By means of dynamic plastic deformation (DPD) followed by thermal annealing, a mixed structure of micro-sized austenite grains embedded with nano-scale twin bundles (of about 20% in volume) has been synthesized in a 316L stainless steel (SS). Such a 316L SS sample exhibits a tensile strength as high as 1001 MPa and an elongation-to-failure of about 23%. The much elevated strength originates from the presence of a considerable number of strengthening nano-twin bundles, while the ductility from the recrystallized grains. The superior strength-ductility combination achieved in the nano-twins-strengthened austenite steel demonstrates a novel approach for optimizing the mechanical properties in engineering materials.

Interest in solid oxide fuel cells (SOFC) stems from their higher efficiencies and lower levels of emitted pollutants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i:e:, to maintain high electrical conductivity, good stability in both reducing and oxidizing atmospheres, and close coefficient of thermal expansion (CTE) match and good compatibility with other SOFC ceramic components. The paper reviewed the interconnect materials, and coatings for metallic interconnect materials.

A nickel base single crystal (SC) superalloy was directionally solidified using liquid metal cooling (LMC) process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from 3 to 12 mm/min. However, higher withdrawal rate of 15 mm/min induced the formation of stray grains. Size and volume fraction of the eutectics were found to decrease with the increasing in withdrawal rate. After solution heat treatment at 1250°C, un-dissolved eutectic was observed in specimens. High temperature creep rupture life was observed to be very sensitive to the fraction of these remaining eutectics. Creep rupture tests at 1000°C/235 MPa showed that refined microstructure and low fraction of the remaining eutectic lead to significant improvement of the rupture life.

The transmission electron microscopy was employed to investigate the microstructure of infrared brazed high-strength Ti alloy using the Ti-15Cu-15Ni filler metal. Coarse primary Ti₂Ni and transformed β-Ti are observed in the 300 s brazed specimen. Blocky Ti₂Ni and eutectoid Ti₂Cu intermetallics are disappeared from the joint with increasing the brazing time to 1800 s. Both acicular α-Ti and retained β-Ti dominate the entire brazed joint.

Thermodynamic assessment of Ti-Co-Cu ternary system has been carried out by combining first-principle calculation and CALPHAD method. Firstly, formation enthalpies of stable and hypothesized compounds were calculated by first-principles method. Then, based on reported experimental information, a thermodynamic description of the Ti-Co-Cu ternary system was performed. Solution phases were treated as substitutional solutions of which excess Gibbs energies were formulated by Redlich-Kister polynomial, and the intermediate phases were described with sublattice models. All measured isothermal sections were reasonably reproduced. In addition, liquidus projection of this ternary system was further calculated, which may be useful for relevant materials processing.

It is known that fiber metal laminates (FML) as one of hybrid materials with thin metal sheets and fiber/epoxy layers have the characteristics of the excellent damage tolerance, fatigue and impact properties with a relatively low density. Therefore, the mechanical components using FML can contribute the enhanced safety level of the sound construction toward the whole body. In this study, the impact performance of carbon reinforced aluminum laminates (CARAL) is investigated by experiments and numerical simulations. Drop weight tests are carried out with the weight of 4.7 kg at the speed of 1 and 2 m/s, respectively. Dynamic non-linear transient analyses are also accomplished using a finite element analysis software, ABAQUS. The experiment results and numerical results are compared with impact load-time histories. Also, energy-time histories are applied to investigate the impact performance of CARAL.

SiO₂ coated α-Fe₂O₃ nanocomposite powder has been successfully synthesized by chemical vapor condensation process and its feasibility on hyperthermic application was investigated in this study. The power loss of SiO₂ coated α-Fe₂O₃ nanocomposite powder which means the magnetic heating effect under alternative magnetic field was much higher than the single phase α-Fe₂O₃ nano powder due to the very fine size under 20 nm and well dispersion in biologically compatible SiO₂ matrix. The superparamagnetism and hyperthermic property of SiO₂ coated α-Fe₂O₃ nanocomposite powder were discussed in terms of microstructural development in this study.

The mechanical properties of nano-scale Cu/FeS composite were simulated by molecular dynamics (MD) simulation in this paper. Through the analysis on the stress-strain curves, the results of MD simulation were in good agreement with mechanisms of macroscopic deformation. When the size of particles was smaller than a certain value, the relationship between yield strength and size, which was different from the large size crystals abided by the contrary Hall-Petch relationship. Based on the discussion of nano-scale Cu/FeS composite, some interesting conclusions were obtained. For example, the "S" type curves were discovered in stress-strain curves and the anisotropy of FeS was very evident when the exposures of reinforcing phase (FeS) were different and so on. The basic theories and calculations of the composite that contains nano-scale particles were discussed. At the same time, a new modeling building method of composites, which was close to actual experiences, were considered in this paper.

In this paper, a quaternary system of Mn_0.43Ni_0.9CuFe_0.67O₄ NTC thermistor ceramics prepared by solid/solid reaction were sintered by microwave and conventional method, respectively. In order to characterize the sinterability of the samples, the densification parameter, porosity and grain size distribution of the bulk were determined. The crystal structure, phase compositions, morphology and impedance of the samples were analyzed with XRD, SEM, EDS and impedance analysis. The experiment results confirmed that the sinterability and electrical properties of ceramics are homogenously improved by microwave sintering.

