Effects of different solidification modes,including of furnace cooling,air cooling,water cooling and liquid nitrogen cooling,and magnetic fields on the impact toughness and microstructure of Sn-Bi solders are studied.The results show that fast cooling and rotating magnetic fields were applied for refining the structure of the Sn-Bi solder.Although these technologies can refine the grain size,meanwhile they reduced the plasticity of the solder.For Sn-57Bi alloy fast cooling caused the segregation of Bi,and t...