Abstract
The effect of carbon addition on the cast and rolled microstructures of CoCrFeMnNi high entropy alloys were studied. Both as-cast CoCrFeMnNi and CoCrFeMnNiC0.1 alloys have a dendritic microstructure. Small carbide particles were observed at the inter-dendritic region in the as-cast CoCrFeMnNiC0.1 and elongated-grained structure with aligned carbides were developed at..... More

Abstract
High entropy alloys (HEAs) are a relatively new class of metallic materials. HEAs lead to high mixing entropy and the formation of a simple solid solution rather than intermediate phases. This might be explained by the fact that the configurational entropy outweighs the enthalpy of formation of intermetallic compounds. Meanwhile,..... More

Abstract
This study investigated hydrogen induced cracking (HIC) of X70 steel, used for gas pipeline material, with a bainitic microstructure. The effect of hydrogen on the steel was investigated by tensiletesting in a high pressure hydrogen atmosphere, using OM, SEM and TEM analyses. The mechanisms of hydrogen-related cracking were represented as..... More

Abstract
Since strength and ductility have a trade-off relationship in Al alloys, controlling these properties using heat treatments requires careful attention to the dissolution and evolution of the reinforcing phases. In this study, the effects of solution and aging treatments on the microstructure and mechanical properties of Al-5.2Si-3.4Cu-0.28Mg alloy were investigated...... More

Abstract
This study investigated the microstructure and the ambient-elevated temperature compression and elevated temperature creep properties of Fe-14Cr ferritic ODS steel manufactured by mechanical alloying (high energy ball milling) and hot extrusion processes. Initial microstructural observation of the as-extruded material identified elongated grains in the direction of extrusion; however, some recrystallization..... More

Abstract
The effects of cooling after solution heat treatment on the microstructure and mechanical properties of light-weight steels were investigated using Fe^-30Mn^-xAl^-0.9C alloys containing 9.0–12.8 wt% Al. Lab^-scale specimens (thickness: 10 mm) of the alloys were cooled by different cooling rates from -337 to -0.053 ℃/s using water, air, and furnace..... More

Abstract
The effect of current densities on the electromigration (EM) failure mechanism of flip chip Cu/Ni/Sn-Ag/Cu solder bumps was investigated under stressing conditions at current densities ranging from 5.0~6.9 × 10³ A/cm² at 150 ℃. The EM failure times at 5.0 × 10³ A/cm² were around 11 times longer than at..... More

Abstract
A polycrystalline diamond compact (PDC) is a two-stage sintered body manufactured by placing diamond powders on a WC-Co hard material and then applying the high pressure high temperature (HPHT) sintering process. This study investigated the microstructure and wear properties of the PDC depending on initial diamond particle size. Three different..... More

Abstract
In this study, the effects of microstructural variations in heavy-section reactor pressure vessel (RPV) steels on tensile and Charpy impact properties were investigated. Two PRV blocks, OPR1000 and APR1400 (ORV, ARV) were taken from the archive materials used in Korea standard nuclear power plants. Test specimens were sampled from five..... More

Abstract
In this study, we made large-scale ingots of CoCrFeMnNi high entropy alloy by vacuum induction melting. The as-cast CoCrFeMnNi high entropy alloy contained a high proportion of columnar structures with a few equiaxed grains, and showed single phase fcc solid solutions without macro segregation and low interstitial levels. The tensile..... More

Abstract
Age hardening and re-crystallization softening of a type of high entropy alloy, CoCrFeMnNi, was performed to investigate the relationship between microstructure and the property of mechanical hardness. Equiatomic CoCrFeMnNi was produced by casting followed by homogenizing, cold rolling and post heat treatments. TEM analysis revealed that the microstructure of the..... More

Abstract
Abstract: High-entropy alloys (HEAs), which are defined as a single phase crystalline solid solution with the composition of each constituent element in the range of 5-35 at%, have been the subject of intensive study in the last decade. Most of the HEA research is focused on alloy design, microstructural characterization,..... More

Abstract
Austenitic stainless steels have excellent mechanical property and corrosion resistance, and are for these reasons used in demanding applications such as power plant, nuclear reactor and off-shore plant. Especially, austenitic stainless steel 304 (STS304) is mainly used as a pipe material in nuclear power plants. Submerged arc welding (SAW) is..... More

Abstract
In this paper, the soft magnetic properties and compaction density of Fe-Si-B-Nb-Cu nanocrystalline powder cores, mixed with two kinds of permalloy powders (Ni₇₀Fe₃₀ or Ni₅₀Fe₅₀), have been closely studied. Permalloy powders having an average diameter of 4μm were added in the range of 5 to 15 wt%, and the powder..... More

