Novel precipitate-microstructural architecture developed in the fabrication of solid copper components by additive manufacturing using electron beam melting

The fabrication of Cu components by additive manufacturing using electron beam melting (EBM) from low-purity, atomized Cu powder containing a high density of Cu(2)O precipitates exhibits a novel example of precipitate dislocation architecture. Such architectures are seen by optical metallography, and scanning and transmission electron microscopy, to consist generally of equiaxed precipitate dislocation cell-like arrays (1-3 mu m) in the horizontal reference plane perpendicular to the build direction with elongated or columnar-like arrays extending from similar to 12 to >60 mu m in length and corresponding spatial dimensions of 1-3 mu m. The hardnesses for these architectures ranged from similar to HV 83 to 88, in contrast to the original Cu powder microindentation hardness of HV 72 and the commercial Cu base plate hardness of HV 57. These observations illustrate the prospect for creating some form of controlled microstructural architecture by EBM parameter alternation or optimization. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.