Author ORCID Identifier

https://orcid.org/0009-0009-0200-931X

Semester

Summer

Date of Graduation

2024

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Committee Chair

Bruce Kang

Committee Co-Chair

Terence Musho

Committee Member

Terence Musho

Committee Member

Zhichao Lui

Committee Member

Kostas Sierros

Abstract

Additive Manufacturing (AM) has become popular for commercial applications where high-performance parts can now be created, tested, and modified more efficiently thus expediting the design process. Because of its relatively easy access today a lot of research and improvements are coming out yearly for improved AM machines and the material used. At WVU, a new way of modifying as-receive commercial gas-atomized metal powders used in AM has been developed using Mechanical Chemical Bonding (MCB) methodology which uses high rotational blades to create an environment where it increases the particle-on-particle interaction. During this high energetic process all irregular shaped particles, with satellite surface agglomeration, were shaped to near spherical geometry, while the internal gas pores are also eliminated, thus obtained denser particles. Packing density and flowability of the particles before and after MCB processing were carried out by a PTG-S5 flowmeter machine. Stainless Steel 316 and Inconel 718 powders were used in this research in the size ranges of 15-53 µm and 45-106 µm. Results showed that both the packing density and flowability increased by about 30%. Thus, this new MCB-processing method can make the powders with higher density, narrower size range, smoother surface morphology, and better flowability and packaging density; therefore, produce better structural parts (i.e. less internal defects and stronger mechanical properties) by AM.

Furthermore, the MCB technique was also found as a very efficient method of coating minor addition of strengthening phases to the as-received gas atomized powders. Using MCB method, Oxide Dispersion-Strengthened (ODS) IN718 powders, i.e. uniform coating of various wt% Yttria on all surfaces of the 718 powders have been successfully fabricated. Preliminary tensile testing of AM-printed ODS IN718 alloys at 1050 C showed almost double the tensile strength comparted to the AM-printed IN718.

Lastly, the MCB method also appears to be a very effective method of recycling used AM’ed powders. Various post printed powders show concerning characteristics of damaged and irregular shaped powders due to laser power sintering during printing. After MCB re-processing the leftover AM’ed powders results show cleaned up powder with many of troubling powder properties being negated. Flowability and packing density of these MCB recycled powders also show improvements in these areas, which provide potential pathway for applications to downstream industries, such that sustainability and significantly reduce carbon footprint can be realized.

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