Abstract: A droplet comprises a core including an alloy comprising a majority of a first metallic element and a minority of a second element, wherein the core is in a liquid state below a solidus temperature of the alloy. A shell is arranged to enclose the core and includes an exterior surface comprising a majority of the second element and a minority of the first metallic element, wherein the shell is in a solid state below the solidus temperature of the alloy. The alloy can comprise a solder material that can be used to form solder connections below a solidus temperature of the alloy.