tensile strength. Deformation occurred in the structure during welding, causing gaps in the structure. Since these gaps have a significant influence on the degradation of mechanical properties after welding, the welding deformation at each step of welding must be calculated and reflected in the process. This study used the inherent strain method to calculate the deformation of each step of welding to apply automatic welding, and reduced the analysis time to 1/30 compared to the thermal elasto-plastic analysis method. Finally, this study verified the validity of the analysis method by comparing the experimental results with the numerical results using the inherent strain method.

ACS Style

Sungwook Kang; Jaewoong Kim; Youngjae Jang; Kwangjin Lee. Welding Deformation Analysis, Using an Inherent Strain Method for Friction Stir Welded Electric Vehicle Aluminum Battery Housing, Considering Productivity. Applied Sciences 2019, 9, 3848 .

AMA Style

Sungwook Kang, Jaewoong Kim, Youngjae Jang, Kwangjin Lee. Welding Deformation Analysis, Using an Inherent Strain Method for Friction Stir Welded Electric Vehicle Aluminum Battery Housing, Considering Productivity. Applied Sciences. 2019; 9 (18):3848.

Chicago/Turabian Style

Sungwook Kang; Jaewoong Kim; Youngjae Jang; Kwangjin Lee. 2019. "Welding Deformation Analysis, Using an Inherent Strain Method for Friction Stir Welded Electric Vehicle Aluminum Battery Housing, Considering Productivity." Applied Sciences 9, no. 18: 3848.

Journal article
Published: 30 April 2019 in Journal of Welding and Joining
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ACS Style

Young-Bin Lim; Kwang-Jin Lee. Microtexture and Microstructural Evolution of Friction Stir Welded AA5052-H32 Joints. Journal of Welding and Joining 2019, 37, 35 -40.

AMA Style

Young-Bin Lim, Kwang-Jin Lee. Microtexture and Microstructural Evolution of Friction Stir Welded AA5052-H32 Joints. Journal of Welding and Joining. 2019; 37 (2):35-40.

Chicago/Turabian Style

Young-Bin Lim; Kwang-Jin Lee. 2019. "Microtexture and Microstructural Evolution of Friction Stir Welded AA5052-H32 Joints." Journal of Welding and Joining 37, no. 2: 35-40.

Journal article
Published: 19 April 2019 in Metals
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This paper investigated the microstructure and mechanical properties of a friction-stir-welded beryllium-copper alloy, which is difficult to weld with conventional fusion welding processes. Friction stir welding (FSW) was successfully conducted with a tungsten-carbide (WC) tool. Sound joints without defects were obtained with a tool rotational speed of 700 RPM and tool travel speed of 60 mm/min. A post-weld heat treatment (PWHT) of the FSW joints was performed to analyze the evolution of the microstructure at 315 °C for a half, one, two, three, four, five and eight hours, respectively. The microstructures of the joints were observed using an optical microscope (OM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Observed softening of microstructure is suggested to be due to the dissolution of the strengthening precipitates during the FSW process, whereas the strength of the joints was recovered via the formation of the CuBe (γ′) phase during the post-weld heat treatment. However, the strength was decreased upon an excessive post-weld heat treatment exceeding three hours. It is considered that the formation of the γ phase and the coarse γ′ phase contributed to the reduction in the strength.

ACS Style

Yeongseok Lim; Kwangjin Lee; Sangdon Moon. Effects of a Post-Weld Heat Treatment on the Mechanical Properties and Microstructure of a Friction-Stir-Welded Beryllium-Copper Alloy. Metals 2019, 9, 461 .

AMA Style

Yeongseok Lim, Kwangjin Lee, Sangdon Moon. Effects of a Post-Weld Heat Treatment on the Mechanical Properties and Microstructure of a Friction-Stir-Welded Beryllium-Copper Alloy. Metals. 2019; 9 (4):461.

