New solder compositions having enhanced mechanical properties are disclosed. Relatively inert particles having a diameter of 2000 nm or less are dispersed in a solder material having an average grain size of 500 nm or less to produce such solder compositions. The dispersed particles act as physical barriers substantially impeding the motion of grain boundaries and inhibiting grain growth during thermal and stress cycling which substantially inhibits coarsening. As a consequence, the solder composition exhibits an advantageous level of superplasticity that is substantially resistant to joint failure. Methods for forming articles using such solder compositions is also disclosed.