Additive Manufacturing for Energy Applications IV: Processing and Advanced Materials Enabled by Additive Manufacturing
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Nuclear Materials Committee
Program Organizers: Isabella Van Rooyen, Pacific Northwest National Laboratory; Indrajit Charit, University of Idaho; Subhashish Meher, Idaho National Laboratory; Kumar Sridharan, University of Wisconsin-Madison; Xiaoyuan Lou, Auburn University; Michael Kirka, Oak Ridge National Laboratory

Wednesday 8:30 AM
March 2, 2022
Room: 261B
Location: Anaheim Convention Center

Session Chair: Xiaoyuan Lou, Auburn University; Kumar Sridharan, University of Wisconsin-Madison

8:30 AM  Invited
3D Printing Energetics for Gun Propulsion Technology: David Bird1; Elbert Caravaca1; Joseph Laquidara2; Ravindra Nuggehalli3; 1Picatinny Arsenal, US Army Combat Capabilities Development Command (CCDC); New Jersey Institute of Technology ; 2Picatinny Arsenal, US Army Combat Capabilities Development Command (CCDC); 3New Jersey Institute of Technology
    The US Army has been exploring additively manufactured (AM) energetic formulations over recent years with the key benefits being safer energetic material handling and improved ballistic performance. Department of Defense (DoD) researchers are examining where three dimensional printing (3DP) and energetic materials overlap in the fields of gun propulsion, explosives and pyrotechnics. Innovative 3DP formulations incorporating legacy energetic materials and novel energetic 3DP molecules are candidates for improving overall system performance and optimizing for lethality and accuracy demonstrating the US Army’s commitment to performance for future capability growth. A synergy between formulation and printing technique has led to understanding the design space for gun propellant stereolithography apparatus (SLA) and digital light processing (DLP) printing which involves understanding the cure depth to successfully print simple propellant geometries and combustion testing to gauge the performance. Commercial-off the shelf (COTS) printers were used to print all formulations. The background of formulation development and results will be presented.

9:00 AM  
Effective Sensitization Treatment for High-performance Steel Parts Made by Laser Powder Bed Fusion: Mitra Shabani1; Soumya Sridar1; Robert Hoffman2; Noah Sargent1; Owen Hildreth2; Wei Xiong1; 1University of Pittsburgh; 2Colorado School of Mines
    Sensitization surface treatment can improve the tensile and fatigue properties among other mechanical properties of additively manufactured alloy parts. However, this technique leads to surface carburization, which may negatively impact the performance of steel parts. In this research, the temperature and duration needed for decarburization are predicted for sensitized surface-treated stainless steel 316L parts made by laser powder bed fusion using the CALPHAD approach. Sensitized and etched 316L samples are then heat-treated at the designed temperatures and further characterized using electron microscopy and microhardness to evaluate the effectiveness of the decarburization. Tensile tests and tension-tension fatigue tests at different maximum stress levels are then performed on as-printed, sensitized, and decarburized samples to study the effect of both sensitization surface treatment followed by optimized heat treatment. This study demonstrates a pathway to effectively integrate heat treatment and surface modification for the improved mechanical performance of additive manufacturing components.

9:20 AM  
Co-design of Parts and Processing for Additively Manufactured Heat Exchangers: Nicholas Lamprinakos1; Ziheng Wu1; Junwon Seo1; Srujana Rao Yarasi1; Anthony Rollett1; 1Carnegie Mellon University
    A key advantage to additive manufacturing is the ability to directly fabricate parts with complex geometries. In the energy sector, this can be leveraged to create more efficient heat exchangers that would be difficult to produce using conventional processes. However, when printing intricate features, challenges such as thermal distortion must be overcome. In this project, high-temperature heat exchangers were designed to be printed from superalloy powder via laser powder bed fusion. Modifications to the input part geometry and processing parameters were explored together to optimize the printed components. This allowed for heat exchangers to be printed to the desired geometric tolerances for small internal features without sacrificing heat exchanger performance. Post-processing techniques, including abrasive flow machining, were also studied to reduce the internal surface roughness. A 20 kW prototype heat exchanger that is applicable to loading cycles at 200 bar and above 720C was fabricated.

9:40 AM  Invited
Ballistic Additive Manufacturing -- Versatile Solid-state Fabrication: Glenn Daehn1; Jianxiong Li1; Yu Mao1; Blake Barnett1; K. Sajun Prasad1; Anupam Vivek1; 1Ohio State University
    For the past few decades our team at Ohio State has developed several techniques for accelerating metal to very high speeds, commonly 500m/s to over 1km/s, usually for impact welding. When performed with sequential thin flat pucks, this can be a method for additive manufacturing. In many respects this is like building up bodies with cold spray, except the typical sizes are orders of magnitude larger and acceleration is usually driven by a rapid plasma expansion from optical or electrical energy. This method can be very energy efficient, allow graded compositions and preserve complex microstructures in the flyer metal. Preliminary results, process attributes as well as a long-term vision will be provided in this presentation.

10:10 AM Break

10:30 AM  
Compositionally Graded Joint of 316L Stainless Steel to A508 Low Alloy Steel by Additive Manufacturing: Xiaoyuan Lou1; Josh Le1; Houshang Yin1; Jingfan Yang1; 1Auburn University
    Most energy applications require dissimilar metal joining, done by welding, to manufacture components that can simultaneously serve different purposes while minimizing the material cost. One common example is the transition joint from austenitic stainless steel to ferritic steel. This study reports the design strategy, microstructure, and material properties of the compositionally graded joint of 316L stainless steel (SS) to A508 low alloy steel fabricated by laser direct energy deposition additive manufacturing (AM). Heat treatment, such as solution annealing, normalization, and tempering, is necessary to acquire adequate strength and toughness for A508 steel. Microstructural evolution of 316L SS, A508 steel, and transition region by heat treatment will be discussed. While heat treatment promotes recrystallization and phase transformation, the complex heat treatment cycle leads to elemental diffusion between alloys, grain coarsening, and intermetallic phase formation, and sensitization. A careful design of transition strategy minimizes the detrimental impacts from these metallurgical processes.

10:50 AM  
NOW ON-DEMAND ONLY - Direct Ink Writing of Ultra High Temperature Ceramics: Swetha Chandrasekaran1; Amy Wat1; Qi Rong Yang1; James Cahill1; Wyatt Du Frane1; Joshua Kuntz1; Marcus Worsley1; 1Lawrence Livermore National Laboratory
    Additive manufacturing (AM) of engineering materials that are lightweight and durable with excellent chemical and wear resistance continues to be an area of intense interest and study. Here,we demonstrate fabrication of ultra-high temperature ceramics such as boron carbide (B4C), zirconium diboride (ZrB2) and Hafnium diboride (HfB2) parts through direct ink writing at room temperature. 3D printed parts were made from aqueous, thixotropic ink with a solid loading ranging from 50.0 to 59 vol.%. The complex green bodies (B4C) are infiltrated with an aluminum matrix to obtain B4C-Al Cermets. 3D printing these ceramic materials could be used to optimize and design the lightweight armor materials or materials used for extreme applications. Complex shaped parts and parts with graded density can be easily fabricated through the DIW technique for molten metal infiltration to create Cermets which are used for ballistic testing devices. Prepared by LLNL under Contract DE-AC52-07NA27344.