The present study deals with the effect of cold deformation and subsequent aging on the microstructure and mechanical properties of Al-Cu-Si-Mg alloy. Differential scanning calorimetry indicates that precipitation occurs in the temperature range of 258−272°C for the as quenched wrought alloy. The activation energy value estimated by Kissinger method for the aforesaid precipitation reaction is obtained as 106 kJ/mol. 45% cold deformation prior to aging indicates the first dissolution reaction at about 50°C and the precipitation reaction at a temperature of about 82°C. Microstructural investigations have revealed the formation of fine precipitates within the matrix after aging of the cold deformed sample. As-quenched alloy reveals prominently the aging
response. The increase in hardness, yield and tensile strength with simultaneous decrease in elongation in the deformed alloy is found to be primarily due to the deformation strengthening and not due to the precipitation hardening.

For the purpose of improving the strength of this dissimilar joint, the present study was carried out to investigate the improvement in intermetallic layer by using a third material foil between the faying edges of the friction stir welded and hybrid welded Al6061-T6/AZ31 alloy plates. The difference in  icrostructural and mechanical characteristics of friction stir welded and hybrid welded Al6061-T6/AZ31 joint was compared. Hybrid buttwelding of aluminum alloy plate to a magnesium alloy plate was successfully achieved with Ni foil as filler material, while defect-free laser-friction stir welding (FSW) hybrid welding was achieved by using a laser power of 2 kW. Transverse tensile strength of the joint reached about 66% of the Mg base metal tensile strength in the case of hybrid welding with Ni foil and showed higher value than that of the friction stir welded joint with and without the third material foil. This may be due to the presence of less brittle Ni-based intermetallic phases instead of Al12Mg17.

This paper describes pre-treatment methods to improve the bake-hardening response of naturally aged AA6022 (Al-0.6Mg-1.0Si), which is an alloy used in automotive body panels. These methods are used to accelerate the artificial aging process, which proceeds 30-day period of natural aging. The  precipitation behavior of the sheets of this aluminum alloy was analyzed by differential scanning calorimetry (DSC) and electrical conductivity measurements, and subsequently confirmed by microstructure observations by transmission electron microscopy (TEM). Tensile tests and microhardness measurements were performed to determine the mechanical properties of the samples. Under simulated paint-baking conditions (30 min at 170°C), the microhardness and the yield strength (YS) of the pre-strained + pre-aged samples were found to be 113 HV and 225 MPa, respectively. These values are considerably higher than those of pre-aged samples, and they did not decrease significantly during the initial stage of artificial aging.

Structural and dielectric properties of polycrystalline samples of lead-free (1-x)(Na_1/2Bi_1/2)TiO_3-xZnO, prepared using a high-temperature solid-state reaction method, are investigated in the composition range 0 ≤ x ≤ 0.10. Rietveld analyses of X-ray diffraction data indicated the formation of a single-phase hexagonal structure with R3c symmetry. Williamson-Hall approach was applied to estimate the apparent particle size and lattice strain of the compounds. Temperature dependence of dielectric constant showed that the addition of ZnO to (Na_1/2Bi_1/2)TiO₃ shifts the phase transition temperature towards higher side, a property favourable for practical applications of these ceramics. Further, temperature dependent permittivity data provided low temperature coefficient of capacitance (T_CC < 8%) up to 100°C. Furthermore, a decrease in the value of dielectric loss with an increase in ZnO content is observed.

Exchange coupling and magnetic properties of SmCo₅ alloys containing different amounts of Sn were investigated in sintered magnets. X-ray diffraction analysis revealed the formation of Sm₂Co₁₇ and Sm₂Co₇ phases in SmCo₅ matrix. Exchange coupling mechanism was evaluated by switching field distribution, dc-demagnetization and magnetization curves as function of reverse applied field. Energy product of 59.2 kJ/m³ (7.4 MGOe), remanent magnetization to maximum magnetization ratio of 0.97 and remanence coercivity to intrinsic coercivity ratio of 1.75 were achieved for 0.2 at.% Sn.

