Abstract The main purpose of this work is the description of dependence of the concentration of radiation displacements defects (RDD) induced by electrons and neutrons in garnets, perovskites, silicates, germanates, and tungsted bronzes type crystals (Y 3 Al 5 O 12 , Gd 3 Ga 5 O 12 , YAlO 3 , LiNbO 3 , Bi 4 Si 3 O 12 , Bi 4 Ge 3 O 12 , Ca 0.28 Ba 0.72 Nb 2 O 6 ) on the energy of particles by analytical function. The dependences were determined on the basis of calculations made using the Monte-Carlo method realized in the Atom Collision Cascade Simulation program. The results of calculations show that the concentrations of RDD reduced to one impinging particle increased initially with the particles energy and they saturates for the electron and neutron energy above 3–36 MeV, depending on crystal, sublattice and kind of irradiation particle. A wide range of energies for which the concentration of RDD is independent of the energy of particles (neutrons, electrons) makes them potential materials for the dosimetry of high-energy particles. The comparison of the concentrations of RDD calculated for different sublattices as well as for the cases of electrons and neutrons is made. In the case of irradiation with electrons, the relative concentration of RDD of the oxygen sublattice strongly depends on the energy of electrons and the crystal and varies in the range of 10–90%. In the case of neutrons, the relative concentration of RDD of the oxygen sublattice does not depend on the neutron energy and is in the range of 66–84% depending on the crystal.

Abstract The aluminium alloys 5052 and 6082 are extensively used in manufacturing lighter structural members, having improved strength and resistance to corrosion. Magnesium (Mg) and Chromium (Cr) powder were the filler materials selected for enhanced corrosion protection properties in this investigation. Friction stir welding (FSW) process parameters viz., spindle speed, welding speed, shoulder penetration, the centre distance between the holes and filler ratio are used to forecast the minimum corrosion rate from different weld regions of AA5052-AA6082 dissimilar joints. Response surface methodology based on a central composite design was used to evolve the mathematical models and estimate dissimilar FSW joints’ corrosion rates. Response optimization shows that the minimum corrosion rate was achieved by the welding parameters of spindle speed 1000 rev/min, welding speed 125 mm/min, holes spacing of 2 mm and filler ratio 95% of Mg and 5% of Cr.

Abstract Alloys of FeNiSiB soft magnetic materials containing variable Fe and Ni contents (wt.%) have been produced by melt spinning method, a kind of rapid solidification technique. The magnetic and structural properties of FeNiSiB alloys with soft magnetic properties were investigated by increasing the Fe ratio. X-ray diffraction analysis and SEM images shows that the produced alloy ribbons generally have an amorphous structure, together with also partially nanocrystalline regions. It was observed that the structure became much more amorphous together with increasing Fe content in the composition. Among the alloy ribbons, the highest saturation magnetization was obtained as 0.6 emu/g in the specimen with 50 wt.% Fe. In addition, the highest Curie temperature was observed in the sample containing 46 wt.% Fe.

Abstract A variety of tool shoulder designs comprising three families i.e. blade, spiral and circular shaped scrolls, were produced to improve the material flow and restrictions to avoid the tunnel void. The bobbin tools were manufactured by 3D printing additive manufacturing technology using solid filament. The butt weld joint was produced by each tool using plasticine as the workpiece material. The apparent surface features and bi-colour cross-sections provided a physical flow comparison among the shoulder designs. For the bobbin friction stir welding (BFSW), the tool shoulder with a three-spiral design produced the most stability with the best combination of the flow patterns on surface and cross-sections. The circular family tools showed a suitable intermixing on the surface pattern, while the blade scrolls showed better flow features within the cross-sections. The flow-driven effect of the shoulder features of the bobbin-tool design (inscribed grooves) was replicated by the 3D-printed tools and the analogue modelling of the weld samples. Similar flow patterns were achieved by dissimilar aluminium-copper weld, validating the accuracy of the analogue plasticine for the flow visualization of the bobbin friction stir welding.

Abstract In this work, nickel oxide was deposited on a glass substrate at by spray deposition technique; the structural, optical and electrical properties were studied at different NiO concentrations (0.05, 0.10 and 0.15 mol.l−1). Polycrystalline NiO films with a cubic structure with a strong (111) preferred orientation were observed at all sprayed films with minimum crystallite size of 11.97 nm was attained of deposited film at 0.1 mol.l−1. However, α-Ni(OH)2 was observed at 0.15 mol.l−1. The NiO thin films have good transparency in the visible region, the band gap energy varies from 3.54 to 376 eV was affected by NiO concentration, it is shown that the NiO thin film prepared at 0.05 mol.l−1 has less disorder with few defects. The NiO film deposited at 0.15 mol.l−1 has the electrical conductivity was 0.169 (Ω.cm)−1.

