Date of Award
Master of Science
Metallurgical and Materials Engineering
This research study presents experimental examples of as-built microstructures and associated microindentation hardnesses (HV) for a variety of metal additive manufacturing (AM) methods for Inconel 625 alloy. Cold spray (CS), laser powder bed fusion (L-PBF), wire arc additive manufacturing (WAAM), electron beam directed energy deposition (EB-DED), laser hot wire (LHW), binder jetting (BJT), and laser power directed energy deposition (LP-DED), laser wire directed energy deposition (LW-DED) and electron beam melting (EBM) were among the techniques employed. Microstructures varied from impact-bonded, flattened grains containing microdendrites and dislocations with a microindentation hardness of HV 590 for cold spray to large, equiaxed grains with a microindentation hardness of HV 180 for binder jet-printed components. Various widths of columnar grains with parallel and cellular arrays of microdendrites were generated via electron and laser beam melt-related methods, including wire and powder feeds, with microindentation hardnesses ranging from HV 304 to HV 228. Subsequently, different heat treatments including stress relief, stress relief + homogenization, stress relief + homogenization + solutionizing, stress relief + hipping + solutionizing were applied to all manufactured components. The microstructural evolution through each heat treatment is reported along with their respective microhardness values. These findings show variances in microstructure resulting from several AM methods in both as built and heat-treated states, as well as considerations for utilization in end-use applications.
Received from ProQuest
Gamon, Ariel, "Microstructure And Hardness Comparison Of Inconel 625 Alloy Of Various Additive Manufacturing Processes Following Heat Treatments" (2021). Open Access Theses & Dissertations. 3410.