Reversible “Wetting” of grain boundaries by the second solid phase in the Cu-In system

Bulk and Surface Low Temperature Phase Transitions in the Mg-Alloy EZ33A

“…As the microstructure after such long annealing times is close to equilibrium, the difference to the fraction of covered GBs in the first sample confirms the existence of the solid phase GB wetting transition in EZ33A. Similar phenomenon of GBs completely and/or incompletely covered with layers of a second solid phase have been observed also in Al- [11,12], Cu- [13,14], Co- [15], Fe- [16], Zr- [17], and Ti-based alloys [18,19]. Thermodynamically, this phenomenon is very similar to the GB wetting by the melt [20,21].…”

Non-equilibrium Grain Boundary Wetting in Cu–Ag Alloys Containing W Nanoparticles

“…[14,15] Far more common are GB complexions, [16,17] but in the present work, the Ag is clearly forming a wetting layer and not a complexion, that is, the thick Ag layer is an equilibrium bulk phase and not an equilibrium GB phase. The lack of GB wetting layers in most metals is not surprising since close to equilibrium, a wetting layer requires the interface energy to be less than half of the GB energy of the matrix.…”

“…We show that this wetting layer, in fact, is a non-equilibrium structure that results from the constraints imposed on the Ag precipitates by the W nanoparticles. The alloy specimens employed in the experiments, Cu 83.5 Ag 15 W 1.5 and Cu 85 Ag 15 , were prepared by physical vapor deposition growth on oxidized Si wafers at room temperature using DC magnetron sputtering. Film thicknesses were ≈ 300 nm, with a 2-3 nm W capping layer on the surface to prevent Ag segregation during annealing.…”

Investigation of Cu particles size and bonding time on the microstructure and shear property of Cu/In-45Cu/Cu solder joints

“…Cu 2 In phase is formed on the surface of Cu particles, which causes the thermodynamic non-equilibrium state of the initially formed Cu 11 In 9 compound and Cu particles. Cu 11 In 9 phase sheds from the surface of Cu particles, providing the growth space of the Cu 2 In equilibrium phase [35,36]. Figure 7 reveals the relationship between shear strength of Cu/In-45Cu/Cu solder joints and different bonding time.…”