Abstract
The wetting behavior of liquids on solid surfaces is important in the study of surfaces and interfaces. In this study, the wetting behavior of deionized (DI) water and hexadecane on fluorinated and micro-patterned polymer surfaces was investigated. The sample surfaces were processed by spray coating and thermal imprinting, respectively. The..... More

Abstract
A new Ni based superalloy with high fatigue resistance and fine grain was considered as a material for high-pressure buckets in fossil fuel power plants. Since such buckets are usually exposed to extreme operating conditions, low cycle fatigue tests were conducted to understand the microstructure evolution of the material during..... More

Abstract
The effects of oxygen content on the β to α phase transformation of the Ti-5Al-2.5Fe alloy during continuous cooling were investigated by varying the oxygen content between 0.08 – 0.41 wt%. Dilatometer tests were performed at cooling rates of 0.05 – 100 ℃/s combined with microstructure observation to examine phase..... More

Abstract
In this paper, the influence of mixed-type (impressed-current and sacrificial-anode) cathodic protection on an underwater electromagnetic field was investigated using the boundary element method. The current applied for cathodic protection was reduced by installing sacrificial anodes in the stern region. Also, the potential difference produced by the propeller in the..... More

Abstract
To realize focused design near-field conduction noise absorbers for sub-GHz frequencies, this study proposes screen-printed conductive grid films. The films’ advantages include large-scale production and easy control of electrical properties. A conductive grid film with a resistance value of approximately 70 Ω was screen printed on polyimide film substrate and..... More

Abstract
The delayed cracking behavior of deep-drawn lean duplex stainless steel (LDSS) was investigated, and compared with that of conventional metastable austenitic stainless steels (MASS). Hydrogen charging was performed by electrochemical method, and the hydrogen-charged specimens were subjected to the slow-strain-rate test. Fractures occurred along the phase boundaries in the LDSS,..... More

Abstract
To study the effect of Al and Zr contents on the microstructural changes and tensile properties of Ni-Al-Bronze alloy, seven specimens were cast with different Al and Zr contents. The microstructure observation revealed that all specimens were composed of β’ and κ phases in a α matrix. With increasing Al..... More

Abstract
A new Ni based superalloy is considered as bucket material because of high fatigue resistance with fine grain. However a bucket is usually exposed to high temperature for a long time, so creep rupture tests were conducted to understand the microstructure evolution during creep deformation under various stresses at temperatures..... More

Abstract
The hot deformation behavior of as-cast and homogenized Fe-22Cr-9.5Mn-3.3Ni stainless steel was investigated over a temperature range between 600~1,250 ℃. The deformability of the as-cast Fe-22Cr-9.5Mn-3.3Ni steel decreased with increasing temperature up to 850 ℃, and then increased at temperatures between 900 and 1200 ℃ caused by dynamic recrystallization at..... More

Abstract
A feasibility study on microstructure design has been carried out to improve creep rupture life in alumina-forming austenitic (AFA) Fe-14Cr-20Ni-2.3Al stainless steel with and without 2 wt% W addition. After creep tests under 780 °C/80 MPa conditions, it was observed that internal cracks initiated primarily from grain boundaries in the..... More

Abstract
In this study, neodymium (Nd) nuclides in LiCl-KCl eutectic salts were captured and solidified using a synthetic inorganic composite (Li₂O-SiO₂-Al₂O₃-B₂O₃), a process that allows the selective capture of Nd and fabrication of a composite with Nd captured from waste, without additional additives or mixing. The Nd nuclides in the LiCl-KCl..... More

Abstract
The square loop (SL) is the typical pattern of a frequency selective surface (FSS) with high inductance (L) and capacitance (C). In this study, modified patterns including split square loop FSS (SSL-FSS) and I-type FSS (I-FSS) are proposed, and their L and C values were estimated using the equivalent circuit..... More

Abstract
The influence of ultrasonic melt treatment (UST) combined with a change in cooling rates on the microstructure and elevated temperature mechanical properties of a hypereutectic Al-18Si-4Cu-3Ni piston alloy was investigated. Microstructural observation confirmed that UST effectively refined the sizes of primary Si and intermetallic compounds (e.g. ε-Al₃Ni) while promoting their..... More

Abstract
An as-received EMC/S (electromagnetic casting and stirring)-processed Al-12Si based alloy billet was homogenized to examine its microstructure and high temperature plastic deformation behavior, using compressive tests over the temperature range from 623 to 743 K and a strain rate range from 1.0×10^-3 to 1.0×10⁰s^-1. The results were compared with samples..... More

Abstract
The resistance of hydrogen induced cracking (HIC) was investigated with different microstructures of API X70MS steel. Ferrite/acicular ferrite (F/AF), deformed ferrite/acicular ferrite, ferrite/bainite (F/B) and single acicular ferrite (AF) were obtained by thermo-mechanical controlled process (TMCP) with changing rolling and cooling conditions. HIC resistance was found to be affected by..... More