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

Dejan Gurešić,Milica Tomović,Nadežda Talijan,Vladan Ćosović,Aleksandar Đorđević,Dušan Milisavljević

doi:10.30544/211

Abstract

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.

Highlights

It is well known that Cu and Cu based alloys are very important for electronic industry
The selection of temperature for the isothermal section i.e. for the study of alloy samples was based on analysis of the predicted phase diagrams of three binary subsystems belong to three-phase region (Bi)-Ga [13], Bi-Cu [14] and Cu-Ga [15], that are presented on Fig. 1
Thirty alloy samples from the isothermal section at 100 oC were prepared for investigation, from which 27 are ternary alloys and three are binary alloys

Summary

Introduction

It is well known that Cu and Cu based alloys are very important for electronic industry. The selection of temperature for the isothermal section i.e. for the study of alloy samples was based on analysis of the predicted phase diagrams of three binary subsystems Bi-Ga [13], Bi-Cu [14] and Cu-Ga [15], that are presented on Fig. 1. The second binary subsystem Bi-Cu [14] (Fig. 1b) is eutectic system with eutectic reaction at 270.5 oC while the (Bi)+(Cu) phase region is stable from 0 up to eutectic temperature. The prepared alloys from the selected isothermal section were characterized in terms of microstructure, chemical and phase composition, Brinell and Vickers hardness and electrical conductivity. Homogeneity and composition off the prepared alloy samples were checked by EDS elemental mapping.

Results and discussion

70.77 Ga CuGa2

Conclusion