Additive Manufacturing Benchmarks 2022 (AM-Bench 2022): Residual Strain/Stress and Distortion I: Diffraction-Based Measurements
Program Organizers: Brandon Lane, National Institute of Standards and Technology; Lyle Levine, National Institute of Standards and Technology
Tuesday 1:30 PM
August 16, 2022
Room: Cabinet/Judiciary Suite
Location: Hyatt Regency Bethesda
Session Chair: Donald Brown, Los Alamos National Laboratory
1:30 PM Invited
Evaluation of Strains in AM–Bench Samples via Energy Dispersive Diffraction at Cornell High Energy Synchrotron Source: Hazar Seren1; Thien Phan2; Amlan Das3; Kelly Nygren1; Peter Ko1; Katherine Shanks3; Lyle Levine4; 1Cornell High Energy Synchrotron Source; 2Lawrence Livermore National Laboratory; 3Cornell University; 4National Institute of Standards and Technology
The residual stress state of an additively manufactured component can significant impact on service life. Accurate and highly controlled measurements of these stresses play a crucial role in validating predictive AM manufacturing models. To directly and non-destructively map the residual elastic strains in AM-bench bridge structure geometry samples, Energy dispersive X-ray diffraction experiments (EDD) were conducted at the Structural Materials Beamline (SMB) at the Cornell High Energy Synchrotron Source (CHESS). In these experiments, a polychromatic X-ray beam with an energy range between 50 keV to 150 keV was utilized to evaluate high resolution (spatial) residual strain maps of AM – Bench samples. In this presentation, we will review the EDD technique and the AM – Bench experiment in detail. The data analysis strategies, including different analysis algorithms and their implications, will be discussed.
2:00 PM Invited
Neutron Diffraction Stress Measurements on an AM Bench 2022 Bridge Artifact: Thomas Gnaupel-Herold1; Thien Phan1; Lyle Levine1; Jeffrey Bunn2; Paris Cornwell3; 1National Institute of Standards and Technology; 2Oak Ridge National Laboratory; 3Oak Ridge National Lab
We report on the results of neutron diffraction stress measurements on an IN718 bridge artifact. The specimen has the same geometry as the AMB 2018 (IN625) artifact. Stresses follow a similar pattern as before (AMB 2018) with strong, longitudinal tensile stresses near 400 MPa near the surface and compressive stresses up to -400 MPa in the bulk. Stress magnitudes are highest in the longitudinal direction near the surface, and in the build direction in the bulk. The comparison to the 2018 artifact shows appreciable differences between stresses both in magnitudes and spatial distribution.
2:30 PM Invited
In Situ High-energy X-ray Diffraction during Compression of Additively Manufactured Inconel 625 at Temperature: Darren Pagan1; Katherine Shanks2; Robert Carson3; James Belak3; 1Pennsylvania State University; 2Cornell University; 3Lawrence Livermore National Laboratory
A common paradigm for micromechanical modeling is to fit micromechanical parameters to reproduce macroscopic stress-strain responses. A downside of this approach is that often non-unique sets of micromechanical parameters are capable of capturing a given macroscopic response. To address this issue, the ExaAM program has gathered bulk micromechanical data for crystal plasticity model fitting as part of a larger effort to simulate laser powder bed fusion from build to final properties. In particular, lattice strain data has been collected using high-energy X-ray diffraction during in situ high-temperature compression testing of additively manufactured Inconel 625 at the Cornell High Energy Synchrotron Source. Here we describe the data collection, lattice strain results, and connections to crystal plasticity model development.
3:00 PM Break