The effects of B₂O₃ addition, as a sintering agent, on the sintering behavior, microstructure and dielectric properties of CaMgSi₂O₆ ceramic have been investigated. The CaO-MgO-B₂O₃-SiO₂ glassy phase came forth by adding B₂O₃ into CaO-MgO-SiO₂ ceramic powders, and it was advantageous to lower the synthesis temperature of CaMgSi₂O₆ crystalline phase. Moreover, the emergence of CaO-MgO-B₂O₃-SiO₂ glass phase could effectively lower the sintering temperature of CaMgSi₂O₆ ceramic and promote the CaMgSi₂O₆ grains growing. With 6 wt pct B₂O₃ addition, the densification temperature of CaMgSi₂O₆ ceramic could be effectively reduced from 1300 to 1100°C, and the dielectric constant (ε_r) and dielectric loss (tanδ) were: ε_r=7.61 and tanδ=7.4×10^-4 (1 MHz).

The effects of an applied magnetic field on the corrosion process of beryllium copper in NaCl solution have been investigated by electrochemical measurements, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that a horizontal magnetic field with 0.4 T barely shifted the open circuit potentials (E_corr) of beryllium copper in NaCl solution with different concentrations. However, the horizontal magnetic field increased the limiting current density of beryllium copper in NaCl solution with low concentration, while decreased the limiting current density of beryllium copper in NaCl solution with high concentration. It was found that magnetic field accelerated the diffusion of CuCl^2- away from the electrode surface and delayed the formation of Cu₂O. The results of SEM and EDS showed that the influence of magnetic
field over the elements distribution of the corrosion products differed from the di®erent concentration of the immersion solution.

The objective of the this study is to investigate the effects of cutting parameters on thermal characteristics, including practical cutting regions, the formation of the kerfwidth and the heat transfer phenomenon, in the cutting of Inconel 718 super-alloy sheets using a CW Nd:YAG laser. From the results of the experiments, the influence of process parameters on both the practical cutting region and the kerfwidth has been examined. In addition, it has been shown that the kerfwidth of the specimen lies in the range of 0.53-0.61 mm. In order to examine characteristics of the heat transfer during the laser cutting process, a three-dimensional quasi-steady heat transfer analysis has been performed using the commercial code SYSWELD V9.0. From the results of the analysis, the in°uence of cutting parameters on the temperature distribution in the vicinity of the cut section
has been quantitatively evaluated. Based on these results, optimal cutting conditions have been estimated.

In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance in ordinary condition, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in usual air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below 130°C in air was 10-40 times higher than that of the normally passivated particles.

Atomic layer deposition (ALD) has become an essential deposition method for forming nanometer scale thin films in the microelectronics industry, and its applications have been extended to multi-component thin films, as well as to single metal oxide films. In order to investigate the development of the surface structure of ultra-thin film qualitatively as well as quantitatively, ALD processes are simulated with a molecular scale. For this simulation, the film materials are deposited on a imaginary substrate that consists of small lattice. The deposition behaviors are described by using random deposition (RD) model or random deposition with surface relaxation (RDSR) model as the ALD growth mode, and the proposed model was applied to the deposition of SrO-TiO₂ thin films. Through this work, growth characteristics such as surface morphology, deposited film
coverage can be predicted.

Selective laser sintering is a kind of rapid prototyping process whereby a three-dimensional part is built layerwise by laser scanning a powder. This process is highly influenced by powder and laser parameters such as laser power, scan rate, spot size and layer thickness. Therefore a study on fabricating a line with Fe-Ni-Cr powder on AISI H13 tool steel has been performed by selective laser sintering. In this study, fabrication was performed by experimental facilities consisting of a 200W fiber laser which can be focused to 0.08 mm and atmospheric chamber which can control atmospheric pressure with argon. The line was fabricated with various laser power, scan rate and layer thickness. Line width and surface quality were investigated. With power increase or layer thickness decrease, line width was decreased and line surface quality was improved with scan rate optimization.

Color stability of dental resin modified glass ionomer (RMGI) has been a challenge to dentistry; therefore, systematic changes in 2-hydroxyethyl methacrylate (HEMA) content were performed experimentally to find an idea to enhance the color stability. Changes in color ( ΔE_ab^*) and color coordinates (ΔL^*,  Δa^* and  Δb^*) of experimental 10-50 wt pct HEMA-added dental glass ionomers (HAGIs) and corresponding RMGIs were determined after 5000 cycles of thermocycling. Color changes of HAGIs were not influenced by the HEMA content while ΔL^*,  Δa^* and  Δb values were in°uenced by the HEMA content. Color stability of 30% or 40% HEMA-added HAGIs was not different from those of the commercial RMGIs. Since the in°uence of HEMA itself on the color stability of HAGIs was limited, compositional modi¯cation to increase the color stability of these materials should be developed.