The surface structure of the liquid phase of the Au72Ge28 eutectic alloy has been measured using resonant and nonresonant x-ray reflectivity and grazing incidence x-ray diffraction. In spite of the significant differences in the surface tension of liquid Ge and Au the Gibbs adsorption enhancement of Ge concentration at the surface is minimal. This is in striking contrast to all the other binary...

Large 6 mm× 9 mm silicon chips have been successfully bonded to alumina substrates with electroplated Au/Sn/Au structure at the eutectic omposition. The new bonding process is entirely fluxless, or flux-free. It is performed in vacuum (50 milliTorrs), where the oxygen content is educed by a factor of 15,200 comparing to air, to inhibit solder oxidation. Eutectic Au80Sn20 alloy is a well establi...

CMOS compatible metallic hermetic sealing using Al-Ge eutectic alloy for packaging MEMS devices for harsh environments has been developed. The effects of various bonding parameters on the bond quality have been extensively reported. The reliability of this eutectic joint subjected to high operating temperatures involved in deep oil well logging application has been investigated with the specifi...

Al-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodyna...

The reliability of Pb-free solder joints is controlled by their microstructural constituents. Therefore, knowledge of the solder microconstituents' mechanical properties as a function of temperature is required. Sn-Ag-Cu lead-free solder alloy contains three phases: a Sn-rich phase, and the intermetallic compounds (IMCs) CueSn5 and Ag3Sn. Typically, the Sn-rich phase is surrounded by a eutectic...

As shown in the preceding chapter, simple binary eutectic Ni-Hf and Ni-Zr braze alloys can be used to successfully join In738 Ni-base superalloy. The joint gap must, however, be narrow (less than 0.15 mm in width) to allow capillary action to draw the filler metal into the joint. Such narrow joint gaps are usually only found in the manufacturing industry. In the repair industry, especially in I...

In the present study, the microstructural evolution and the modulation of the mechanical properties have been investigated for a Co-Cr-Mo (CCM) ternary eutectic alloy by addition of a small amount of copper (0.5 and 1 at.%). The microstructural observations reveal a distinct dissimilarity in the eutectic structure such as a broken lamellar structure and a well-aligned lamellar structure and an ...

Iron released by steel corrosion was found to be a key impurity in reactions with dissolved oxygen in liquid lead-bismuth eutectic alloys. The iron-oxygen-magnetite equilibrium was characterized, allowing the quantification of phenomena that are important for long-term operation of lead-alloy based installations such as corrosion rate control and management of precipitates.

the effect of t6 heat treatment on the microstructure and wear behavior of al-332 piston alloy containing 1.2wt% iron was investigated. the results showed that the t6 heat treatment changed the morphology of acicular eutectic si particles to a more spherical form. the heat treatment also reduced the average length and blunted the needle-like ?- phase intermetallics through dissolution and fragm...