Chicago/Turabian Style

Yeongseok Lim; Kwangjin Lee; Sangdon Moon. 2019. "Effects of a Post-Weld Heat Treatment on the Mechanical Properties and Microstructure of a Friction-Stir-Welded Beryllium-Copper Alloy." Metals 9, no. 4: 461.

Journal article
Published: 01 May 2018 in Materials Characterization
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The microstructure and mechanical properties of friction stir spot welding of ultrahigh strength dual phase (DP) and complex phase (DP) steels are compared based on the experimental results. For both DP and CP steels, FSSW joints are successfully fabricated using the same process parameter set. While the microstructure of joints are characterized in detail using scanning electron microscopy, electron back scattered diffraction, and transmission electron microscopy, the mechanical property of joints are evaluated by shear tensile tests. The result of the microstructural analysis shows that the stir zone (SZ) of CP steel mainly consists of bainite and martensite, while no bainite is identified in the SZ of DP steel. The existence of bainite in the SZ of CP steel suggests that the cooling rate, which is nearly identical for both CP and DP steels, was not fast enough to suppress the effect of the alloying composition, particularly that of Mn, on the phase transformation. The result of the present study contributes to the development of solid state joining process of the ultrahigh strength steels.

ACS Style

Hrishikesh Das; Mounarik Mondal; Sung-Tae Hong; Yeongseok Lim; Kwang-Jin Lee. Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels. Materials Characterization 2018, 139, 428 -436.

AMA Style

Hrishikesh Das, Mounarik Mondal, Sung-Tae Hong, Yeongseok Lim, Kwang-Jin Lee. Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels. Materials Characterization. 2018; 139 ():428-436.

Chicago/Turabian Style

Hrishikesh Das; Mounarik Mondal; Sung-Tae Hong; Yeongseok Lim; Kwang-Jin Lee. 2018. "Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels." Materials Characterization 139, no. : 428-436.

Research article
Published: 03 April 2018 in Advances in Materials Science and Engineering
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This study was performed to investigate both the residual stress distribution and the effect of the residual stress formed at the welding region on the mechanical properties of the friction stir welded joints with 409L stainless steel sheets. Residual stress measurement with hole-drilling method; mechanical property evaluation including tensile test, Charpy impact test, and fatigue test; and microstructure observation were conducted. It has got no residual stresses to speak of at the center region of the stir zone because the stored stresses are released in the process of the dynamic recrystallization, while a small quantity of compressive residual stresses is formed at the surface region of the stir zone because of strong compression reaction by the tool shoulder. A considerable amount of compressive residual stresses is formed at the thermomechanical affected zone because of the synergy between the thermal expansion due to the heat conduction from the stir zone and mechanical compression by the tool. The formation of residual stresses shows a similar tendency between the advancing side and the retreating side. Both the mitigation of residual stress in the stir zone and the formation of compressive residual stress in the thermomechanical affected zone contribute to the improvement of the mechanical properties of the friction stir welded joints.

ACS Style

Yeong-Seok Lim; Sang-Hyuk Kim; Kwang-Jin Lee. Effect of Residual Stress on the Mechanical Properties of FSW Joints with SUS409L. Advances in Materials Science and Engineering 2018, 2018, 1 -8.

AMA Style

Yeong-Seok Lim, Sang-Hyuk Kim, Kwang-Jin Lee. Effect of Residual Stress on the Mechanical Properties of FSW Joints with SUS409L. Advances in Materials Science and Engineering. 2018; 2018 ():1-8.

Chicago/Turabian Style

Yeong-Seok Lim; Sang-Hyuk Kim; Kwang-Jin Lee. 2018. "Effect of Residual Stress on the Mechanical Properties of FSW Joints with SUS409L." Advances in Materials Science and Engineering 2018, no. : 1-8.

