A5050526653- Advanced Welding Techniques Analysis
- Welding Techniques and Residual Stresses
- High-Velocity Impact and Material Behavior
- Aluminum Alloy Microstructure Properties
- Aluminum Alloys Composites Properties
- Microstructure and mechanical properties
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Metal Forming Simulation Techniques
- Fluid Dynamics Simulations and Interactions
- Metal and Thin Film Mechanics
- Semiconductor materials and interfaces
- Tribology and Lubrication Engineering
- Electromagnetic Launch and Propulsion Technology
- Electronic Packaging and Soldering Technologies
- Numerical methods in engineering
- Advanced Materials Characterization Techniques
- Mechanical Behavior of Composites
- Metal Alloys Wear and Properties
- Copper-based nanomaterials and applications
- Engineering Applied Research
- Metallic Glasses and Amorphous Alloys
- Electromagnetic Effects on Materials
- Fluid Dynamics and Heat Transfer
Incheon National University
2021-2024
The Ohio State University
2017-2020
Hyundai Motors (South Korea)
2019-2020
Numerical simulations of high-velocity impact welding are extremely challenging due to the coupled physics and highly dynamic nature process. Thus, conventional mesh-based numerical methodologies not able accurately model process owing excessive mesh distortion close interface two welded materials. A simulation platform was developed using smoothed particle hydrodynamics, implemented in a parallel architecture on supercomputer. Then, were compared experimental tests conducted by vaporizing...
A method for in situ Al 2 O 3 incorporation into a Cu ZnSn(S,Se) 4 (CZTSSe) absorber and its effect on solar cell performance is reported. ‐incorporated CZTSSe films can be prepared by spraying precursor solution containing metal salt dissolved together with Cu, Zn, Sn salts thiourea. X‐ray photoemission spectroscopy (XPS) field‐emission transmission electron microscopy (FESEM) reveal the existence of an phase film. diffraction (XRD) Raman indicate that (Al: 0%–2%) does not have noticeable...
Impact welding is a material processing technology that enables metallurgical bonding in the solid state using high-speed oblique collision. In this study, effects of thickness flier and collision angle on weld interface morphology were investigated through vaporizing foil actuator (VFAW) AA1100-O to AISI 1018 Steel. The interfaces at various controlled conditions show wavelength increasing with angle. sheets ranged from 0.127 1.016 mm. velocity fliers was directly measured by situ photon...
Abstract Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells have resource distribution and economic advantages. The main cause of their low efficiency is carrier loss resulting from recombination photo‐generated electron hole. To overcome this, it important to understand electron‐hole behavior characteristics. determine the separation characteristics, we measured surface potential local current in terms absorber depth. elemental variation intragrains (IGs) at grain boundaries (GBs) caused a band edge...
Abstract Understanding the defect characteristics that occur near space‐charge regions (SCRs) of kesterite (CZTSSe) solar cells is important because recombination loss at CZTSSe/CdS interface considered main cause their low efficiency. CZTSSe surfaces with different elemental compositions were formed without polishing (C00) and for 20 s (C20) 60 (C60). For C60, a specific region SCR was excessively Cu‐rich Zn‐poor compared to C00 C20. Various charged defects where variation large. As deep...
This study addresses issues relevant to resistance spot welding of AA5xxx and AA6xxx dissimilar aluminium alloys. Welding parameters are optimised provide the maximum lap-shear strength largest nugget size. As mechanical properties weld affected by characteristics heat-affected zone as well fusion zone, microscopic analysis was performed address microstructure performance. The asymmetrical morphology heterogeneous due distinctive physical strengthening mechanisms welded materials. current...
This study presents information on the behavior of paint baking (PB) after resistance spot welding 5- and 6xxx series aluminum alloys. The weld parameters are optimized, specimens baked three times for 20 min at 180 °C to simulate heat treatments required baking. mechanical properties samples were characterized by using lap shear test, micro/nanoindentation hardness, fatigue test. As affected characteristics heat-affected zone those fusion zone, microstructure cross-sections was also...
Resistance Element Welding (REW) is a novel processing technology developed to join dissimilar materials such as aluminum and steel. It uses an auxiliary steel rivet (element) inserted into sheet that forms resistance spot weld with the sheet, work piece mechanically joined by interlocking rivet. The versatility agility of REW advantageous, especially in automotive industry. However, head often extends out externally over piece, misalignment electrode can be problematic since inserting are...
Demands for weight reduction in automobiles have been constantly increasing due to its environmental impact, leading increased interests light metals such as aluminum and magnesium. However, most structural applications that require large energy absorption, implementation of high strength steel is still a pervasive solution.When the having martensite fraction (DP 980) joined by resistance spot welding, softening zone generated welds, welds. In addition, steels generally contain amount carbon...
Characteristic features of impact welding were investigated in a simple model system colliding copper single crystals. Large grained sheets used to approximate crystal impact. Optical microscopy and electron backscatter diffraction (EBSD) analyses showed multiple the weld interface, which include deformation twinning, adiabatic shear banding, localized melting, dynamic recrystallization. To support microstructural findings, numerical simulation based on smoothed particle hydrodynamics method...