Effect of chemical composition on microstructure, hardness and electrical conductivity profiles of the Bi-Cu-Ga alloys at 100 °C

Theoretical calculation and experimental investigation of the isothermal section of a ternary Bi-Cu-Ga system at 100 oC are presented in this paper. Thermodynamic binary-based calculation of the isothermal section was performed using Pandat software. Experimental investigation included microstructural analysis carried out using light optical microscopy (LOM) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), phase composition analysis using X-ray diffraction (XRD), Brinell and Vickers hardness testing and electrical conductivity measurements. In total, thirty alloy samples with compositions along three vertical sections Bi-CuGa, Cu-BiGa and Ga-BiCu were studied. The obtained experimental results support the calculated phase regions of the isothermal section at 100 oC. Hardness of individual phases as well as hardness and electrical conductivity of the studied alloys were measured. Based on the experimentally obtained results iso-lines of Brinell hardness and electrical conductivity along the whole compositional range were calculated by using appropriate mathematical models