Research article
Published: 13 August 2017 in Advances in Mechanical Engineering
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Friction stir welding of Ti–6Al–4V alloy sheets was successfully performed with a tungsten carbide (WC) tool, and the effect of the tool rotational speed on the microstructure and mechanical properties of the joints was evaluated. The microstructure was investigated using field emission scanning electron microscopy, electron backscattered diffraction and X-ray diffraction measurements. Tensile, Charpy impact and Vickers hardness tests were performed to evaluate the joints’ mechanical properties. The process peak temperature of each welding condition was measured at the bottom of a specimen. Regardless of the welding conditions, the alpha (α) and alpha prime (α′) phases were detected in the stir zone, whereas the base metal was composed of alpha (α) and beta (β) phases. The tensile strength and hardness of the stir zone increased as the tool rotational speed increased. The impact absorption energy was found to be equal to that of the base metal. Moreover, a phase transformation from the β to the α′ phases occurred in the stir zone during friction stir welding and the evolution of the microstructure in the stir zone significantly affected the mechanical properties of the joints.

ACS Style

Young-Ju Ko; Kwang-Jin Lee; Kyeong-Ho Baik. Effect of tool rotational speed on mechanical properties and microstructure of friction stir welding joints within Ti–6Al–4V alloy sheets. Advances in Mechanical Engineering 2017, 9, 1 .

AMA Style

Young-Ju Ko, Kwang-Jin Lee, Kyeong-Ho Baik. Effect of tool rotational speed on mechanical properties and microstructure of friction stir welding joints within Ti–6Al–4V alloy sheets. Advances in Mechanical Engineering. 2017; 9 (8):1.

Chicago/Turabian Style

Young-Ju Ko; Kwang-Jin Lee; Kyeong-Ho Baik. 2017. "Effect of tool rotational speed on mechanical properties and microstructure of friction stir welding joints within Ti–6Al–4V alloy sheets." Advances in Mechanical Engineering 9, no. 8: 1.

Article
Published: 20 June 2017 in Journal of Materials Engineering and Performance
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Friction stir lap welding of dual phase 590 steel has been successfully performed within the A1 to A3 temperature range upon adjusting the process parameters. The microstructures and the texture have been characterized using scanning electron microscopy and electron back scattered diffraction analysis. The martensite volume fraction increases with an increasing travel speed from 100 to 300 mm/min for a constant tool rotational speed of 300 rpm. Under severe deformation and high strain rate during friction stir welding, the grain orientation 〈101〉 shifts toward the 〈111〉 and 〈001〉 directions compared to the base metal. The base metal shows γ fiber components, whereas the friction stir welded specimen shows strong brass with weak cube fibers.

ACS Style

Hrishikesh Das; Kwang-Jin Lee; Sung-Tae Hong. Study on Microtexture and Martensite Formation of Friction Stir Lap-welded DP 590 Steel within A1 to A3 Temperature Range. Journal of Materials Engineering and Performance 2017, 26, 3607 -3613.

AMA Style

Hrishikesh Das, Kwang-Jin Lee, Sung-Tae Hong. Study on Microtexture and Martensite Formation of Friction Stir Lap-welded DP 590 Steel within A1 to A3 Temperature Range. Journal of Materials Engineering and Performance. 2017; 26 (7):3607-3613.

Chicago/Turabian Style

Hrishikesh Das; Kwang-Jin Lee; Sung-Tae Hong. 2017. "Study on Microtexture and Martensite Formation of Friction Stir Lap-welded DP 590 Steel within A1 to A3 Temperature Range." Journal of Materials Engineering and Performance 26, no. 7: 3607-3613.

Journal article
Published: 09 March 2017 in International Journal of Precision Engineering and Manufacturing
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ACS Style

Ju-Ri Kim; Eun-Yeong Ahn; Hrishikesh Das; Yong-Ha Jeong; Sung-Tae Hong; Michael Miles; Kwang-Jin Lee. Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys. International Journal of Precision Engineering and Manufacturing 2017, 18, 445 -452.

AMA Style

Ju-Ri Kim, Eun-Yeong Ahn, Hrishikesh Das, Yong-Ha Jeong, Sung-Tae Hong, Michael Miles, Kwang-Jin Lee. Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys. International Journal of Precision Engineering and Manufacturing. 2017; 18 (3):445-452.

