Effect of Al18B4O33 whiskers on microstructure evolution of intermetallic compound layer and shear behavior of soldered joint

The effect of Al18B4O33 whiskers on the microstructure evolution of the intermetallic compound(IMC) layer on the Sn-58Bi/Cu interface was investigated, and the fracture mechanism of the Sn-58Bi-1.2% Al18B4O33 soldered joint was analyzed. The results show that, the addition of Al18B4O33 whiskers to the solder refines the solder microstructure, inhibits the formation of large pieces of Bi-rich phase. The thickness and grain size of the interfacial IMC layer are increased with the increase of the remelting cycles, but the addition of Al18B4O33 whiskers to the solder hinders the interfacial IMC layer thickening and grain coarsening, which improves the mechanical property of the brazing joint. The Sn-58Bi-1.2% A118B4O33/Cu soldered joint can bear higher shear stress than the Sn-58Bi/Cu soldered joint after multi-remelting, and its strength remains stable after multi-remelting.