The manganite La_0:67Sr_0:33MnO₃ (LSMO) thin films were grown on glass substrates in a mixed argon and oxygen atmosphere by using RF magnetron sputtering. The structural characteristics, transport behaviors and magnetic properties of LSMO films were studied by annealing the films in air at 550 and 620°C. The out-of-plane lattice parameter aLSMO contracted after annealing and was close to that of bulk LSMO abulk, indicating that the internal strain was fully relaxed. Nanocrystalline grains were observed in the annealed films. Enhanced saturation magnetization and metal-to-insulator transition temperature (T_MI=268 K) were also obtained. Curie temperatures (T_c) of the as-grown films was 340 K with the same as that of annealed at
550°C, but dropped to 315 K when the annealing temperature increased to 620°C, which can be attributed to the oxygen release during annealing in atmosphere.

Here we report the fabrication and superconductivity of the iron-based arsenic oxide SmO_1-xF_xFeAs compound. X-ray diffraction (XRD) results prove that the lattice parameters a and c decrease systematically with increasing x in between 0<x≤0.35, but when x>0.35 the a and c increase with the decrease of x in
the SmO_1-xF_xFeAs. The critical temperature (T_c) increases with increasing x in between 0.15≤x≤0.3, while x>0.3 the T_c decreases with the increase of x. It is found that at x=0.3 SmO_0.7F_0.3FeAs has the highest onset resistivity transition temperature of 55.5 K. The critical current density (J_c) value at 10 K for the obtained SmO_0.7F_0.3FeAs is 1.3×10⁵ A/cm² (0 T). Meanwhile one can estimates H_c2(0) from the slope of the H_c2(T) curve at T=T_c (H_C2 is the upper critical field), and for the 90% normal-state resistivity (ρ_n) criterion (T_c=55 K), H_c2(0) is determined to be ~253 T.

Oleylamine (G18) and octanol (G8) were grafted onto the surfaces of the multi-walled carbon nanotubes (CNTs). The grafted CNTs were dispersed into palmitic acid (PA) and paraffin wax (PW) to prepare phase change composites. The heat storage/retrieval experiments showed that the composites kept stable after repeating melting and solidification for 80 times. The structure of the G18-CNT/PA and G8-CNT/PA was homogenous compared with the pristine CNT (P-CNT)/PA. The latent heat capacity (Ls) of solid liquid phase change of G18-CNT/PW was higher than that of PW while those of the G8-CNT/PW and P-CNT/PW were lower than that of PW. Compared with PA, all PA based composites with both P-CNTs and grafted CNTs decreased Ls evidently. The Ls values of G18-CNT composites in both matrices were higher than that of the counterparts of G8-CNT. The thermal conductivities of all the PA based composites in the study were higher than that of PA, as well as those of all the PW based composites. However, the thermal conductivities of the
G18-CNT composites in both matrixes were lower than those of the G8-CNT composites in both matrixes at all measured temperatures.

This paper described a process for synthesizing a new multiphase TiC/Ti₂AlC/TiAl₃ composite, in which Ti, Al₄C₃ and graphite powders were utilized as raw materials, and in situ spark plasma sintering-reactive sintering (SPS-RS) methods were involved. The intermediate phases of Ti₃Al and TiAl were found during the reactive sintering process and the reactions for the phase's formation were proposed. The microstructure and mechanical properties of the composites were investigated. The high-resolution transmission electron microscopy (HRTEM) image of the interface showed that no amorphous phases were detected along the grain boundary. The orientation relationships between the Ti₂AlC and the TiC were shown to be (0001)Ti₂AlCjj(111)TiC and
[1210]Ti₂AlC||[110]TiC. The average hardness, fracture toughness, Young's modulus and bending strength of the composite were 15.1±0.8 GPa, 4.9±0.3 MPa?m^1/2, 261±13 GPa and 776±18 MPa, respectively. The toughening mechanism was also discussed.

Graphite-like carbon nitride (g-C₃N₄) was synthesized in large quantities at 300ºC under nitrogen by a solidstate reaction route. Furthermore, Al³⁺ and Mg²⁺ intercalation of g-C₃N₄ was performed by an electrochemical method. The starting C₃N₄ materials and intercalation compounds were characterized by X-ray powder diffraction, Fourier transform infrared spectra, thermogravimetry, transmission electron microscopy, and X-ray photoelectron spectroscopy. The possible structure model of intercalation compounds was proposed. The cation-¼ interactions and electrostatic interactions were used to explain the changes of microstructure and chemical bonds before and after intercalation.

