Date of Award


Degree Name

Master of Science


Metallurgical and Materials Engineering


Lawrence E. Murr


Unlike more conventional directional solidification, electron and laser-beam melting technologies involve building 3D components through layer-by-layer melt/solidification thermal cycling which creates novel, directional microstructural architectures. In this study we compared various the columnar microstructures of various components manufactured by EBM and SLM; image composite observations of columnar microstructural architectures in Cu, Co-29-Cr-6Mo-0.2C alloy, Ni-22Cr-9Mo-4Nb (alloy 625) fabricated by electron beam melting (EBM), and Ni-19Cr-19Fe-5Nb-1Al (alloy 718) by selective laser melting (SLM) as well as stainless steel 17-4 PH (SLM). Cu produced discontinuous columns of Cu2O precipitates while the Co-base alloy exhibited similar columns of Cr23C6 precipitates. The alloy 625 produced columns of Ni3Nb (ϒ"-bct) precipitates. All of the EBM-produced columnar microstructure arrays were spaced ~2 μm. In contrast, the SLM fabricated alloy 718 contained columnar microstructural arrays of Ni3Nb (ϒ") spaced ~ 0.8μm, the 17-4 PH stainless steel produced martensitic structures dependent on the gas used for manufacturing. The manufactured components were observed by optical microscopy, SEM, XRD and by TEM in order to understand the microstructural development.




Received from ProQuest

File Size

105 pages

File Format


Rights Holder

Edwin Martinez

Included in

Engineering Commons