The Microstructure and Mechanical Properties of Sn-58Bi Eutectic Alloy Wires

The Sn-58Bi eutectic alloy wires with different diameter were manufactured successfully in this paper. In comparison with poured Sn-58Bi eutectic alloy, the mechanical properties were tested by an universal mechanical testing machine (MTS T4204), the deformation behavior of Sn-58Bi alloy wires at different diameters were investigated by observing the fracture surface structure and microstructures were observed by the Scanning electron microscope (Sigma Zeiss). The results show that the bismuth grains in the wires became discontinuous compared with poured Sn-58Bi eutectic alloy, and the fracture mode of poured Sn-58Bi alloy was brittle cleavage fracture and the fracture elongation was low; fracture mode of Sn-58Bi alloy wires was cleavage fracture and ductile trans-granular fracture and the fracture elongation was very high. Analysis suggests that above phenomenon related with the microstructure of Sn-58Bi alloy, the grains were refined after processed and the fine bismuth grains could coordination with the deformation of the matrix tin, the micro-porous cracks were delayed by increased grain boundaries quantities, so the fracture elongation of Sn-58Bi alloy wires was very good.