Wednesday  |  Phipps  |  05:00 PM–05:20 PM

#13604, Microstructure-Process-Behavior Relationship Investigation of an Additive Manufactured Aluminum Alloy using a Design of Experiments Approach

L-PBF is a metal additive manufacturing (AM) method which is being increasingly used to generate geometrically complex metallic structures. This AM method is an inherently transient and localized process involving repeated and multiple physical effects including liquid-solid thermomechanical interactions, evaporation, and rapid solidification, which they are additionally affected by feedstock material, process parameters and part geometry. Therefore, understanding the formation of the steady-state microstructures is a fundamental step towards achieving reliable and consistent rapid manufacturing of advanced alloys. To date, a significant variability in reported mechanical properties and resulting mechanical behavior has been reported, creating the need to define efficient and systematic ways to investigate microstructure-processing-behavior relationships for this AM method. Towards this goal, the research presented herein focuses on the development of a Design-of-Experiments approach capable of providing directions in selecting manufacturing, material, and geometry parameters, which could be varied to investigate specific physical mechanisms involved in L-PBF which affect the final product. More specifically, crystallographic texture, grain size, dislocation structures, phase transformations, secondary phase and precipitation formations and their role in mechanical properties of an aluminum alloy are presented. In this context, a digital engineering method was developed to design and manufacture primitive geometries which reduce the mechanical and thermal effects on resulting microstructures of aluminum alloys in L-PBF. This design was used in a parametric AM fabrication plan with controlled volumetric heat input to produce statistically significant populations of material specimens for this investigation. On axis, melt-pool scale, in situ monitoring data collected during the AM process were combined with in situ data-informed thermal modeling and ex situ microstructural characterization. Furthermore, pre- and post-test X-ray and surface analyses were used to characterize porosity levels and roughness. Finally, in situ SEM level monotonic and cyclic loading was used to investigate the influence of specific microstructural parameters in properties and behavior of this alloy. The result of this effort will be to inform the AM process with optimal ranges of manufacturing parameters that could then be used for the design and fabrication of complex geometries.

Emine Tekerek   Drexel University
Vignesh Perumal   Drexel University
Alex Riensche   University of Nebraska-Lincoln
Lars Jacquemetton   Sigma Labs Inc
Darren Beckett   Sigma Labs Inc
Scott Halliday   Navajo Technical University
Prahalada Rao   University of Nebraska-Lincoln
Antonios Kontsos   Drexel University