Chicago/Turabian Style

Ju-Ri Kim; Eun-Yeong Ahn; Hrishikesh Das; Yong-Ha Jeong; Sung-Tae Hong; Michael Miles; Kwang-Jin Lee. 2017. "Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys." International Journal of Precision Engineering and Manufacturing 18, no. 3: 445-452.

Journal article
Published: 04 August 2015 in International Journal of Precision Engineering and Manufacturing
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Strain-hardened aluminum-magnesium alloy (aluminum 5052-H112 alloy) plates are successfully friction stir processed. The thermal conductivity of the FSPed aluminum alloy is consistently measured to be higher than that of the base metal, even though the amount of grain boundaries significantly increases in the FSPed zone due to grain size refinement by FSP as observed by electron back-scatter diffraction (EBSD) analysis. In terms of thermal conductivity of the selected strain-hardened aluminum alloy, the result suggests that the effect of reduced dislocation by recrystallization, which is confirmed by X-ray diffraction analysis, surpasses the effect of increased grain boundaries due to grain size refinement. As the tool rotation speed increases, the thermal conductivity of the FSPed aluminum alloy increases even more, since the dislocation density in FSPed zone decreases further while the effect of grain size refinement is diminished by a slight grain growth.

ACS Style

Yong-Ha Jeong; Abu Mowazzem Hossain; Sung-Tae Hong; Kyung-Sik Han; Kwang-Jin Lee; Ju-Won Park; Heung Nam Han. Effects of friction stir processing on the thermal conductivity of a strain-hardened Al-Mg alloy. International Journal of Precision Engineering and Manufacturing 2015, 16, 1969 -1974.

AMA Style

Yong-Ha Jeong, Abu Mowazzem Hossain, Sung-Tae Hong, Kyung-Sik Han, Kwang-Jin Lee, Ju-Won Park, Heung Nam Han. Effects of friction stir processing on the thermal conductivity of a strain-hardened Al-Mg alloy. International Journal of Precision Engineering and Manufacturing. 2015; 16 (9):1969-1974.

Chicago/Turabian Style

Yong-Ha Jeong; Abu Mowazzem Hossain; Sung-Tae Hong; Kyung-Sik Han; Kwang-Jin Lee; Ju-Won Park; Heung Nam Han. 2015. "Effects of friction stir processing on the thermal conductivity of a strain-hardened Al-Mg alloy." International Journal of Precision Engineering and Manufacturing 16, no. 9: 1969-1974.

Journal article
Published: 01 April 2015 in Materials Science and Engineering: A
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ACS Style

Duck-Soo Kang; Kwang-Jin Lee; Eui-Pyo Kwon; Toshihiro Tsuchiyama; Setsuo Takaki. Variation of work hardening rate by oxygen contents in pure titanium alloy. Materials Science and Engineering: A 2015, 632, 120 -126.

AMA Style

Duck-Soo Kang, Kwang-Jin Lee, Eui-Pyo Kwon, Toshihiro Tsuchiyama, Setsuo Takaki. Variation of work hardening rate by oxygen contents in pure titanium alloy. Materials Science and Engineering: A. 2015; 632 ():120-126.

Chicago/Turabian Style

Duck-Soo Kang; Kwang-Jin Lee; Eui-Pyo Kwon; Toshihiro Tsuchiyama; Setsuo Takaki. 2015. "Variation of work hardening rate by oxygen contents in pure titanium alloy." Materials Science and Engineering: A 632, no. : 120-126.

