Papers by Keyword: Interface

Abstract: In this paper, nano-Ti₃SiC₂/MoSi₂ composite, whose second phase was 20-150nm, was in situ prepared by mechanical activation (MA) and SPS process with the quaternary powers of Mo, Si, Ti, and C. The results showed that: (1) matrix MoSi₂ has strong repulsion to other elements, which leads to more second-phase particles inside the matrix rather than on the matrix surface; (2) matrix MoSi₂ has strong restriction on the growing of the second phase, which makes the particle diameter of the second phase inside the matrix only in 200 nm around, while that over the surface reaches to 800 nm around.

Abstract: Through the analysis of manufacture methods on molybdenum substrate target at home and abroad, method of powder metallurgy is put forward. Some factors affecting compound pressing are studied and discussed, among which, selective standards and requests of powder properties, compaction pressure, lubricant agents are detailed illuminated respectively. Demands for green compact densities of tungsten and molybdenum are brought forward after compound pressing in order to guarantee interfacial level-off and organic combination.

Abstract: In the domestic manufacturing enterprises, ERP application integration with other enterprise system has become a hot topic. In this paper we propose a new approach of visualization service integration based on ERP. Also, based on the actual needs of the system, a Visualization Interface is designed, in which programming is realized. This implement provides a reference for the similar visual integration.

Abstract: A CMOS integrated interface circuit for micro-machined gyroscope containing a novel front-end and 6th-order Sigma-delta modulator is presented in this paper. To reduce the noise coming from the sensor and circuit, the front-end is accomplished by a switched-capacitor architecture, which constructed by a high-gain fully-differential amplifier and improved by chopper-stabilization technique, and work under a designed charging and sampling logic scheme. A cascade 6th-order Sigma-Delta modulator is designed to get high resolution, reduce quantized error and suppress the instability brought by high-order modulator. With the cascade structure and 16-bit resolution 32 OSR, the modulator outputs 3-bits digital stream. The whole circuit is designed with AMS technique and 3.3V power consumption. The simulation result presents that the interface circuit performs a appointed under a low-noise design specification in signal band, and the SNR of the circuit achieves remarkable value of 106dB.

Abstract: Ni Base superalloys owe their excellent mechanical properties to the presence of particles of γ’ phase (Ni₃Al with an L1₂ struc­ture) in a g matrix (Ni–Al solid solution with an fcc structure). Besides Al, other elements are used to im­part either a higher strengthening or improved corrosion properties at high temperature. The interface between γ and γ’ becomes of absolute importance for the resulting mechanical properties and technological application. Especially by considering the consequences that diffusion driven coarsening brings about to the parti­cle distribution either with or without the influence of an applied stress or strain. In this work the interface between γ and γ’ phases is characterized by means of measurements on phase images obtained from high resolution transmission electron microscopy images (HRTEM). Phase images represent the sample structure much more accurately than typical HREM experimental images and allow correction of spherical aberration and other residual aberrations. The investigation is performed by using a binary Ni-Al alloy as well as technical Ni base superalloys (MC2 and MCNG). While a sharp interface is developed during stress free coarsening in Ni-Al alloys, a wider volume needs to be considered when alloying elements are introduced. Measurements of lattice spacings on phase images and chemical composition from energy dispersive spectroscopy are used to show the interface characteristics in the alloys under consideration. The interface in the binary Ni-Al alloy can be described by micro­mechanics as a typical misfitting inclusion. In the technical alloys, the presence of concentration gradients changes the expected lattice strains in a given volume around the particles.

Abstract: Explosive welding process is one of the effective methods in order to weld two dissimilar materials. Aluminum-steel composite was undergone heat treatments at temperatures between 2000C-5000C. In this study, the effects of explosive ratio and stand-off distance on the shape of the interface were studied. Moreover, the effects of various heat treatments on the interface strength are studied. The study shows that the type of the explosive, the magnitude of explosive ratio and standoff distance produces various interfaces with or without intermetallic compounds. The results show that effects of heat treatment on the aluminum-steel bond strength is depended upon the type and microstructure of straight, wavy and continuous melt produced at the interface. Moreover, the study shows that heat treatment gives rise to produce the brittle intermetallic compound of FeAl3 which lowers the weld strength. Having produced the smooth interface would reduce the heat treatment effects on lowering the weld strength.

Abstract: The phase field simulation of interface movement and interdiffusion microstructure in a binary diffusion couples was developed. The diffusion couples with nonequilibrium concentration for single phase or single phase and two-phase including the temperature and mobility effects were studied. It’s shown that the interface movement and the atoms diffusion direction were determined by the magnitude of relative concentration difference between the initial concentration and the equilibrium concentration, the distance of interface movement and interdiffusion flux increases as the temperature or the mobility increasing, and the large mobility makes the particles coarsening faster.

Abstract: PAN-carbon fibers were pretreated using three methods. 2D-C/C composites were fabricated by a rapid chemical liquid-vaporized infiltration (CLVI) processing. Surface morphologies of carbon fiber pretreated and fracture micrographs of 2D-C/C composites were observed by scanning electron microscopy (SEM) and high resolution transmission electron microscope (HRTEM). The interlaminar shear strength(ILSS) of C/C composites was tested. The influences of carbon fiber surface pretreatments on ILSS and fracture behaviors of C/C composites were analyzed. The experimental results indicated that the C/C composite with carbon fiber coated CVI pyrocarbon possesses both higher flexural strength and interlaminar shear strength than composites with other fiber pretreatments. The fractographes revealed the differences in the mechanical behavior depending on the interface strength of fiber/matrix.

Abstract: Ti, SiC and their composite materials have been widely used as high temperature structural material. The knowledge of interfacial stability between SiC and Ti is vital in high temperature applications. In this study, SiC/Ti diffusion couples were prepared to investigate the interfacial reactions between SiC and Ti at 1273 K. Phase forming sequence, microstructure and thermal stability of SiC/Ti interface were studied. It was indicated that after annealed at 1273 K for 10 days, 4 reaction layers were formed at the SiC/Ti interface. The diffusion path between SiC and Ti is SiC/Ti₃SiC₂/Ti₅Si₃/Ti₅Si₃+TiC/Ti₃Si/Ti. As the annealing time prolong, the thicknesses of these reaction layers increased.

Abstract: In this paper, a non-destructive analytical method was proposed to predict the serviceability of corroded RC structure from corrosion cracking. Two models of corroded reinforced concrete were proposed to take into account the influence of corrosion pattern. Based on a three-phase model linking corrosion cracking and reinforcement corrosion and the transfer length, the models allowed quantification of the effect of the steel cross-section loss and the deterioration of the steel-concrete bond. Using a macro-element FEM analysis, the serviceability models were performed on a corroded beam stored in a chloride environment under sustain loading to predict the deflection of mid-pan under service load and compare with the experimental results.