Effects of impurities on double twinning nucleation and grain refinement of Sn-based solder joints

摘要: As-solidified Sn3.0Ag0.5Cu + 3.0POSS (polyhedral oligomeric silsesquioxanes), Sn3.0Ag0.5Cu + 0.05CNTs (carbon nanotubes) and Sn3.0Ag3.0Bi3.0In (SABI333) solder joint orientations were quantitatively characterized by electron backscatter diffraction observations. Unlike the typical Sn-based joints in which single grains, tricrystals or double are normally observed, for studied joints, frequency of single-grained was greatly reduced, SABI333 typically consisted polycrystals. If Sn dendrites deviated more than 15° from preferred [110] $$[1{\bar{1}}0]$$ directions, then these polycrystals solidified Sn–Ag-based melt. Moreover, Bi In atoms alloys could significantly change directions. addition, two types twinning tin observed during reflow Pb-free joints. Different morphologies between twinned microstructures. However, misorientations groups ranged 80° to 90°. one systems, four grain had same twin with a common [100] [010] direction; other system, perpendicular each other.