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The Hashin's criteria are useful in composite structural applications because of their simple concept and their theoretical results are relatively close to that got in the experimental parts. In the present study, in the present study, the failure of the composite laminates under static loading have been developed predicted using Hashin's Criterion. Nonhomogeneous stresses within a structure may induce a complicated failure scenario whereby one ply at a point can initiate failure and can affect also other plies at the same point or the same ply in different neighboring points. With neglecting the possibility of interlaminar failure, only in-plane loads are considered in this state. The results showed that the failure analysis was proposed to simulate the nonlinear laminate behavior and progressive damage of selected laminates under to their ultimate strength. In our approach, the finite element analysis is performed using MATLAB software to study the effect of tensile and compressive loading on the failure of epoxy resin laminate AS4/3501-6. [ABSTRACT FROM AUTHOR]

Using density functional theory (DFT), the equilibrium structural parameters, electronic, magnetic, and elastic properties of VMSb (M = Pd, Pt) half-Heusler compounds were investigated in this study. Calculations were performed using the full-potential linearized augmented plane wave (FP-LAPW) method, with the Wu-Cohen generalized gradient approximation (WC-GGA). Additionally, the electronic band structures and density of states were calculated using exchange and correlation potentials such as Tran-Blaha modified Becke-Johnson (TB-mBJ) and local spin density approximation with the on-site Coulomb interaction parameter U (LSDA+U). The theoretical results showed that the two half-Heusler compounds VMSb (M = Pd, Pt) exhibit half-metallic ferromagnetism with a total magnetic moment of 2.000 μB per formula unit, consistent with the Slater-Pauling rule. The electronic calculations revealed that VPdSb and VPtSb have spin-down band gaps of 0.45 eV, 0.51 eV and 0.54 eV, 0.58 eV, respectively, by LSDA+U, TB-mBJ. These half-Heusler compounds are promising candidates for potential applications in spintronic devices, as they offer an effective approach for magnetic and electronic appliances. [ABSTRACT FROM AUTHOR]

In this work, copper and zirconium were added into the Ti(Al)N matrix to form deposited on TiAl(Cu, Zr)N coating using RF magnetron sputtering system in order to improve the mechanical, wear performance, and antibacterial activity. Results revealed that the TiAl(Cu, Zr)N coatings have a dense structure with (111) preferential orientation. The deposited TiAl(Cu, Zr)N coatings exhibited fcc-TiN structure, whereas the addition of Zr and Cu into the Ti(Al)N induced the appearance of Cu and ZrN. The solid solution strengthening and the increase in compressive residual stress (− 2.54 GPa) of Ti(Al, Zr)N coating with higher lattice strain (+ 0.1520) by the addition of Zr improved the hardness from 20.9 GPa. For the tribological property, the friction coefficient and wear rate decreased from (0.45, 5.9 × 10−3mm3/Nm) for the TiAlN to (0.29, 4.2 × 10−5mm3/Nm) for the Ti(Al, Zr)N, respectively, with high elasto-plastic H/E, H3/E2 (0.076, 0.121 GPa) ratios due to the low surface roughness, high adhesion, and nanocomposite structure. The results indicated the addition of Zr improves the friction property of Ti(Al)N coating. Although with their lower hardness than Ti(Al)N coating, the Ti(Al, Cu)N coating with 9.2 at.% Cu exhibited an excellent wear resistance and good antibacterial activity, which demonstrates its potential as a candidate material for biomedical application. [ABSTRACT FROM AUTHOR]

In this study, simulation and experimental methods were used to investigate the influence of cold spray conditions on AISI 316L stainless steel coatings. The effect of both helium and nitrogen gases used was investigated. The temperature, particle sizes of spraying powder, and distance from the nozzle throat to the impinging point were estimated by using the Kinetics Spray Solutions GmbH software. The 316L stainless steel (SS) coatings were examined by X-ray diffraction, Scanning Electron Microscopy and Energy Dispersive X-Ray Microanalysis. The tribological behavior was evaluated under different loads (2 N and 5 N) in dry conditions. It was found that the nitrogen and helium propellant gas with high speed and fine particles led to produce good coatings with dense microstructures. From the nanoindentation experiments, the Young's modulus and hardness of the SS 316L samples were enhanced of about 8% with helium due to the high particle velocity. It was shown that the wear resistance of SS 316L produced with helium was higher than that of the standard SS 316L coatings. The coatings produced with helium revealed lower friction coefficient (0.65) and wear rate (6.9 × 10–4 mm3/Nm) under 2 N applied load than that obtained nitrogen. It was also found that the SS 316L cold sprayed by helium with dense structure presents high hardness and good tribological performance that can be suggested for several applications. [ABSTRACT FROM AUTHOR]

The structural, magnetic, electronic, optical and mechanical properties of lanthanum chromite LaCrO3 were investigated in cubic (Pm-3m) and orthorhombic (Pbnm) phases by the first-principles method based on the density functional theory. In this study, the WC-GGA with additional Hubbard potential U and Tran–Blaha-modified Becke–Johnson potential (TB-mBJ) were used. The structure optimization was accomplished for ferromagnetic (FM), A-type (A-AFM), C-type (C-AFM) and G-type (G-AFM). Both O-LaCrO3 and C-LaCrO3 phases were stable in the G-AFM state. The density of states and band structure revealed the existence of a wide band gap calculated with GGA + U and TB-mBJ, these two methods provide the accurate results for the band gap which are in good agreement with experimental values. The dielectric functions and optical proprieties were also calculated such as the absorption coefficient, refractivity index and the energy loss function. The elastic properties such as bulk modulus, shear modulus, Young's modulus and Poisson's ratio as well as the anisotropic factors were investigated. It has been shown that O-LaCrO3 and C-LaCrO3 phases were mechanically stable. Finally, the average sound velocity and the Debye temperatures of LaCrO3 were evaluated. [ABSTRACT FROM AUTHOR]

Magnetron sputtering is one of the most commonly used deposition techniques, which has received considerable attention in industrial applications. In particular, owing to its compatibility with conventional fabrication processes, it can produce and fabricate high-quality dense thin films of a wide range of materials. In the present study, nitrogen (N) was combined with pure vanadium in order to form binary nitride to improve its mechanical and tribological performance. To evaluate the influence of nitrogen on the structure of the as-deposited vanadium nitride (VN) coatings, the following techniques were used: XPS, XRD, SEM, AFM and optical profilometry. The residual stresses were determined by the curvature method using Stoney's formula. The hardness and Young's modulus were obtained by nanoindentation measurements. The friction behavior and wear characteristics of the films were evaluated by using a ball-on-disk tribometer. The obtained results showed that the N/V ratio increased with increasing the N2 flow rate while the deposition rate decreased. The preferred orientation was changed from (200) to (111) as the N2 flow rate increased with the presence of V–N and V–O binding energies as confirmed by XPS analysis. The nitrogen addition resulted in a columnar morphology and a fine structure with fine surface roughness. The VN thin film containing 49.5 at.% of nitrogen showed the best performance: highest mechanical properties (hardness = 25 GPa), lowest friction coefficient (μ = 0.37) and lowest wear rate (Ws = 2.72 × 10−5 mm3N−1 m−1). A good correlation between the film microstructure, crystallite size, residual stress and mechanical and tribological properties was observed. [ABSTRACT FROM AUTHOR]