REACTION OF NANOCRYSTALLINE MECHANICALLY ALLOYED CU-SN ALLOY WITH GA-IN-SN EUTECTIC

An extended solid solution of Cu-20wt%Sn with lattice parameter 0.3715 nm and grain sizes 7 nm, was obtained by mechanical alloying. A DSC t race of Cu-20wt%Sn showed an exothermic effect at 643 K due to the cry stalline grain growth and the formation of an equilibrium solid soluti on. The reaction of Cu-20wt%Sn with a Ga-In-Sn liquid alloy was studie d at room temperature by measuring peak intensities of CuGa2, the inte rmetallic compound formed during the reaction, as a function of time. The reaction rate increased when crystalline grain size D decreased. M echanical alloying process used to control the reactivity of nanocryst alline solid solutions as components in low temperature solder pastes.