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The effects of pressure on the mechanical and dynamical stability of NaAlSi have been fully investigated by first-principles calculations within the generalised gradient approximation (GGA). The ob...

The well-known general solution for uncoupled thermoelasticity of isotropic bodies was proposed by Goodier, which has been utilized extensively since its birth in 1937. When the steady-state respon...

In this paper, a numerical method is proposed for solving nonlinear variable-order space fractional diffusion equations. The method is based on the reproducing kernel theory and the iterative method. The convergence of the method is also discussed. Numerical examples are provided to show that the numerical method is computationally efficient.

Based on two sets of TiAl powder, two kinds of porous TiAl were separately fabricated by powder metallurgical route including four stages. The porous TiAl with single pore structure (SPS) was prepared using pre-alloyed TiAl powder prior mechanical ball milling. Another porous TiAl with composite pore structure (CPS) was manufactured depending on composite mixture of Ti/Al elemental powders. The sintering was achieved at much lower temperature for the pre-alloyed power than for the elemental composite mixture. Compressive mechanical tests indicate that much higher mechanical strength can be obtained for SPS than for CPS at the same porosity. It was suggested that the difference of mechanical properties is ascribed to the variety of the compressive deformation process.

Two-liquid bimetal casting technique was worthy of being widely used in wear-resistant materials. Research on the fusion mechanism at the bimetal composite layer can lay the theoretic foundation for the extension of the dissimilar ferroalloy composition material. Two-liquid bimetal between the low-alloy steel and high-chromium white cast was prepared by controlling the pouring temperature, and the composite layer microstructure and composition distribution were studied. In accordance with the detected results, two-liquid bimetal casting technique can be assured, and the various casting technique parameters have an obvious effect on the composite layer microstructure. To maintain the casting technique stability, the freezing time and element diffusion of the low-alloy steel were evaluated and analysed.

The hot deformation behaviour depends on the initial texture. In this study a hot rolled Zr alloy plate with a bimodal basal texture has been compressed at 700°C along two directions to study the effect of initial texture on deformation mechanisms and dynamic recrystallisation (DRX). Four strain levels (10, 20, 30 and 45%) of uniaxial compression were analysed. Microstructures and textures of deformed specimens were characterized and compared by electron backscatter diffraction (EBSD). At 10% strain, twins were observed in the two textures, but {10–12} tensile twins predominate in the sample with the bimodal basal texture normal to the compression direction. As the compression strain accumulates to 20%, DRX is also affected by the initial texture. When the c-axis is close to the compression axis (CA), extensive DRX process was observed. If the c-axis is perpendicular to the CA, DRX was obviously retarded. Due to the initiation of twinning, the stored energy accumulated by dislocations was relative...

Because of their superior mechanical properties and high corrosion resistance in aqueous environments, duplex stainless steels are the material of choice for equipment used in the off-shore gas and oil industry. However, wear in chloride containing water (i.e. corrosion wear) is considered as a major concern. During the past decade, a new low temperature plasma surface alloying technique has been developed to achieve combined improvements in hardness, wear resistance and fatigue properties of austenitic stainless steels, without impairing their corrosion behaviour due to the formation of S-phase. However, few researchers have applied this technique to duplex stainless steel (DSS) and no work has been reported for super DSS (SDSS). In this paper, SDSS 2507 has been DC plasma nitrided under a range of treatment conditions. Energy dispersive X-ray spectroscopy (EDX), Glow discharge Spectrometry (GDS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterise the microst...

A new theoretical equation that describes the thermal conductivity of a two-phase composite is proposed. The Cheng–Vachon equation has been modified, and a new parameter, i.e. the modified volume fraction, is introduced. The modified volume fraction is a function of the physical volume fraction and thermal conductivity ratio of constituent phases. It was found that the new equation can describe the thermal conductivity of different two-phase composites, such as Cu/solder, Al/water, Al/air and cellular concrete, very accurately.

A series of β-cyclodextrin (β-CD) derivatives modified by l -cystine, including 3,3′- l -cystine-bridged bis(β-CD) (2), 3- l -cystine-β-CD (3), 6,6′- l -cystine-bridged bis(β-CD) (4) and 6- l -cystine-β-CD (5), were synthesised in moderate yields by the reaction of l -cystine with mono-[2-O-(p-tolysulfonyl)]-β-CD (2-O-Ts-β-CD) or mono-[6-O-(p-tolysulfonyl)]-β-CD (6-O-Ts-β-CD). Their binding manners and inclusion abilities towards some dye guests (ANS, TNS, AR, NR, EY and FL) were, respectively investigated by the methods of 2D NMR spectrometry and fluorescence spectrometry in aqueous solution (pH 7.2). The results obtained show that the stoichiometric 1:1 complexes formed by l -cystine modified β-CD monomers and dimers 2–5 with dye guests give higher complex stability constants (K S) than those of native β-CD. In addition, the difference of inclusion complexation between primary-side and secondary-side modified/bridged β-CDs was compared in detail and discussed from the viewpoint of inclusion orientation,...

The dielectric and ferroelectric properties for Au/Pb(Zr,Ti)O3/YBa2Cu3O7−x heterostructures at low temperatures are reported. The fatigue behavior and the ferroelectric switching effect for the structures are also investigated. The PZT/YBCO thin film heterostructures were deposited on MgO(100) substrates by laser ablation. The ferroelectric and dielectric properties and optical response of the oriented PZT films with different thicknesses have been studied over the temperature range from 20 K to 300 K. The dielectric loss of the structure was found to decrease by an order of magnitude when the YBCO bottom electrode became superconducting. A very low fatigue rate of the structure has also been obtained below T c of YBCO layer.