The relation between the Mg treatment and ferrite grain boundaries misorientation was investigated. The orientation imaging microscopy technique based on electron backscattered diffraction technique (EBSD) was used in this work. It was found that the addition of 0.005 wt% Mg to the steel could evidently increase the ratio of acicular ferrite crystals appearing at large angles boundaries to each other, which was attributed to the nucleation of the second-phase particles by the Mg treatment. The EBSD techniques provide a powerful method to characterize and quantify the ferrite grain boundaries misorientation, in order to relate it to toughness.

Strain-induced martensites in high manganese TRIP/TWIP steels were investigated in the presence of thermal martensites and under the influence of austenitic grain orientation by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD). Before deformation, the morphology of α'-M depended mainly on the number of variants and growing period. Regardless of martensite morphologies and
deformation, the Kurdjumov-Sachs (K-S) orientation relationships always maintained. The 6 α'-M variants formed from a plate of ε-M were of 3 pairs of twins with a common axis <110>_α' parallel to the normal of {111}_γ habit plane to minimize transformation strain. When α'-M could be formed only by deformation, it nucleated at the intersection of ε-M variants and grew mainly in thick "-M plates. Thick " plates promoted significantly the α'-M and weakened the influence of grain orientations. During tension, the transformation in <100>-oriented grains was observed to be slower than that in <111>-oriented grains. Deformation twins promoted ε-M formation slightly and had no apparent effect on α'-M. Deformation increased the number of "-M variants, but reduced that of α'-M variants.

The catalytic graphitization of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate (FN) was studied in detail. The morphologies and structural features of the products including onion-like carbon nanoparticles and bamboo-shaped carbon nanotubes were investigated by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction and Raman spectroscopy measurements. It was found that with the changes of loading content of FN and residence time at 1000°C, the products exhibited various morphologies. The TEM images showed that bamboo-shaped carbon nan-otube consisted of tens of bamboo sticks and onion-like carbon nanoparticle was made up of quasi-spherically
concentrically closed carbon nanocages.

Single crystals of β-Naphthol (βN), an organic nonlinear optical (NLO) material was successfully grown by temperature lowering method using chloroform as solvent. The initial compound was purified by repeated recrystallization process. As-grown crystals were characterized by single crystal X-ray diffraction (XRD) studies to ascertain that βN crystal crystallized in the monoclinic system with a noncemtrosymmetric space group. Vibrational frequencies of various functional groups in the crystals were derived from Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (NMR) spectrum. Optical characterization was done using UV-Visible near-infrared (NIR) spectroscopy. The thermal behaviour of the material was studied by thermo gravimetric and differential thermal plots. Scanning electron microscopy (SEM) study was carried out on the surface of the grown crystals to investigate the nature of defects in the crystal surface and the NLO property of the crystal was tested by Nd:YAG laser as a source.

In this paper, the crystallization behaviour of amorphous Cu56Zr7Ti37alloy using thermal electrical resistivity (TER) and differential scanning calorimetry (DSC) studies has been described. Isochronal TER and DSC measurements indicate that crystallization occurs in two stages. Isothermal crystallization studies of the alloy by TER show that the kinetics conforms to Johnson-Mehl-Avrami model. Avrami exponents derived from kinetics, between 1.1 and 1.2, imply that the crystallization processes are diffusion controlled with near zero nucleation. Activation energy has been found to increase with the transformed volume fraction. A plausible explanation has been presented by separating the contributions due to nucleation and crystal growth towards total activation energy.

Multilayered Pt/Ru modified aluminide coating for thermal barrier coating (TBC) systems has been investigated. 2 μm Pt+2 μm Ru+2 μm Pt was first deposited on nickel-base superalloy DZ125 by electrodeposition, and then the coating was treated by annealing and a conventional pack-cementation aluminizing process. The cyclic oxidation tests were carried out at 1423 K in air. It was found that the thermal cyclic oxidation resistance of Pt/Ru-modified aluminide coating was comparable to that of Pt-modified aluminide coating, which was much better than simply aluminized DZ125. The addition of Ru to Pt-modified aluminide coating increased the resistance to rumpling. The microstructures and phase constitutions of the coating before and after oxidation were investigated.