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Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced By Electron Beam Freeform FabricationThe electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties have been demonstrated for electron beam deposited aluminum and titanium alloys that are comparable to wrought products, although the microstructures of the deposits exhibit features more typical of cast material. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. In the current study, mechanical properties and resulting microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Material performance was evaluated based on tensile properties and results were compared with properties of Al 2219 wrought products. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains, typically with interior dendritic structures, which were described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.
Document ID
20080014081
Document Type
Conference Paper
Authors
Domack, Marcia S. (NASA Langley Research Center Hampton, VA, United States)
Taminger, Karen M. B. (NASA Langley Research Center Hampton, VA, United States)
Begley, Matthew (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 24, 2013
Publication Date
July 9, 2006
Subject Category
Metals and Metallic Materials
Meeting Information
10th International Conference on Aluminum Alloys - ICAA-10(Vancouver)
Funding Number(s)
WBS: WBS 23-064-50-10
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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