Solid State Phenomena Vol. 345

Abstract: Copper-Nickel-Tin alloys have been recently developed by Hardening due to spinodal decomposition. The (Cu - 9Ni - 6Sn) system has shown promise in this direction and has been used to develop several high strength compositions. It is well known the fact that small element additions significantly modify phase transformation characteristics, the effect of adding Silicon or Silver on the Spinodal hardening in (Cu - 9Ni - 6Sn) alloy was studies close to the Spinodal cusp temperature. The presence of Silver also increased the ductility of alloy at the expense of some hardness. The effects of trace elements additions have been observed in this work with a view to improve high strength alloys as substitutes to the Copper – Beryllium alloys. The results obtained from the current research proved that adding a small amount of alloying elements with a percentage (1%) of silicon or silver to the base alloy (Cu - 9% Ni - 6% Sn), led to the stability of the mechanical properties resulting from the stability of the microstructure due to Heat treatment for hardening (Spinodal decomposition).

Abstract: In this work, the preparation and processing of aluminum-copper alloys, which added amounts of copper to aluminum in different parentages (2, 4, 5%) so that it does not exceed the saturation limit for aluminum (6% Copper). After adding these specific amounts of copper to aluminum, have been melting each alloy to thaw copper in aluminum fully and diffusion copper atoms in it, and after that the specimens were prepared and quenched at 8-30 hours and rapid cooling in the water, and then were studied parameters of heat treatment and different percentages of copper. It is clear from the schemes and experimental results that each weight ratio of copper in aluminum has a different approach to reach the best mechanical properties. After performing mechanical tests and tests, it was found that the highest hardness of the (aluminum-copper) alloy in the case of (2% Cu) amounted to (120 HB) and in the case of (4% Cu) the amount (211 HB) and in the case of (5% Cu) the amount (188 HB).

Abstract: Fused Deposition Modeling (FDM) is an Additive Manufacturing technology where a heated plastic filament will be placed on the bedplate layer by layer until the 3D object is printed. The mechanical properties of the ABS FDM 3D-printed parts are not yet determined or estimated prior printing. Hence, the goal of this study is to identify the optimum 3D printing parameters based on the tensile properties of ABS FDM 3D-printed polymer parts. Taguchi approach and Range Analysis were used in finding the optimum 3D printing parameters in which different parameters were considered to meet the requirements of the orthogonal arrays. Five pieces of 3D-printed dumbbell-shaped tensile specimen were prepared for each parameter. The tests followed the ASTM D638-14 standard. The result for the optimum 3D printing configuration of ABS FDM 3D-printed material were concluded as the values with the highest tensile strength.

Abstract: This work presents the preparation of mechanically exfoliated graphene-CMC biocomposite ink which was utilized in the printing process of SC individual electrodes via InkJet printing (IJP) technique. Three individual electrodes were fabricated using such technique with high abilities to control the geometry and tuning both resulting sheet resistance and thickness. The printer showed a good command of printing computer-aided designs with high resolution and fabricated well-homogenised patterns. The electrochemical behaviour of the fabricated electrodes was investigated in 0.1M NaOH. Results illustrate that electrodes have shown good capacitive behaviour and EDLC was the main energy storage mechanism. There was a direct relationship between the number of the printed layers and the resulting electrical parameters. A maximum areal capacitance of 16.58 mF/cm² was achieved with printing 80 layers. Such results indicate that the formulated ink would be potential for electrochemical energy storage applications.

Abstract: Laser powder bed fusion manufactured (PBF-LB) austenitic stainless steel 316L offers higher strength than traditionally manufactured counterparts. Further improvement can be obtained with suitable surface modification. This work focuses on improving the material qualities with the aid of severe shot peening (SSP), which can increase the surface hardness, reduce roughness and produce grain refinement and compressive residual stresses on the surface. These qualities are all beneficial for the fatigue life of the material. Material was studied in two conditions: as built and heat treated (HT) at 1100 °C and the effect of SSP on both. The results showed clear microstructural changes on both structures leading to increased strength. The fatigue strength of as built material benefits greatly from the SSP treatment, but when performed on a high temperature HT material the benefits are negligible. However, in applications where the parts are subjected to bending forces the surface modification plays a role also with the HT material.

