75 Result(s)
within
Changhee Lee
Characterization and Evaluation of Materials
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Article
Heat-Affected Zone Characteristics with Post-Weld Heat Treatments in Austenitic Fe–Mn–Al–C Lightweight Steels
This study investigates the relationship between the mechanical characteristics and microstructural transitions in heat-affected zone (HAZ) of various austenitic Fe–Mn–Al–C lightweight steels. The analysis was...
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Article
Correlation Between Constituent Phase and Weld Metal Properties in Ni-Reduced Duplex Stainless Steel
The intrinsic properties of austenite and ferrite on the mechanical properties and corrosion resistance of the duplex stainless steel weld metals was studied by substituting Ni with Mn, N, and Mn + N. The prop...
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Article
Kinetics Study on Low-Temperature Tempering of Martensitic Phase in Medium Mn Steel Weldment During Paint-Baking Heat Treatment
The kinetics of low-temperature tempering in a dissimilar resistance spot weldment between medium Mn transformation-induced plasticity (MT) steel and dual-phase (DP) steel were investigated to interpret the ch...
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Article
Effect of Surface Smoothness on the Structure of Scale and Formation of Surface Cracks in TiAl Alloys under Heat Treatment
The methods of optical and electron microscopy are used to study the relation between the processes of scale formation and propagation of surface cracks in TiAl alloys under heat treatment. It is shown that cr...
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Article
Surface Metallization and Ceramic Deposition on Thermoplastic-Polymer and Thermosetting-Polymer Composite Via Atmospheric Plasma Spraying
A spray coating technique is an excellent method for surface metallization and ceramic deposition to widen the application fields of irreplaceable engineering polymers. In this study, Al metallization and Al2O3 d...
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Article
Fusion Weldabilities of Advanced High Manganese Steels: A Review
A large amount of manganese has been added to next-generation advanced high strength steels for automotive applications. The increased manganese content changes the microstructural and mechanical characteristi...
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Article
Shock Absorption Effect on Particle Fragmentation and Microstructural Features of Vacuum-Kinetic-Sprayed Al2O3 Film on Polycarbonate Substrate
As the demand for flexible devices has increased, polymers have become very promising materials for these applications because they have excellent flexibility, lightweight, and low cost. Vacuum kinetic sprayin...
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Article
Impact Behavior for Successful Particle–Particle Bonding in Vacuum Kinetic Spraying
This study investigated the impact behavior of ceramic particles in vacuum kinetic spray (VKS), also known as aerosol deposition method, for successful coating build-up using both experimental methods and nume...
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Article
Reactivity Enhancement and Fabrication of Al-MoO3 Thermite Coating Using Ball Milling for Kinetic Spraying
Thermite materials, which are a pyrotechnic composition of metal and metal oxide, can create bursts of heat and high temperature thanks to an exothermic reduction–oxidation reaction. Fabrication methods of bul...
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Article
Microstructural and Inclusion Characteristics of C–Mn Steel Welds at a Minimal Level of Titanium
To better determine the lower limit of titanium content for the formation of acicular ferrite, C–Mn steel welds varying the titanium concentration at a minimal level from nearly zero to about 30 ppm have been ...
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Article
Correlation of Plasma Erosion Resistance and the Microstructure of YF3 Coatings Prepared by Vacuum Kinetic Spray
To decrease the generation of contamination particles during semiconductor manufacturing processes, a plasma-erosion-resistant coating that can prevent particle dropout on the surface of the wafer etching cham...
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Article
Tribological and Microstructural Properties of Carbon Steel Coatings Fabricated by Wire Arc Spray
Thermal spray is a widely used process employed for the reduction of engine weight by replacing heavy cast iron liners inserted in cylinder bores. In particular, twin wire arc spray (TWAS) is one of the most p...
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Article
Computational Research on Factors Affecting Particle Velocity in a Vacuum Kinetic Spray Process
In vacuum kinetic spraying (VKS) systems, also called aerosol deposition, the particle velocity is crucial because kinetic energy determines successful deposition. However, various factors simultaneously affec...
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Article
Roles of (Fe, Mn)3Al Precipitates and MBIP on the Hot Ductility Behavior of Fe–30Mn–9Al–0.9C Lightweight Steels
In the automotive industry, lightweight steel has received much attention because steel comprises a significant portion of a vehicle’s total weight. Fe–Mn–Al–C steel is a representative lightweight steel due t...
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Article
Formation of Secondary Phases and Their Effect on the Mechanical Properties of Joints Formed by TLP Bonding Using Fe–B–Si Insert Metal in Duplex Stainless Steel
We studied the effects of secondary phases on the mechanical properties of joints formed by transient liquid-phase bonding in nitrogen-containing duplex stainless steel UNS S32750. Transient liquid-phase bondi...
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Article
Characterization of Mechanical and Metallurgical Notch Effects of DP980 Steel Weld Joints in Fatigue Performance
This work investigates the use of 980 MPa grade dual-phase (DP) steel joints with pulsed current gas metal arc welding (P-GMAW) for reliable weld performance by comparing actual welded joints with thermo-mecha...
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Article
Performance Comparison of Double-Layer Liner for Shaped Charge Fabricated Using Kinetic Spray
Shaped charge (SC) ammunition is a weapon designed to penetrate armor. The functions of the liner, which is a core component of the SC, are penetration and explosion. Because of the increasing necessity for th...
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Article
Significance of Polymeric Nanowire-Network Structures for Stable and Efficient Organic Solar Cells
Evolution of favourable nanomorphology which can withstand external stimuli is a critical issue for efficient and stable organic solar cells. Here, we demonstrate a novel strategy for the stabilization of nano...
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Article
Roles of Particle Size Distribution in Bimodal Feedstocks on the Deposition Behavior and Film Properties in Vacuum Kinetic Spraying
Vacuum kinetic spray (VKS), also called aerosol deposition method, is a spray process that makes it possible to fabricate dense ceramic films at room temperature. Although the deposition rate of VKS is better...
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Article
Correlation Between Microstructure and Low-Temperature Impact Toughness of Simulated Reheated Zones in the Multi-pass Weld Metal of High-Strength Steel
A large fraction of reheated weld metal is formed during multi-pass welding, which significantly affects the mechanical properties (especially toughness) of welded structures. In this study, the low-temperatur...
