Additive Manufacturing Benchmarks 2022 (AM-Bench 2022): Materials II: Microstructural Engineering
Program Organizers: Brandon Lane, National Institute of Standards and Technology; Lyle Levine, National Institute of Standards and Technology
Monday 3:30 PM
August 15, 2022
Room: Regency Ballroom III & IV
Location: Hyatt Regency Bethesda
Session Chair: Jake Benzing, National Institute of Standards and Technology
3:30 PM
(On Demand) Investigation of Co-free High Entropy Alloys Produced by Selective Laser Melting for Nuclear Applications: Hiroshi Oka1; Naoyuki Hashimoto1; Shigehito Isobe1; Shinichiro Yamashita2; 1Hokkaido University; 2Japan Atomic Energy Agency
Additive manufacturing is considered for application to advanced reactors because of its potential to enable new reactor designs. On the other hand, high entropy alloys (HEAs) are being studied as nuclear reactor materials because they show unique diffusion behavior and are expected to suppress the formation of irradiation defects under neutron-irradiated environments. In this study, FCC-type Co-free HEAs (Cr0.8FeMn1.3Ni1.3Alx HEAs) were built by Selected Laser Melting with varying process parameters, and the mechanical property and microstructure were investigated. As a result of the trial manufacture of build pieces with 48 process patterns, the specimen with a defect density of less than 0.02% was obtained. Room temperature tensile test exhibited 40% higher tensile strength compared to reference arc-melted specimen, which is due to the dislocation cell structure in as-built condition. Strength anisotropy was observed along build direction, but it can be reduced by post-build recrystallization heat treatment at 1150°C for 1.5h.
3:50 PM Invited
Microstructural Engineering in Steel 3D Printing with PBF Method: High-throughput Computational Design: Hamedreza Hosseinzadeh1; Mark Horstemeyer2; 1University of South Carolina; 2Liberty University
One of the challenges in metal additive manufacturing is the unwanted microstructure achieved. In this research, high-throughput simulations were done for steel 3D printed with powder bed fusion (PBF) method to check the local cooling curves at different print parameters. Then, local grain topology and phase percentages were mapped. The extreme possibilities of in situ controlling microstructure were checked to achieve what we wanted at the end of the print. Series of weighted numbers for the print parameters and steel phases were introduced to relate and weight effect of print parameters on the final microstructure. These weighted numbers could then be used to set print parameters based on the final goal microstructure in any other shapes of steel 3D printed samples with the PBF method to reduce the number of trials and errors. The results could also be a platform for the control system in digital twin metal additive manufacturing.
4:20 PM
Microstructural, Tribological and Electrochemical Analyses of Additive Manufactured Metallic Alloys for Engineering Applications: Waseem Haider1; Ali Raza1; 1Central Michigan University
The manufacturing processes have been continuously evolving due to the ever-increasing diversity of the applications. In that perspective, additive manufacturing (AM) has become important due to its design freedom and improved properties. In certain applications however, the properties are surface dependent. This research involves surface modification of different AM alloys through heat treatment and drop casting. Different electrolytes of changing concentrations have been used to replicate operating conditions ranging from moderate to aggressive. The corrosion behavior of surface modified alloys is analyzed through electrochemical measurements. The effect of changing electrolytes on the inherent cellular structure of the alloys has also been measured. Atomic force microscopy has been used to assess the surface damage on a macro scale. X-Ray photoelectron spectroscopy is used to understand the nature of the species formed on the surface. Finally, the electro-kinetic diagrams (E-pH-i) have been developed to predict a safe E-pH range for the alloys.