Date of Award
2026
Document Type
Open Access Master's Thesis
Degree Name
Master of Science in Materials Science and Engineering (MS)
Administrative Home Department
Department of Materials Science and Engineering
Advisor 1
Sriram Vijayan
Committee Member 1
Walter Milligan
Committee Member 2
Yongmei Jin
Committee Member 3
Steven Kampe
Committee Member 4
Daniel Segiun
Abstract
Laser Powder Bed Fusion (LPBF) enables fabrication of metallic parts with intricate geometries, low ‘buy to fly’ ratio, and reduced tooling in small batches. The non equilibrium nature of the LPBF process results in steep thermal gradients, rapid solidification and rapidly fluctuating thermal cycles that promote the formation of high-temperature metastable phases, including δ-ferrite and austenite in alloys like 17-4 Precipitation Hardened (PH) Stainless Steel, which typically consists of a martensitic microstructure in the cast and wrought form. These metastable microstructures formed in 17-4PH SS LPBF parts result in mechanical properties that are vastly different from their conventional processed counterparts, presenting a major barrier to industrial adoption. These challenges reveal a major gap in our understanding of the physical metallurgy of LPBF parts. Therefore, a thorough and systematic assessment of process-structure-property relationships is required, to ensure consistent microstructural control, predictable mechanical performance, and reliable components qualification. In this thesis, the microstructural stability, phase evolution, and mechanical properties of LPBF built 17-4PH SS were systematically investigated as a function of build arrangement, powder feedstock characteristics and laser scan strategies.
Recommended Citation
Bollu, Gowri Shankar, "PROCESS-STRUCTURE-PROPERTY ANALYSIS OF LASER POWDER BED FUSION 17-4PH STAINLESS STEELS: EFFECTS OF BUILD ARRANGEMENTS, POWDER FEEDSTOCK VARIATIONS AND SCAN STRATEGIES", Open Access Master's Thesis, Michigan Technological University, 2026.