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Characterization Of Materials Properties In Additively Manufactured Aisi-420 Martensitic Steel Deposited By Laser Engineered Net Shaping, Md Mehadi Hassan

Nanoscience and Microsystems ETDs

Metal additive manufacturing (AM) is a disruptive technology enabling the fabrication of complex and near-net-shaped parts by adding material layer-wise. It offers reduced lead production time. AM processes are finding applications in many industrial sectors such as aerospace, automotive, biomedical, and mold tooling. Despite the tremendous advantages of AM, some challenges still prevent this technology's adoption in high-standard applications. Anisotropy and inhomogeneity in the mechanical properties of the as-built parts and the existence of pores and lack-of-fusion defects are considered the main issues in directed energy deposition (L-DED) parts. Laser-engineered net shaping LENS® offers excellent possibilities to fabricate metal tools …

Investigating The Classical And Non-Classical Mechanical Properties Of Gan Nanowires, Mohammad Reza Zamani Kouhpanji

Electrical and Computer Engineering ETDs

Study and prediction of classical and non-classical mechanical properties of GaN is crucial due to the potential application of GaN nanowires (NWs) in piezoelectric, probe-based nanometrology, and nanolithography areas. GaN is mainly grown on sapphire substrates whose lattice constant and thermal expansion coefficient are significantly different from GaN. These discrepancies cause mechanical defects and high residual stresses and strains in GaN, which reduce its quantum efficiency.

Specifically, for nanoscale applications, the mechanical properties of materials differ significantly compared to the bulk properties due to size-effects. Therefore, it is essential to investigate the mechanical properties of GaN NWs using the non-classical …

High-Throughput Tensile Testing Reveals Stochastic Properties In Additively Manufactured Steel, Bradley C. Salzbrenner

Mechanical Engineering ETDs

An adage within the Additive Manufacturing (AM) community is that “complexity is free”. Complicated geometric features that normally drive manufacturing cost and limit design options are not typically problematic in AM. While geometric complexity is usually viewed from the perspective of part design, this advantage of AM also opens up new options in rapid, efficient material property evaluation and qualification. This Thesis demonstrates how 100’s of miniature tensile bars can be produced and tested for comparable cost and in comparable time to a few conventional tensile bars. With this technique, it is possible to evaluate the stochastic nature of mechanical …