Papers by Keyword: Composite Interface

Abstract: A layered composite structural model with an outer wear-resistant layer of high-silicon aluminum alloy and an inner layer of ultra-high strength aluminum alloy is designed. A scaling brake drum part with layered composite was prepared by semi-solid precision forming process. The effects of process parameters such as casting temperature, specific pressure, solid layer temperature and heattreatment system on the composite interface were investigated. The results show that the casting temperature and solid layer temperature had a great influence on the interface recombination. The high forming specific pressure could effectively restrain the growth of secondary dendritesof the composite, and the proper heat treatment process could improve the morphology of the composite interface. A scaling brake drum component with A390/7050 layered composite structure was well prepared under optimal conditions.

Abstract: With the cladding casting equipment, which was self-designed and self-made, 4045/3003 composite ingot, which is in size of Φ140mm/Φ110mm, has been manufactured by direct cooling continuous casting by adjusting and optimizing the technological parameters. The process was investigated involving macro-morphology and microstructure near the interface between the two different aluminum alloys at different positions, and distributions of both components and hardness of the cladding ingot. In addition, the tensile strengths were tested. The results showed that metallurgical bonding of two different aluminum alloys could be obtained by direct-chill semi-continuous casting process. The diffusion layer, which is about 15μm on average, has formed on the two sides of composite interface during casting process. From the side of 4045 aluminum alloy to the side of 3003 aluminum alloy, the Si content has a trend to decrease, as well as the hardness, while the Mn content has a trend to increase gradually. Tensile strength of the coated ingot reaches 117.3MPa, which is higher than the core-material matrix (3003 aluminum alloy), indicating the bonding of the two alloys belongs to metallurgical bonding.

Abstract: The cross-linked polyethylene cable is largely used in power-supply system of the city. As the length of the power cable is concerned with the technology and construction, the center joint is largely employed, and the fault of the power cable is often found in the center joint. The discharge light has been seen on the face of the XPLE-SIR in work. The carbonization granule which appears after the discharge is the primary cause of the insulation degradation. A sample is designed, and the alternate electric-field rise on it to imitate the operational aspect. This paper analyses the relation of the discharge light, discharge current and carbonization granule. We find that it is feasible according to study the interface discharge light to deduce the characteristic of discharge and carbonization granule, and judge the degree of the interface insulation degradation.

Abstract: The experiment has taken composite algorithm of cold rolling to prepare copper and aluminum composite laminate, studied the influence of diffusion heat treatment on the interface of copper and aluminum composite laminate. After Analyzed the relationship between the thickness of diffusion layer and diffusion heat treatment parameters, the experiments show that diffusion heat treatment temperature and diffusion time has influence on formation and size of the diffusion layer. At the same heat treatment temperature, the thickness of diffusion layer has parabolic relation with diffusion time with diffusion time extending and thickness of diffusion layer increasing. And the thickness of diffusion layer is increasing at the same heat treatment time. And the thickness of diffusion layer has exponential relation with diffusion heat treatment temperature. Quantitative analyzed the relationship between diffusion heat treatment parameters and diffusion layer thickness, and established a formula to describe the interface thickness and diffusion of heat treatment temperature and time.

Abstract: The β-SiCp/Al electronic packaging composites with excellent performance were successfully fabricated by pressureless infiltration technology in air.The effects of alloying elements, infiltration temperature and time on infiltration process and application of -SiC were studied.The results show that by adding appropriate magnesium to aluminum matrix, a interface reaction between oxide films of SiC and magnesium occurs, and the interface reaction product MgAl2O4 is generated, the interface wettability of Al and SiC and pressureless infiltration are improved.The interface harmful phase Al4C3 can be inhibited by adding silicon to aluminum matrix.Identified 850°C for the best infiltration temperature, and the thickness with infiltration time and larger, infiltration rate is about 10mm/hour.Under the same parameter conditions, the thermal properties of β-SiCp/Al electronic packaging material are 4 ~ 6% higher than that of ɑ-SiCp/Al. The β-SiCp/Al electronic packaging materials with 66% SiC volume ratio has lower coefficiency of thermal expansion than those ɑ-SiCp/Al electronic packaging materials.And the thermal expansion coefficient and thermal conductivity of β-SiCp/Al electronic material can satisfy the requirements for electronic packaging materials.

Abstract: A method for manufacturing composite ingot of 4045/3004/4045 aluminum alloy using direct-chill (DC) casting was introduced. The casting process, the temperature distribution near the composite interface and the macro- and microstructures were investigated. The results show that composite interface is well-bonded, planar and clean with little evidence of porosity, which belongs to a kind of metallurgical bonding. Also semi-solid layer with a certain thickness is formed under the effect of cooling plate, which can ensure the realization of casting process of composite ingot.

Abstract: A method for manufacturing composite ingot of 3004/4045 aluminum alloy using direct-chill (DC) casting was introduced. The casting process, the temperature distribution near the composite interface and the macro- and microstructures were investigated. The results show that composite interface is well-bonded, planar and clean with little evidence of porosity, which belongs to a kind of metallurgical bonding. Also semi-solid layer with a certain thickness is formed under the effect of cooling plate, which can ensure the realization of casting process of composite ingot.

Abstract: The interface of fiber and matrix strongly influences the performance and strength of fiber-reinforced composite materials. Due to the limitations of continuum mechanics at the nanometer length scale, atomistic level computer simulation has started to play an important role in the understanding of such interfacial systems. Our study focuses on a typical crosslinked interfacial system of glass-epoxy composite with the presence of silanes. To explore the mechanical properties of the interfacial network system, Coarse-grained Molecular Dynamics is used. Currently it is not possible to study mechanical properties of interfacial systems purely through ab initio molecular dynamics simulations because of the huge computational resources required. Although pure atomistic classical molecular dynamics simulations have been used to study systems comprising billions of atoms, classical MD simulation do not take into account the effects of crosslinking of molecular chains. A new force field, which combines the Lennard-Jones potential and a finiteextensible nonlinear elastic attractive potential, is proposed and incorporated in a bead-spring model to simulate glass/epoxy interfacial system with the crosslinked structure of silanes. The finite-extensible nonlinear elastic attractive potential is included to control the motion and breakage of polymer chains. Interfacial adhesion and mechanical properties were studied through the simulation of mechanically separating the interfacial system.

Abstract: Fibers fracture in tensile strained Mg and MgLi matrix composites strengthened with ~10% vol. short δ-Al2O3 fibers (Saffil) is investigated by „in-situ“ scanning electron microscopy and ex-situ“ determination of the length of fibers chemically recovered from tensile failed composites. Little interfacial reaction in Mg matrix composite results in poor interfacial bond so that composite failure proceeds via fiber pull-out with negligible fiber fragmentation. On the other hand, extensive fiber/matrix reaction in MgLi matrix composites promotes formation of strong interfaces which are linked with multiple fiber cross-breakage during tensile straining. These results are consistent with experimental tensile strengths of related composites.