Copper alloys with improved properties: standard ingot metallurgy vs. powder metallurgy

Milan T Jovanović,Ivana Cvijović-Alagić,Višeslava Rajković

doi:10.5937/metmateng1403207j

Abstract

Three copper-based alloys: two composites reinforced with Al2O3 particles and processed through powder metallurgy (P/M) route, i.e. by internal oxidation (Cu-2.5Al composite) and by mechanical alloying (Cu-4.7Al2O3 ) and Cu-0.4Cr-0.08Zr alloy produced by ingot metallurgy (vacuum melting and casting) were the object of this investigation. Light microscope and scanning electron microscope (SEM) equipped with electron X-ray spectrometer (EDS) were used for microstructural characterization. Microhardness and electrical conductivity were also measured. Compared to composite materials, Cu-0.4Cr-0.08Zr alloy possesses highest electrical conductivity in the range from 20 to 800 ℃, whereas the lowest conductivity shows composite Cu-2.5Al processed by internal oxidation. In spite to somewhat lower electrical conductivity (probably due to inadequate density), Cu-2.5Al composite exhibits thermal stability enabling its application at much higher temperatures than materials processed by mechanical alloying or by vacuum melting and casting.

Highlights

Age hardened copper alloys such as Cu–Cr, Cu–Zr and Cu–Cr–Zr obtain high strength and hardness through the precipitation of tiny coherent particles from a supersaturated copper matrix [1]
Previous works has proved that addition of hard particles such as SiC, Al2O3, TiB2 and TiC [2,3,4] can significantly improve the mechanical properties of copper matrix materials while maintaining high electrical and thermal conductivity
The uniform distribution of Al2O3 particles can be accomplished by the process of internal oxidation [8, 9] or by mechanical alloying [10, 11]

Summary

Introduction

Age hardened copper alloys such as Cu–Cr, Cu–Zr and Cu–Cr–Zr obtain high strength and hardness through the precipitation of tiny coherent particles from a supersaturated copper matrix [1]. Previous works has proved that addition of hard particles such as SiC, Al2O3, TiB2 and TiC [2,3,4] can significantly improve the mechanical properties of copper matrix materials while maintaining high electrical and thermal conductivity.

Results

Conclusion