15 Result(s)
within
Article
Yoon-Uk Heo
Materials Science
-
Article
Microscopic Study on the Blister Formation Mechanism in Electrogalvanized Steel
The blister formation mechanism in electrogalvanized steel was studied by analyzing the blister’s internal structure. Electrochemical hydrogen charging was employed to absorb hydrogen into the steel plate and ...
-
Article
Open AccessEPMA quantification on the chemical composition of retained austenite in a Fe-Mn-Si-C-based multi-phase steel
An electron probe X-ray microanalyzer (EPMA) is an essential tool for studying chemical composition distribution in the microstructure. Quantifying chemical composition using standard specimens is commonly use...
-
Article
Kinetic Model to Investigate the Effect of Cooling Rate on δ-Ferrite Behavior and Its Application in Continuous Casting of AISI 304 Stainless Steel
The prediction of M-shaped δ-ferrite content along the thickness direction of continuously cast 304 austenitic stainless steel slab was performed using a diffusion-controlled phase transformation module of The...
-
Article
Open AccessComparative study on the specimen thickness measurement using EELS and CBED methods
Two thickness measurement methods using an electron energy loss spectroscopy (EELS) and 10a convergent beam electron diffraction (CBED) were compared in an Fe-18Mn-0.7C alloy. The thin foil specimen was firstl...
-
Article
Determination of Yield Stress in a Duplex Steel with α + γ Lamellar Structure
Yield stress σy is evaluated in a duplex steel with α + γ lamellar structure by calculating the stress for the propagation of pile-up dislocations in one phase into another phase. Effective grain size of a lamell...
-
Article
Tempering Behavior of TiC-Reinforced SKD11 Steel Matrix Composite
TiC-reinforced SKD11 steel matrix composite, fabricated by a pressure infiltration casting, undergoes monotonic decrease in hardness as tempering temperature increases. Element map**s by TEM–EDS and thermody...
-
Article
Deformation Behavior in Medium Mn Steel of Nanometer-Sized α′ + γ Lamellar Structure
Yielding and work-hardening phenomena in an Fe-10.62Mn-2.84Al-0.17C-0.5Mo steel, which is composed of nanometer-sized lamellae of α′ and γ, are described on the basis of the Hall–Petch relations. Unlike the gener...
-
Article
Influence of the Initial Microstructure on the Reverse Transformation Kinetics and Microstructural Evolution in Transformation-Induced Plasticity–Assisted Steel
The reverse transformation behavior upon heating to intercritical temperature was studied in Fe-0.21C-2.2Mn-1.5Si (wt pct) alloy with three initial microstructures. One is the cold-rolled (CR) structure and t...
-
Article
Enhanced low-cycle fatigue life by pre-straining in an Fe-17Mn-0.8C twinning induced plasticity steel
Enhancement of low-cycle fatigue (LCF) life was achieved by imposing pre-straining in an Fe-17Mn-0.8C twinning induced plasticity steel. Two different straining methods (uni-axial tension and drawing) were uti...
-
Article
Controlled Ag-driven superior rate-capability of Li4Ti5O12 anodes for lithium rechargeable batteries
The morphology and electronic structure of a Li4Ti5O12 anode are known to determine its electrical and electrochemical properties in lithium rechargeable batteries. Ag-Li4Ti5O12 nanofibers have been rationally de...
-
Article
Kinetic transition during the growth of proeutectoid ferrite in Fe-C-Mn-Si quaternary steel
The kinetics of ferrite growth in Fe-0.1C-1.5Mn-0.94Si (mass pct) quaternary steel is investigated through the characterization of isothermal growth behavior, the thermodynamic prediction of kinetic boundary a...
-
Article
Precipitates and Grain Boundary Strength of an Fe-Mn-Ni Alloy
The effect of grain boundary (GB) precipitates on the GB strength of an age-hardened Fe-7.8Mn-8.2Ni alloy was investigated. Premature intergranular fracture was observed after age hardening due to the precipit...
-
Article
Influence of Silicon in Low Density Fe-C-Mn-Al Steel
The influence of silicon on the microstructure of a Fe-Mn-Al-C ferritic low-density steel is investigated. The formation of κ-carbide, which is known to be detrimental to ductility, can be suppressed by decrea...
-
Article
Open AccessMicroscopic role of carbon on MgB2 wire for critical current density comparable to NbTi
Increasing dissipation-free supercurrent has been the primary issue for practical application of superconducting wires. For magnesium diboride, MgB2, carbon is known to be the most effective dopant to enhance hig...
-
Article
Initial transient structure and chemistry of intergranular glassy films in ferric-oxide doped strontium titanate ceramics
Intergranular glassy films (IGFs) often play a key role in the formation of microstructure and the resultant properties in titanate-based materials. In this article, a systematic study of IGF structure and che...