Journal article
Published: 01 July 2014 in Transactions of Nonferrous Metals Society of China
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This study was performed to investigate microstructure of dissimilar friction stir welds manufactured with AA6061-T6 and AZ31 alloy sheets. Dissimilar butt joints were fabricated under the ‘off-set’ condition that tool plunge position shifted toward AZ31 from the interface between AA6061-T6 and AZ31. Optimized tool rotating speed and its traveling speed were selected through a lot of preliminary experiments. Electron back-scatter diffraction (EBSD) technique was applied to measure texture in the stir zone (SZ). Grain size distribution and misorientation angle distribution were also obtained. A remarkably fine-grained microstructure was observed in the SZ. Randomized or weaker plane orientations were formed in the SZ of AA6061-T6, while rotated basal plane orientations were concentrated in the SZ of AZ31. Average size of recrystallized grains was measured as just 2.5–4.5 μm. The fraction of high-angle boundary in the SZ of AA6061-T6 increased and that of low-angle boundary in the SZ of AZ31 decreased compared with the base metals.

ACS Style

Kwang-Jin Lee; Eui-Pyo Kwon. Microstructure of stir zone in dissimilar friction stir welds of AA6061-T6 and AZ31 alloy sheets. Transactions of Nonferrous Metals Society of China 2014, 24, 2374 -2379.

AMA Style

Kwang-Jin Lee, Eui-Pyo Kwon. Microstructure of stir zone in dissimilar friction stir welds of AA6061-T6 and AZ31 alloy sheets. Transactions of Nonferrous Metals Society of China. 2014; 24 (7):2374-2379.

Chicago/Turabian Style

Kwang-Jin Lee; Eui-Pyo Kwon. 2014. "Microstructure of stir zone in dissimilar friction stir welds of AA6061-T6 and AZ31 alloy sheets." Transactions of Nonferrous Metals Society of China 24, no. 7: 2374-2379.

Journal article
Published: 30 April 2014 in Journal of Welding and Joining
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ACS Style

Kwang-Jin Lee; Sang-Hyuk Kim; Eui-Pyo Kwon; Kyu-Song Son. Friction Stir Welding of 900MPa Grade TWIP Steel. Journal of Welding and Joining 2014, 32, 9 -13.

AMA Style

Kwang-Jin Lee, Sang-Hyuk Kim, Eui-Pyo Kwon, Kyu-Song Son. Friction Stir Welding of 900MPa Grade TWIP Steel. Journal of Welding and Joining. 2014; 32 (2):9-13.

Chicago/Turabian Style

Kwang-Jin Lee; Sang-Hyuk Kim; Eui-Pyo Kwon; Kyu-Song Son. 2014. "Friction Stir Welding of 900MPa Grade TWIP Steel." Journal of Welding and Joining 32, no. 2: 9-13.

Journal article
Published: 05 February 2014 in Korean Journal of Metals and Materials
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ACS Style

Jian Tian; Kee Do Woo; Kwang Jin Lee; Yuyong Chen. Effect of Step Quenching and Zr Addition on the Microstructure and Mechanical Properties of Al-Mg-Si Alloy. Korean Journal of Metals and Materials 2014, 52, 101 -111.

AMA Style

Jian Tian, Kee Do Woo, Kwang Jin Lee, Yuyong Chen. Effect of Step Quenching and Zr Addition on the Microstructure and Mechanical Properties of Al-Mg-Si Alloy. Korean Journal of Metals and Materials. 2014; 52 (2):101-111.

Chicago/Turabian Style

Jian Tian; Kee Do Woo; Kwang Jin Lee; Yuyong Chen. 2014. "Effect of Step Quenching and Zr Addition on the Microstructure and Mechanical Properties of Al-Mg-Si Alloy." Korean Journal of Metals and Materials 52, no. 2: 101-111.

Journal article
Published: 01 February 2013 in Defect and Diffusion Forum
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In this study, effects of Nd addition on mechanical properties and fracture behaviors of as-extruded Mg-5Al-3Ca based alloy were investigated by a tensile test at elevated temperatures. For all temperatures, addition of Nd elements resulted in further increase of strength both yield and ultimate strength compared to the Mg-5Al-3Ca alloy. At 150°C, the ductility in Nd-added alloys is lower than that of no-Nd addition alloy. However, at 250°C, the ductility in Nd-added alloys is improved for no-Nd addition alloy because of fine grain and suppression of grain growth by formation of thermally stable Al2Nd intermetallic compounds.

