Additive Manufacturing: Advanced Characterization with Synchrotron, Neutron, and In Situ Laboratory-scale Techniques: Synchrotron, Neutron, and In Situ Techniques: Keynote
Sponsored by: TMS: Additive Manufacturing Committee
Program Organizers: Fan Zhang, National Institute of Standards and Technology; Tom Stockman, Los Alamos National Laboratory; Tao Sun, Northwestern University; Donald Brown, Los Alamos National Laboratory; Yan Gao, Ge Research; Amit Pandey, Lockheed Martin Space; Joy Gockel, Wright State University; Tim Horn, North Carolina State University; Sneha Prabha Narra, Carnegie Mellon University; Judy Schneider, University of Alabama at Huntsville
Monday 8:00 AM
February 24, 2020
Room: 8
Location: San Diego Convention Ctr
Session Chair: Fan Zhang, National Institute of Standards and Technology; Tom Stockman, Los Alamos National Laboratory
8:00 AM Introductory Comments
8:10 AM Keynote
3D Printing, Porosity, Synchrotron Experiments and Machine Learning: Anthony Rollett1; 1Carnegie Mellon University
3D printing of metals has advanced rapidly in the past decade and is used across a wide range of industry. At the microscopic scale much work is required to quantify, understand and predict defect- and micro-structures, which affect properties such as fatigue resistance. Dynamic x-ray radiography (DXR) provides ultra-high speed imaging of laser melting of metals and their powders. This has, e.g., enabled the keyhole and hot cracking phenomena to be quantified. Computer vision (CV) has successfully classified different microstructures, including powders. The power of CV is further demonstrated by its ability to detect and classify defects in the spreading of powder. High speed synchrotron x-ray diffraction is beginning to provide new information on solidification and phase transformation in, e.g., IN718, Ti-6Al-4V and stainless steel. High Energy (x-ray) Diffraction Microscopy (HEDM) experiments also is also providing data on 3D microstructure and elastic strain in 3D printed materials.
8:40 AM Keynote
Using High Energy X-ray Diffraction to Probe Additively Manufactured Metals over a Range of Length and Time Scales: John Carpenter1; Donald Brown1; Bjorn Clausen1; Maria Strantza1; Jason Cooley1; Reeju Pokharel1; Erik Watkins1; 1Los Alamos National Laboratory
Our efforts to characterize the processing/microstructure/properties/performance relationship of additively manufactured materials across many length and time scales utilizing high-energy x-ray scattering techniques at the Advanced Photon Source is presented. As an example of studying the effect of processing on microstructure, high energy x-ray diffraction has been used to monitor microstructural evolution in-situ during additive manufacture of 304L stainless steel and Ti-6Al-4V with sub-second time resolution and sub 0.1mm spatial resolution. Both material feedstocks are wire and deposited using a metal inert gas welding set-up. The intent is to study this additive technique as it pertains to the repair of existing objects. Specifically, the evolution of phase fractions, liquid and multiple solid phases, is monitored immediately following deposition, during solidification, and during cooling. This information can be utilized in current process – microstructure models in order to inform and validate the appropriate kinetics which lead to the resultant microstructure after deposition.
9:10 AM Keynote
Utilization of Backscattered Electrons for Process Monitoring During Electron Beam Melting: Carolin Korner1; Christopher Arnold1; Christoph Breuning1; 1University of Erlangen-Nuremberg
During electron beam melting, demanding processing conditions such as high temperature, vacuum conditions and X-ray Radiation impede the continuous operation of standard process monitoring devices like light-optical camera systems. To overcome this deficit, detection of backscattered electrons is a highly promising approach. It delivers a signal, which is sensitive to variations of process parameters while the detector is unsusceptible to the harsh environmental conditions. A detection system for backscattered electrons is implemented in an in-house EBM system and used for the acquisition of electron optical images of the molten surfaces as well as for the record of the in-situ signal during melting. The data is correlated afterwards to the as-built specimens to demonstrate the high usability for process monitoring during EBM.
9:40 AM Break
10:00 AM Keynote
The Important Contribution of Synchrotron X-ray and Neutron Measurements to Metal Additive Manufacturing Benchmarks: Lyle Levine1; Fan Zhang1; Thien Phan1; Maria Strantza2; Bjorn Clausen3; Donald Brown3; Darren Pagan4; Andrew Allen1; Jan Ilavsky5; 1National Institute of Standards and Technology; 2Lawrence Livermore National Laboratory ; 3Los Alamos National Laboratory; 4Cornell High Energy Synchrotron Source; 5Advanced Photon Source
The Additive Manufacturing Benchmark Test Series (AM-Bench) is a continuing series of highly controlled benchmark measurements for additive manufacturing that allows modelers to test their simulations against rigorous additive manufacturing benchmark test data. AM-Bench aims to provide high-fidelity sets of coordinated in situ and ex situ measurements and process data, covering the full range from feedstock material to finished part. The unique capabilities afforded by synchrotron X-ray and neutron instruments have provided invaluable information on aspects such as spatially-resolved elastic strains and stresses within the as-built parts, evaluations of the alloy phases and elemental segregation, and in situ measurements of the growth of precipitates during post-build heat treatments. These measurements were conducted at the NIST Center for Neutron Research, the Cornell High Energy Synchrotron Source, and three beamlines at the Advanced Photon Source. Future benchmark measurements are expected to expand upon the use of synchrotron X-ray and neutron measurements.
10:30 AM Keynote
Investigating the Mechanics of Additively Manufactured Materials Using Neutron Diffraction: Allison Beese1; Zhuqing Wang2; Alexandru Stoica3; Dong Ma3; 1Pennsylvania State University; 2Kennametal; 3Oak Ridge National Laboratory
Additive manufacturing (AM) of metals imparts complex thermal histories to the material being deposited, resulting in the buildup of residual stresses and the formation of complex microstructures. We will discuss our efforts utilizing mechanical testing with in situ neutron diffraction to interrogate temperature-dependent properties of additively manufactured Inconel 625 (AM-IN625). We investigated grain-level deformation behavior under compression at room and elevated temperatures and showed that dynamic strain aging was absent in AM-IN625 under the same conditions for which it was active in conventionally processed IN625 (CP-IN625), having implications for the performance of AM-IN625 in service. Additionally, AM-IN625 had a faster stress relaxation response than CP-IN625, having implications for the development of residual stresses during AM processing. The differences in temperature-dependent mechanical behavior in AM-IN625 versus CP-IN625 were found to be due to differences in microstructural features and have implications for tailoring microstructures via AM for desired properties.
11:00 AM Keynote
Sensor Enabled Material Optimization in Powder Bed Fusion Additive Manufacturing: Justin Gambone1; Subhrajit Roychowdhury1; Xiaohu Ping1; 1GE Research
PBFAM is becoming an increasingly utilized manufacturing technique for multiple industrial applications and with this the need for robust and high-quality materials has increased. Current techniques develop process parameter combinations that are applied over regions of a part, segmented based on drastic geometry shifts. This can lead to material debits in sub-sections of the part as the underlying variation in thermal leakage is not properly accounted for to maintain a consistent process. Optic train sensors imaging the region around the meltpool and local area sensors capturing post-weld information provide a path to continuously characterize the build behavior. The focus of this work is to leverage these sensors to provide insights which govern material behavior, allowing the assessment of a part throughout its volume. The results of which are used to further improve the build process through the local control of parameters using a high definition segmentation and scanning strategy.