Abstract: The Non-Fermi-Liquid (NFL) state has been one of central issues in the strongly correlated electrons systems. This deviates from conventional Fermi Liquid (FL) behavior. In the hole-doped triangular lattice organic metal κ-(ET)₄Hg_3-δBr₈, δ = 11% (κ-HgBr), the NFL state is observed as a linear temperature dependence of the resistivity which changed to the temperature square dependence behavior by pressure. The spin susceptibility dependence of the muon Knight shift, K(c), is not linear in the region below 50 K, unlike in other k-type organic superconductors. Furthermore, ¹³C-NMR study under pressure concluded that strong antiferromagnetic spin fluctuations (AFSF) contribute to the origin of NFL. To understand the underlying correlation of the enhanced AFSF and NFL state in k-HgBr, the K(c) plot study in the sister compound κ-(ET)₄Hg_3-δCl₈, δ=22% (κ-HgCl) which shows metal to insulator transition at T_MI ~ 20 K is desirable. In this study, we report a precise susceptibility measurement in both k-HgBr and k-HgCl. Furthermore, we summarize the c(T) data of k-HgBr and k-HgCl and discuss them from the viewpoint of the triangular and square lattice models.

Abstract: We have investigated the magnetism and superconductivity of the electron-doped Eu_2-xCe_xCuO_4+α-δ in a wide range area of doping Ce⁴⁺ at 0.09 ≤ x ≤ 0.20 by means of magnetic susceptibility measurement at low temperatures down to 2 K. Superconductivity was observed in the concentration of Ce⁴⁺ at 0.12 ≤ x ≤ 0.20 with the range of the reduction of oxygen content 0.0255 ≤ δ ≤ 0.093 with a maximum transition temperature of 12 K. Furthermore, from the data temperature dependence of the dc magnetic-susceptibility, it can be analyzed the Curie constant, atomic magnetic moment and effective magnetic moment in each sample. Those three values have similar values with increasing Ce⁴⁺ concentration for a sample that doesn’t show superconductivity.

Abstract: (1-x)BiFeO₃-xBaTiO₃-0.01KVO₃ with (x = 0.33 and 0.38) (abbreviated FTV33 and FTV38) was successfully prepared using three precursors that had been synthesized before the calcination process. BaTiO₃ was synthesized using the coprecipitation method, BiFeO₃ was synthesized using the sol-gel auto-combustion method, and KVO₃ was synthesized using the conventional solid-state method. Thermal analysis was carried out to determine the calcination temperature from 600 0C for 2h to 600 0C for 4h. X-ray diffraction (XRD) has been carried out to identify the phase after calcination at temperatures, respectively. The phase identification of the XRD pattern has been carried out by Match software shows that the powder and FTV33 and FTV38 have a pseudo-cubic structure with a P4mm space group and rhombohedral with an R3c space group. The XRD pattern is refined by the Rietveld method by Rietica software and the crystalline size is determined by MAUD software. The doping effect of KVO₃ on its electrical properties was systematically investigated and show that FTV33 is more conductive and has larger capacitance grains. Based on the previous XRD analysis, Ba²⁺ and K⁺ ions replaced Bi³⁺ at site A. On the other hand, Ti⁴⁺ and V⁵⁺ substituted Fe³⁺ at site B which was different from the host's oxidation state.

Abstract: Structure, morphology, and magnetic properties of perovskite La_0.7Sr_0.2Ba_0.1Mn_1-xCr_xO₃ (x = 0; 0.03; 0.05; 0.07 and 0.1) synthesized via sol-gel method have been studied. X-ray diffraction studies confirm the Rhombohedral structure with R-3c space groups for all samples. The magnetization measurements clearly show that magnetization decreases with increasing Cr substitution concentration. The partial substitution of Cr³⁺ in the Mn site weakens the ferromagnetic double exchange interaction of the Mn³⁺–O–Mn⁴⁺ bond. It is caused by the emergence of the Cr³⁺–O–Cr³⁺ antiferromagnetic interaction. As known, the structural parameters affect the magnetic properties of perovskite manganese materials in the double exchange interaction. As the Cr³⁺ concentration increases, the average Mn-O bond length also increases, and the average Mn-O-Mn bond angle decreases, which dramatically weakens the Mn³⁺–O–Mn⁴⁺ double exchange interaction.