Characterization of liquid-phase sintered materials produced from mechanically alloyed Cu + Sn powder compacts

• Mechanical alloying produced multilayered Cu/Sn powders.
• Multilayered Cu/Sn powders enhanced wettability of liquid Sn on solid Cu.
• Independent nucleation and growth of Cu6Sn5 grains from a melt
• Amorphous Cu–Sn layer formed between the Cu and Cu6Sn5 layers.

Mechanical alloying was employed to produce multilayered Cu/Sn particles with cold welded Cu/Sn interfaces capable to enhance wettability of liquid Sn on solid Cu during liquid-phase sintering. Independent nucleation and growth of Cu6Sn5 grains in the melt resulting in the formation of the Cu6Sn5 intermetallic layer upon grain impingement were observed in the liquid-phase sintered specimens. Amorphous Cu–Sn layer was formed between the Cu and Cu6Sn5 layers. Formation of this phase cannot be explained by the interfacial reactions normally occurring in soldering of Sn-base solders on a Cu substrate but the amorphous layer is inherited from the amorphization during mechanical alloying.