Effect of the build orientation on mechanical and electrical properties of pure Cu fabricated by E-PBF

TL;DR

This study demonstrates that Electron Beam Powder Bed Fusion can produce dense, high-conductivity pure copper components with properties comparable to conventional methods, regardless of build orientation, by optimizing process parameters.

Contribution

It provides an optimized E-PBF process for pure copper that achieves high density and electrical/mechanical performance independent of build orientation.

Findings

Achieved >99.9% density in E-PBF copper samples.

Electrical and mechanical properties match conventional copper.

Properties are consistent across different build orientations.

Abstract

Electrical conductors are usually made of pure copper because this material shows outstanding electrical conductivity (IACS > 100%). Additive manufacturing can be used to further improve the performances of such electrical conductors because it enables to consider sophisticated geometries impossible to be fabricated by conventional processing routes such as casting, machining or hot forming. In the present work, Electron Beam Powder Bed Fusion is optimized to achieve dense pure copper specimens (relative density >99.9%). Only few residual spherical pores inherited from the as-received powder particles are detected in the samples as nicely revealed by X-ray microtomography scans. Three different build orientations, namely 0{\textdegree}, 45{\textdegree} and 90{\textdegree} with respect to the build direction are produced. The microstructures are characterized using optical microscopy and EBSD measurements. The electrical conductivity is measured using the Eddy current method as well as the four-probes method while the mechanical properties are assessed using Vickers microhardness and tensile mechanical testing. The electrical and mechanical performances are discussed in the light of the microstructural characterizations, and further compared with a cold-worked Cu-ETP sheet subjected to an annealing treatment. It demonstrates that E-PBF is able to reliably produce components made of pure Copper whose properties equal those of pure copper fabricated by more conventional processing routes, regardless of the build orientation.