Y. Yu

Hexagonal-Rod Growth Mechanism and Kinetics of the Primary Cu6Sn5 Phase in Liquid Sn-Based Solder

A hexagonal-rod growth mechanism is proposed to describe the growth behavior of the primary Cu6Sn5 phase in liquid Sn-based solder. After Sn-6.5xa0at.%Cu solder had been maintained at 250°C for 10xa0h, a large number of hexagonal-rod-type Cu6Sn5 grains were found to have separated within it. Our observations show that these hexagonal rods had side facets in the

Effect of blue tungsten oxide on skeleton sintering and infiltration of W-Cu composites

{ 10overline{1} 0}_{mathrm{eta} }

Experimental Investigation and Thermodynamic Calculation of the Phase Equilibria in the Al-Bi-Sn Ternary System

{101¯0}η family and round ends close to the {0002}η family. Moreover, the nucleation of the hexagonal rods was studied, and the corresponding growth kinetics found to be governed by a Cu-supply-controlled mechanism rather than an interfacial-reaction-controlled or Cu-diffusion-limited mechanism. More importantly, the anisotropic growth of the Cu6Sn5 phase was confirmed to be the dominant reason for production of these primary hexagonal rods with high aspect ratio. This may represent an avenue for synthesis of nanosized Cu6Sn5 single crystals for use as anode materials in lithium-ion batteries. Additionally, our Cu6Sn5 hexagonal-rod growth mechanism may provide insight into morphological and kinetic studies on interfacial Cu6Sn5 grains and similar intermetallics.

Three-dimensional placement rules of Cu6Sn5 textures formed on the (111)Cu and (001)Cu surfaces using electron backscattered diffraction

The microstructural evolution in eutectic Sn-37Pb solder under high current density seriously threatens the reliability of solder interconnections, but atomic electromigration has often been confused with thermomigration. In this paper, after decoupling the effect of the non-uniform temperature distribution in a Cu/Sn-37Pb/Cu lap joint from the current stress, the microstructural evolution was investigated under an average current density of 1.84xa0×xa0104xa0Axa0cm−2 for 0–24xa0h. The decomposition and recombination of the Pb-rich phase occurred at the cathode and the anode, respectively. The corresponding migration mechanism was proposed from the viewpoint of energy and was explained by the interactions among the potential energies of ripening, electron wind force, and back stress. Our study may be helpful for understanding the migration mechanism and reliability of eutectic two-phase solder joints and provides supporting data for interpreting the acceleration tests of Sn-37Pb solder joints under electromigration.