A quantitative study of solute diffusion field effects on heterogeneous nucleation and the grain size of alloys

Effects of cobalt on the nucleation and grain refinement of Sn-3Ag-0.5Cu solders

“…We note that grain refinement theories stress the importance of both solute and nucleant particles [46][47][48][49]. In this case, the 0.05wt% Co addition does not significantly alter the growth restriction factor of SAC305 [50] and the increment of grain refinement is mostly due to the introduction of nucleant particles.…”

“…solder balls and joints containing CoSn 3 due to the difficulty of reliably measuring undercooling in small balls cooled at ≥ ~5K/s, but it is likely to be the case Second, the cooling rate affects the solute boundary layer in the liquid ahead of the dendrite envelope and, therefore, the growth distance required to generate sufficient constitutional supercooling (CS) to trigger another nucleation event [46,48,53]. This can be understood with reference to Figure 12(c) and (d): After the first nucleation event, the growing dendrite (or twinned dendrite) will develop a solute boundary layer and CS ahead of the dendrite envelope.…”

Numerical and Experimental Investigation of the Influence of Growth Restriction on Grain Size in Binary Cu Alloys

“…Furthermore, a saturation of grain size was observed at higher solute contents, as grain size remains rather constant above a critical alloy level. Greer et al [3] and Shu et al [27] used the experimental data provided by Spittle and Sadli [34] for comparison with their prediction models showing the correlation between grain size and Q of binary Al alloys. A similar correlation of Q and grain size in binary Mg alloys was reported by Lee et al [42].…”

“…As already mentioned, the modelling ability is limited by the fact that no commercial grain refiner with a known particle distribution was added to the melt. Furthermore, a constant diffusion coefficient was used for the alloys under investigation, and the effect of solute-suppressed nucleation, as shown by Shu et al [27], was not considered in the model. As P (Q = 27.03 K/wt % [32]) is a commonly used alloying element for deoxidation in Cu alloys, it is of interest to determine its effect on grain size.…”

“…This is also related to the lack of accessible commercial grain refiners for Cu alloys. Furthermore, a constant diffusion coefficient was used in the model and the influence of the solute diffusion zone on the nucleation potency of inoculating particles known as solute suppressed nucleation given by Shu et al [27] was neglected. calculation is limited by the fact that no master alloy with a known particle size distribution was added to the melt.…”