Effect of graphene nanoplates on microstructure and properties of Sn-58Bi solders

In the present work, Sn-58Bi composite solders with different amount of graphene nanoplates (GNSs) have been prepared by powder metallurgy method. The melting point of the solder was slightly affected by the addition of few amount of GNSs. With the increase of the amount of GNPs, the density and vickers microhardness were firstly increased to the peak value and then decreased with further addition of GNSs. It has been found that the brazed joint of Sn-58Bi/Cu substrate could be significantly improved by the addition of GNSs. The improvement should be attributed to the grain refinement and the dispersion strengthening effect of GNSs.