Abstract The purpose of this study is to elucidate the flow features of the dissimilar Al-Cu welded plates. The welding method used is Bobbin Friction Stir Welding (BFSW), and the joint is between two dissimilar materials, aluminium alloy (AA6082-T6) and pure copper. Weld samples were cut from along the weld line, and the cross-sections were polished and observed under an optical microscope (OM). Particular regions of interest were examined under a scanning electron microscope (SEM) and analysed with Energy Dispersive X-ray Spectroscopy (EDS) using the AZtec software from Oxford Instruments. The results and images attained were compared to other similar studies. The reason for fracture was mainly attributed to the welding parameters used; a higher rotational speed may be required to achieve a successful BFSW between these two materials. The impact of welding parameters on the Al-Cu flow bonding and evolution of the intermetallic compounds were identified by studying the interfacial microstructure at the location of the tool action. The work makes an original contribution to identifying the solid-phase hybrid bonding in Al-Cu joints to improve the understanding of the flow behaviours during the BFSW welding process. The microstructural evolution of the dissimilar weld has made it possible to develop a physical model proposed for the flow failure mechanism.

Abstract The investigation into wear resistance is an up-to-date problem from the point of view of both scientific and engineering practice. In this study, HVOF coatings such as MCrAlY (CoNiCrAlY and NiCoCrAlY) and NiCrMo were deposited on AISI 310 (X15CrNi25-20) stainless steel substrates. The microstructural properties and surface morphology of the as-sprayed coatings were examined. Cavitation erosion tests were conducted using the vibratory method in accordance with the ASTM G32 standard. Sliding wear was examined with the use of a ball-on-disc tribometer, and friction coefficients were measured. The sliding and cavitation wear mechanisms were identified with the SEM-EDS method. In comparison to the NiCrMo coating, the MCrAlY coatings have lower wear resistance. The cavitation erosion resistance of the as-sprayed M(Co,Ni)CrAlY coatings is almost two times lower than that of the as-sprayed NiCrMoFeCo deposit. Moreover, the sliding wear resistance increases with increasing the nickel content as follows: CoNiCrAlY < NiCoCrAlY < NiCrMoFeCo. The mean friction coefficient of CoNiCrAlY coating equals of 0.873, which almost 50% exceed those reported for coating NiCrMoFeCo of 0.573. The as-sprayed NiCrMoFeCo coating presents superior sliding wear and cavitation erosion resistance to the as-sprayed MCrAlY (CoNiCrAlY and NiCoCrAlY) coatings.

Abstract Carbon fiber has been used to reinforce both aliphatic and aromatic polyamides. Aliphatic polyamide is known as nylon and aromatic polyamide is often referred to as aramid. Among aliphatic polyamides, polyamide 6, polyamide 6,6, polyamide 11, polyamide 12, and polyamide 1010 have been used as matrices for carbon fiber. Factors affecting the properties of polyamide/carbon fiber composites are: fiber amount, fiber length, fiber orientation, matrix viscosity, matrix-fiber interactions, matrix-fiber adhesion, and conditions encountered during manufacturing processes. This article presents a state-of-the-art review on polyamide/carbon fiber composites. Polyamide/carbon fiber composites are lightweight and exhibit high strength, modulus, fatigue resistance, wear resistance, corrosion resistance, gear, electrical conductivity, thermal conductivity, chemical inertness, and thermal stability. Incorporation of oxidized or modified carbon fiber and nanoparticle modified carbon fiber into polyamide matrices have been found to further enhance their physical properties. Applications of polyamide/carbon fiber composites in aerospace, automobile, construction, and other industries have been stated in this review. To fully exploit potential of polyamide/carbon fiber composites, concentrated future attempts are needed in this field.

Abstract In this study, it was aimed to synthesize hydrogel based antibacterial, biocompatible and non-toxic wound dressing materials by solvent removal method usingpoly(vinylalcohol) (PVA), poly(vinylpyrolidone) (PVP) and nano pomegranate seed (PN).The morphology, swelling capacity, contact angle, antibacterial activity, biocompatibility and cytotoxicity of the synthesized films were determined. From the experimental findings, it was found that the PN particles were nano-sized, showed homogeneous and spherical distribution and improved the hydrophobic properties of the materials obtained by the addition of PN. And also, their swelling capacities were decreased with increased PN amount and all of the materials showed similar antibacterial activity, hemocompatibility and cytotoxicity.

Abstract The degradation of materials due to slurry erosion is the serious problem which occurs in the power industries. The paper presents actual knowledge about an influence of individual factors connected with flow conditions, particles and material properties on the slurry erosion resistance. Among the factors connected with operating conditions, an influence of impact angle, and velocity of impact, particle concertation and liquid temperature have been described. In case of the factors connected with solid particle properties, an influence of the size, shape and hardness have been discussed. In the part devoted to the impact of material properties, due to different types of materials, the issues of resistance to erosion of slurries related to the properties of steel, ceramics and polymers are discussed separately. In the paper has been shown that a change of any of mentioned factors causes a change in the erosion rate due to the synergistic effects that accompany to slurry degradation.