Papers by Keyword: Intermetallic Compound (IMC)

Abstract: The AuSn20 (mass fraction) solder was prepared by laminate rolling-annealing method, the AuSn20/Ni solder joints were prepared by the reflow process. The effects of the aging times and temperatures on the microstructure and shear strength of the AuSn20/Ni joints were investigated by the scanning electron microscope (SEM) with an energy dispersive X-ray (EDX). The results show that, the AuSn20 solder is composed of lamellar ζ-Au5Sn and δ-AuSn phases after preparing and the melting point approximates to the eutectic temperature of Au-20Sn alloy. A eutectic ζ-Au5Sn+δ-AuSn microstructure forms in the solder matrix and hexagon (Ni,Au)3Sn2 intermetallics nuclear at the as-reflowed joint. Then the AuSn20/Ni joint was aged at 150 and 200 °C for various times，and the thickness of the IMC layer at 150 °C changes few with the aging time increasing from 150 h to 1000 h, however, it grows rapidly at 200 °C.

Abstract: Friction Stir welding has been attempted to study the feasibility of FSW between aluminium sheet (AA 6061) of 2 mm thick and Zinc coated steel (HIF-GA) sheet of 1 mm thick in lap joint configuration. The interfacial area of dissimilar welds has been analyzed by XRD, EPMA,TEM with EDS and nano indentation technique to identify the IMC distribution pattern depending on the combined effect of rotational speed and travel speed as well as the effect of energy and thermal cycle. The average joint strength is significantly influenced by the thermal cycle, respective torque and combined effect of rotational speed and travel speed as well as energy input. Improved joint strength between Al and coated steel could be obtained within a combination of rotational speed and travel speed as well as energy input. Force and torque response during FSW have been analyzed in terms of parameter optimization and joint performance.

Abstract: In this study, effects of welding time and elements Mg, Si and Cu in aluminum alloys on hardness and tensile shear strength of aluminum alloys/steel joints in resistance spot welding have been investigated. The welding current was kept a constant 10.5kA and electrode force was 1kN. Welding time was increased from 0.067s up to 0.2s with a rise of 0.033s. Two intermetallic compound layers were generated at weld interfacial zones between aluminum alloys and steel during welding process, and the major phases were FeAl3 adjacent and directing to aluminum alloy and Fe2Al5 adjacent and directing to the steel. Diffusion of Si in aluminum alloy occurred at the interface, whereas the diffusion of Mg and Cu was not observed at the interface according to the EPMA analysis results. Hardness of intermetallic compound layers was 13.8GPa, which was about 12 times as much as that of the aluminum alloy. The largest tensile-shear strength was obtained on the condition of 0.134 and 0.167s welding time.

Abstract: A pilot polycrystalline magnetization study of Tb₂Pd₂In in comparison with new single-crystal data reveal interesting magnetocrystalline anisotropy with field induced spin-flip transitions both in the c- and a-axis of the tetragonal structure.

Abstract: Zr-based AB₂-Laves phase type alloys containing the same type of A and B metals, have been prepared from pure elements by melting and subsequent re-melting under argon atmosphere by using a HF-induction levitation furnace. Characterization of the alloys has resulted from powder X-Ray Diffraction (XRD) measurements and SEM/EDX analyses. Systematic PCI (Pressure-Composition-Isotherms) measurements have been recorded at 20 and 90 °C, using a high-pressure Sievert's type apparatus. The purpose of this study is to find a series of alloys promptly forming metal hydrides (MH) with suitable properties in order to build a MH-based hydrogen compressor, working in the same way between 20 and ~100 °C.

Abstract: In the present work at the first time the hydrogen interaction with Ce₆Ni_1.67Si₃ at pressure up to 45 atm and temperature 51_˚C has been investigated by means of the calorimetric method. The ΔHabs. – C dependence (ΔHabs. –the partial molar enthalpy of the reaction of the hydrogen interaction with IMC, C – hydrogen concentration, C=H/IMC) was obtained.

Abstract: The research status of welding process between magnesium with steel have been surveyed．This article detailed the laser welding, Laser-TIG hybrid welding, pressure welding,diffusion brazing. The paper pointed out that it is a prominent problem of magnesium to be oxidated easily and existing intermetallic compound in the joint, which will produce adverse effect to property of welded joint. So how to control morphology and existence state of intermetallic compound (IMC) is the key for quality connectors in joining of magnesium with steel.

Abstract: Al/SiC composites are used especially in automotive and aerospace industry due to the numerous advantageous mechanical properties. These end-products can be produced by casting or powder metallurgical techniques. High strength with high toughness can be reached only by perfect interfacial bonds between the matrix and reinforcing phase. To improve the interfacial bond, one of the methods is the surface coating of the SiC particles. But the metal layer of the reinforcing phase reacts with the matrix due to the high sintering temperature and long sintering time. In our research work the formation of Al-Ni intermetallic phase was investigated by Scanning electron microscopy (SEM) and X-ray diffraction measurements (XRD).

Abstract: The microstructure of the commonly used SnAgCu (SAC) lead free solder alloy was investigated. SAC solder bumps were soldered by two different soldering techniques (Vapor Phase Soldering (VPS), Laser reflow). Since the soldering profile of the VPS method is considerably different from the temperature profile of the laser reflow soldering, the created microstructures are expected to be diverse. Selective electrochemical etching was applied on cross sectional samples in order to extract the tin from the cross sectioning plane. In this manner the spatial structure of Cu₆Sn₅ and the Ag₃Sn intermetllic compounds (IMCs) was highlighted. The microstructures of the samples were analyzed with optical microscopy and Scanning Electron Microscope (SEM) on cross-section samples. The composing elements were identified by SEM-EDS.

Abstract: The structural, electronic and magnetic properties of ThCr2Si2-type compounds ARu2Sb2 (A=Sr, Ba) with space group I4/mmm (139) were studied by means of Full Potential – Linearized Augmented Plane Wave Method (FP-LAPW) method by using WIEN2K code. The necessary input parameters to perform the ab-initio calculation for ARu2Sb2 (A=Sr, Ba) are taken from ARu2As2 (A=Sr, Ba). To our knowledge the properties of these compounds have not been investigated before. From this work the optimized structural parameters, bulk modulus, electronic specific heat coefficient, Fermi energy, Magnetic moment are obtained and for ARu2Sb2 (A=Sr, Ba). Density of States histograms and Electron density plots are also plotted to analyze the bonding nature between the atoms in these compounds.