ACS Style

Hyeon Taek Son; Kwang Jin Lee; Yong Hwan Kim. Mechanical Properties and Fracture Behavior of Hot Extruded Mg-5Al-3Ca-xNd Alloys at Elevated Temperature. Defect and Diffusion Forum 2013, 334-335, 199 -202.

AMA Style

Hyeon Taek Son, Kwang Jin Lee, Yong Hwan Kim. Mechanical Properties and Fracture Behavior of Hot Extruded Mg-5Al-3Ca-xNd Alloys at Elevated Temperature. Defect and Diffusion Forum. 2013; 334-335 ():199-202.

Chicago/Turabian Style

Hyeon Taek Son; Kwang Jin Lee; Yong Hwan Kim. 2013. "Mechanical Properties and Fracture Behavior of Hot Extruded Mg-5Al-3Ca-xNd Alloys at Elevated Temperature." Defect and Diffusion Forum 334-335, no. : 199-202.

Journal article
Published: 01 January 2013 in Journal of Nanoscience and Nanotechnology
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An ultrafine grain (UFG) complex lamella aluminum alloy sheet was successfully fabricated by ARB process using AA1050 and AA6061. The lamella thickness of the alloy became thinner and elongated to the rolling direction with increasing the number of ARB cycles. By TEM observation, it is revealed that the aspect ratio of UFGs formed by ARB became smaller with increasing the number of ARB cycles. In addition, the effect of ARB process on the development of deformation texture at the quarter thickness of ARB-processed sheets was clarified. ARB process leaded to the formation of the rolling texture with shear texture and weak cube orientation. The subdivision of the grains to the rolling direction began to occur after 3 cycles of the ARB, resulting in formation of ultrafine grains with small aspect ratio. After 5 cycles, the ultrafine grained structure with the average grain diameter of 560 nm develops in almost whole regions of the sample.

ACS Style

Seong-Hee Lee; Jae-Yeol Jeon; Kwang-Jin Lee. Microstructure and texture of a nano-grained complex Al alloy fabricated by accumulative roll-bonding of dissimilar Al alloys. Journal of Nanoscience and Nanotechnology 2013, 13, 509 -512.

AMA Style

Seong-Hee Lee, Jae-Yeol Jeon, Kwang-Jin Lee. Microstructure and texture of a nano-grained complex Al alloy fabricated by accumulative roll-bonding of dissimilar Al alloys. Journal of Nanoscience and Nanotechnology. 2013; 13 (1):509-512.

Chicago/Turabian Style

Seong-Hee Lee; Jae-Yeol Jeon; Kwang-Jin Lee. 2013. "Microstructure and texture of a nano-grained complex Al alloy fabricated by accumulative roll-bonding of dissimilar Al alloys." Journal of Nanoscience and Nanotechnology 13, no. 1: 509-512.

Conference paper
Published: 04 September 2012 in ICAA13: 13th International Conference on Aluminum Alloys
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This chapter contains sections titled: Introduction Experimental Results & discussion Conclusions

ACS Style

Kwang-Jin Lee; Sang-Hyuk Kim; Hyeon-Taek Son; Kee-Do Woo. Microstructure and Mechanical Properties of Dissimilar Friction Stir Welds Using AA6061-T6 and AZ. ICAA13: 13th International Conference on Aluminum Alloys 2012, 643 -646.

AMA Style

Kwang-Jin Lee, Sang-Hyuk Kim, Hyeon-Taek Son, Kee-Do Woo. Microstructure and Mechanical Properties of Dissimilar Friction Stir Welds Using AA6061-T6 and AZ. ICAA13: 13th International Conference on Aluminum Alloys. 2012; ():643-646.

Chicago/Turabian Style

Kwang-Jin Lee; Sang-Hyuk Kim; Hyeon-Taek Son; Kee-Do Woo. 2012. "Microstructure and Mechanical Properties of Dissimilar Friction Stir Welds Using AA6061-T6 and AZ." ICAA13: 13th International Conference on Aluminum Alloys , no. : 643-646.

