Effect of the Elemental Content of Bi and Pb on the Properties of Sn-Bi-Pb Low Melting Point Alloys

Abstract

Using the tin alloy module in the material phase diagram and thermodynamic simulation software JMatPro, the phase compositions of different components of Sn-Bi-Pb low melting point alloys with the same Sn content were simulated based on the phase diagrams of Sn-Bi, Sn-Pb, and Pb-Bi binary alloys, and the influence of alloying element content on the melting characteristics of the alloys was investigated, which was used for the optimization of the components and the obtaining of low melting point alloys with excellent melting characteristics. The microstructure and melting characteristics of the optimized alloys were characterized by Scanning electron microscope (SEM), Thermogravimetry Analysis-Differential Scanning Calorimetry (TG-DSC), X-ray diffractometer (XRD), etc., and the influence of phase content on the mechanical properties was investigated. The results show that the Sn-Bi-Pb alloy possesses Sn-(Bi, Pb) phase, Bi-(Pb) phase and Pb₇Bi₃ intermetallic compound phase, and the simultaneous increase of the Bi element and decrease of the Pb element content to the Sn-Bi-Pb alloy obviously improves its tensile strength, but the elongation rate shows a decreasing trend, among which Sn50Bi30Pb has the optimal comprehensive performance, with a tensile strength of 38.60 MPa, an elongation of 61.13%, and a melting range of 94.0°C∼100.6°C.