Date of Award
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Mechanical Engineering
Committee Chair
George J. Nelson
Committee Member
Babak Shotorban
Committee Member
Gang Wang
Committee Member
Jason R. Mayeur
Research Advisor
Kavan Hazeli
Subject(s)
Copper alloys--Mechanical properties, Structural analysis (Engineering), Thin-walled structures
Abstract
This study investigates size effects on microstructure, mechanical behavior, and fatigue performance of additively manufactured GRCop-42. Systematic analyses, encompassing changes on powder composition, wall thickness, and heat treatment, was conducted on specimens produced through laser powder bed fusion (L-PBF) and laser powder direct energy deposition (DED) techniques. L-PBF specimens exhibited a reduction in strength and elongation with decreasing thickness, attributed to increasing porosity as specimen’s thickness decreases. Conversely, in DED specimens, decreasing mechanical properties with thickness were associated to surface topography. Emphasizing the non-generalizability of size effects across AM methods. Size effects were also investigated on high cycle fatigue, as tensile properties cannot be readily translated into fatigue properties. Fatigue testing of L-PBF specimens revealed internal defects as operative features responsible for an early fatigue failure, which were remediated by hot isostatic pressing. Fractography unveiled size-dependent fatigue characteristics, particularly an increased presence of brittle features on thinner specimens. This investigation highlights the significance of size effect considerations for GRCop-42 in AM applications.
Recommended Citation
Demeneghi, Gabriel, "Characterization of size effects in additively manufactured GRCop-42 and their influence on mechanical response" (2024). Dissertations. 400.
https://louis.uah.edu/uah-dissertations/400