Journal article
Published: 27 April 2012 in Metals and Materials International
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The relationship between the texture and mechanical properties of 6xxx aluminum alloy sheets processed via cross rolling was investigated. The microstructures of the conventional rolled and cross rolled sheets after annealing were analyzed using optical micrographs (OM). The texture distribution across the thickness in the Al-Mg-Si-Cu alloy, conventional rolled sheets, and cross rolled sheets both before and after annealing was investigated via X-ray texture measurements. The texture was analyzed in three layers from the surface to the center of the sheet. The β-fiber texture of the conventional rolled sheet was typical of the texture obtained using aluminumoll ring. After annealing, the typical β-fiber orientations were changed to recrystallization textures: cube{001}〈100〉 and normal direction (ND)-rotated cubes. However, the texture of the cross rolled sheet was composed of an asymmetrical, rolling direction (RD)-rotated cubes. After annealing, the asymmetrical orientations in the cross rolled sheet were changed to a randomized texture. The average R-value of the annealed cross rolled sheets was higher than that of the conventional rolled sheets. The limit dome height (LDH) test results demonstrated that cross rolling is effective in improving the formability of the Al-Mg-Si-Cu alloy sheets.

ACS Style

Jae-Yeol Jeon; Hyeon-Taek Son; Kee-Do Woo; Kwang-Jin Lee. Texture and mechanical properties of Al-0.5Mg-1.0Si-0.5Cu alloy sheets manufactured via a cross rolling method. Metals and Materials International 2012, 18, 295 -301.

AMA Style

Jae-Yeol Jeon, Hyeon-Taek Son, Kee-Do Woo, Kwang-Jin Lee. Texture and mechanical properties of Al-0.5Mg-1.0Si-0.5Cu alloy sheets manufactured via a cross rolling method. Metals and Materials International. 2012; 18 (2):295-301.

Chicago/Turabian Style

Jae-Yeol Jeon; Hyeon-Taek Son; Kee-Do Woo; Kwang-Jin Lee. 2012. "Texture and mechanical properties of Al-0.5Mg-1.0Si-0.5Cu alloy sheets manufactured via a cross rolling method." Metals and Materials International 18, no. 2: 295-301.

Journal article
Published: 31 August 2011 in Metals and Materials International
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This study investigates the effect of microstructural changes induced by hot rolling on the formation of the texture in high-strength aluminum alloy sheets used in automotive applications. Fully (S2) and partially (S1) re-crystallized samples were fabricated by controlling the final hot-rolling temperature. Optical microscopy (OM) was used to observe the microstructure of the transverse direction (TD)-plane of the hot-rolled strips, and the electron back-scattered diffraction (EBSD) technique was used to evaluate the texture of the normal direction (ND)-plane of the finished sheets that were subjected to hot rolling, followed by cold rolling and a solid-solution heat treatment (SSHT). The grains in S1 showed a low-angle grain boundary, and the concentrations of Cube {001}〈100〉 and Goss {011}〈100〉 orientations were detected at different sheet thicknesses. In contrast, a randomized texture was observed in S2. On the basis of the above results, this paper discusses how the microstructure and texture achieved after hot rolling can influence the final microstructure, texture and surface roughening behavior.

ACS Style

Kwang-Jin Lee; Kee-Do Woo. Effect of the hot-rolling microstructure on texture and surface roughening of Al-Mg-Si series aluminum alloy sheets. Metals and Materials International 2011, 17, 689 -695.

AMA Style

Kwang-Jin Lee, Kee-Do Woo. Effect of the hot-rolling microstructure on texture and surface roughening of Al-Mg-Si series aluminum alloy sheets. Metals and Materials International. 2011; 17 (4):689-695.

Chicago/Turabian Style

Kwang-Jin Lee; Kee-Do Woo. 2011. "Effect of the hot-rolling microstructure on texture and surface roughening of Al-Mg-Si series aluminum alloy sheets." Metals and Materials International 17, no. 4: 689-695.