Diffusion Bonding of Ti-6Al-4V to QAl 10-3-1.5 with Ni/Cu Interlayers

Ti-6Al-4V and QAl 10-3-1.5 diffusion bonding has been carried out with Ni/Cu interlayers. The diffusionbonded joints are evaluated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and microhardness test. Intermetallic compounds at the interface zone are detected by X-ray diffraction （XRD）. Interracial microstructure of TiNi＋CuTi3＋α-Ti forms at the Ni/Ti-6Al-4V transition zone and Cu （ss. Ni） solid solution forms between Ni/Cu interlayers. The thickness of reaction layer （TiNi） increases with bonding time by a parabolic law： y^2=Koexp（-150000/RT）t, and K0=2.g×10^-7 m^2/s is figured out from the experiment data.

Study on diffusion welding SiCp/ZL101 with Cu interlayer

Through the vacuum diffusion welding SiCp/ZL 101 aluminum with Cu interlayer,the effect of welding parameter and the thickness of Cu on the welded joint property wasinvestigated, and the optimal welding parameters were put forward at the same time. Themicrostructure of joint was analyzed by means of optical-microscope, scanning electron microscope inorder to study the relationship between the macro-properties of joint and the microstructure. Theresults show that diffusion welding with Cu interlayer could be used for welding aluminum matrixcomposites SiCp/ZL 101 successfully.

Polymer Solar Cells Using a PEDOT:PSS/Cu Nanowires/PEDOT:PSS Multilayer as the Anode Interlayer

We compare the electrical, optical, and surface properties of the PEDOT：PSS/Cu nanowires （Cu NWs）/PEDOT： PSS （PCP） multilayer for organic solar cells. It is demonstrated that the electrical and optical properties of the PEDOT could be improved by the insertion of a Cu NW layer due to its very low resistivity and surface morphology. The organic bulk heterojunction solar cell fabricated on the multil^yer exhibits a higher power conversion ef^ciency than devices based on the PEDOT：PSS or PEDOT：PSS/Cu NWs layer. Moreover, the PCP multilayer can improve cell-performances such as a fill factor and the internal resistance in the device due to horizontally well-aligned Cu NWs. The results suggest that the PCP multilayer is a promising low-cost and low-temperature processing buffer layer candidate for low-cost organic photovoltaics.

Preparation of diamond/Cu microchannel heat sink by chemical vapor deposition

A Ti interlayer with thickness about 300 nm was sputtered on Cu microchannels, followed by an ultrasonic seeding with nanodiamond powders. Adherent diamond film with crystalline grains close to thermal equilibrium shape was tightly deposited by hot-filament chemical vapor deposition(HF-CVD). The nucleation and growth of diamond were investigated with micro-Raman spectroscope and field emission scanning electron microscope(FE-SEM) with energy dispersive X-ray detector(EDX). Results show that the nucleation density is found to be up to 1010 cm-2. The enhancement of the nucleation kinetics can be attributed to the nanometer rough Ti interlayer surface. An improved absorption of nanodiamond particles is found, which act as starting points for the diamond nucleation during HF-CVD process. Furthermore, finite element simulation was conducted to understand the thermal management properties of prepared diamond/Cu microchannel heat sink.

Magnetic property and interlayer segregation in spin valve metal multilayers

The experimental results show that the exchange coupling field of NiFe/FeMn for Ta/NiFe/FeMn/Ta multilayers is higher than that for the spin valve multilayers Ta/NiFe/Cu/NiFe/FeMn/Ta.In order to find out the reason,the composition and chemical states at the surfaces of Ta(12nm)/NiFe(7nm),Ta(12nm)/NiFe(7nm)/Cu(4nm) and Ta(12nm)/NiFe(7nm)/Cu(3nm)/NiFe(5nm) were studied using the X-ray photoelectron spectroscopy (XPS).The results show that no elements from lower layers float out or segregate to the surface for the first and second samples.However,Cu atoms segregate to the surface of Ta(12nm)/NiFe(7nm)/Cu(3nm)/NiFe(5nm) multilayers,i.e.Cu atoms segregate to the NiFe/FeMn interface for Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers.We believe that the presence of Cu atoms at the interface of NiFe/FeMn is one of the important factors causing the exchange coupling field of Ta/NiFe/FeMn/Ta multilayers to be higher than that of Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers.

Effect of adhesive on laser-arc hybrid welding of aluminum alloy to high-strength steel joint

Aluminum alloy 6061 and high-strength steel Q460 were joined by laser-arc-adhesive hybrid welding technology successfully.A Cu alloy interlayer was added between Al alloy and high-strength steel.The effect of the adhesive on laser-arc-adhesive hybrid welding of Al alloy to high-strength steel was discussed.The optical microscope,scanning electron microscope and electron probe micro-analysis were applied to observe the microstructural evolution and phase transition at Al-Fe interface of laser-arc-adhesive hybrid welded joints.The results showed the maximum tensile shear strength of the joint without adhesive was 256 MPa.After adding adhesive,the maximum tensile shear strength reached 282 MPa.The combination of the mechanical bonding and the metallurgical effect could improve the mechanical performances.The shape of the joint in Al alloy changed into a canine-like morphology.There was no porosity in welds because the molten pool of Al alloy and the special keyhole phenomenon of laser welding provided a channel for the decomposed gas to escape from fusion zone.