Characterization of copper & stainless steel interface produced by electron beam powder bed fusion

Unalloyed copper (Cu) powder was deposited and melted onto a pre-existing stainless steel substrate using electron beam powder bed fusion (EB-PBF) additive manufacturing (AM) to form dense, bimetallic structures. The AM fabricated Cu was fully dense, and with strength properties consistent with recent reports on EB-PBF of Cu. The overall bimetallic structures exhibited total elongation of 25-35%, and was dominated by plastic deformation in the Cu region. Tensile failures were typically observed in the Cu portion of the bimetallic bodies demonstrating that the interface was not the source of mechanical failure. The interface region of the bimetallics contained areas of liquid phase separated Cu and Iron (Fe) + Chromium (Cr) rich regions resulting from a metastable miscibility gap in the Cu and Fe phase diagram. Metallurgical and mechanical examinations of the bimetallic structures showed the interface region transitions from an Fe rich mixture to a Cu rich mixture within a few AM layers. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Copper powder was deposited onto stainless steel substrate using electron beam powder bed fusion additive manufacturing to create bimetallic structures with consistent strength properties. The interface region of the bimetallic structures contained liquid phase separated copper and iron + chromium rich regions, transitioning from an iron rich mixture to a copper rich mixture within a few additive manufacturing layers.