Date of Award

Summer 8-2-2024

Degree Type

Thesis

Degree Name

Master of Science in General Engineering

First Advisor

Nathan Huft

Second Advisor

Peter Lucon

Third Advisor

Sudhakar Vadiraja

Abstract

The design of new alloys specifically for metal additive manufacturing (AM) is an emerging field of research. At present, metal AM primarily utilizes pre-alloyed powders, which are costly and lack flexibility in varying chemical compositions. This study outlines the adaptation of rapid alloy development in laser powder bed fusion (L-PBF) using elemental and ferro-alloyed powder blends. This method enables a more agile and resource-efficient approach to designing and screening new alloys, allowing for the swift generation of alloys with diverse chemical compositions. This thesis investigates the development of AF96 steel alloy through the innovative approach of mixing different elemental powders, utilizing Dry Metal Alloying (DMA) as the primary technique. Dry Metal Alloying uses multiple elemental and ferro-alloyed powders with a known composition mixed in proportion to achieve a desired bulk composition. The study employed a Resonant Acoustic Mixer (LabRAM II) to blend six distinct powder combinations to form the AF96 steel alloy. Notably, AF96 steel alloy has not been extensively explored for use in laser powder bed fusion (L-PBF), despite its potential benefits in enhancing the properties and performance of additively manufactured components. This research underscores the importance of exploring AF96 steel in L-PBF due to its promising applications in producing high-strength, high performance, low cost, and wear-resistant parts. The study meticulously examined the influence of various processing parameters and the resultant linear energy density input on the homogeneity of the manufactured parts. Comprehensive characterization of the powders and deposits was conducted using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Fluorescence (XRF), and Arc Spark Optical Emission Spectroscopy (OES). These techniques provided detailed insights into the elemental distribution, and chemical composition of the alloy. Furthermore, the mechanical properties of the DMA deposits were rigorously evaluated to assess their suitability for practical applications. The findings of this research contribute significantly to the understanding of alloy development via elemental and ferro-alloyed powder mixing specifically Dry Metal Alloying and highlight the potential of AF96 steel alloy in advancing the capabilities of metal additive manufacturing.

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