2024 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2024): Process Development: Direct Energy Deposition
Program Organizers: Joseph Beaman, University of Texas at Austin
Tuesday 1:30 PM
August 13, 2024
Room: 416 AB
Location: Hilton Austin
Session Chair: Frank Brueckner, Fraunhofer IWS Dresden
1:30 PM Cancelled
EHLA: Introducing High-speed Directed Energy Deposition: Josh Barras1; 1TWI Ltd
Extreme High-speed Laser Application (EHLA) is an emerging metallic powder deposition process that stems from laser directed energy deposition (L-DED). Developed as a leading surface coating technology for rotationally symmetric components, most notably for brake rotors, turbomachinery and hydraulic cylinders. EHLA can deposit at speeds of several hundred metres per minute and presents the first fusion process that can apply thin coatings in the range of 50-250 micrometres, which is a capability space conventionally serviced by thermal spray and plating techniques. EHLA is disrupting the status quo, thanks to several traits that make it both technologically and commercially advantageous. With the advancement of new kinematic machines, EHLA can also be realized for freeform manufacturing opportunities including additive manufacturing, dissimilar material joining, repair, and complex surfaces. Research is presented on the major steps made to realizing this impactful solution. Alloys investigated include nickel superalloys and titanium for aerospace manufacturing.
1:50 PM
A Novel Metal Deposition Technique for Embedding Fiber Optic Sensors in Metal Components: Cesar Dominguez1; Donald Johnson1; John Bernardin1; Doug Meredith2; 1Los Alamos National Laboratory; 2Los Alamos National Lab
Traditional instrumentation processes consist of placing sensors on the surface or within prefabricated cavities of components. However, these methods can be intrusive or interfere with the proper fit up of layered mechanical parts. As a result, due to limited instrumentation strategies and integration technologies for embedded sensing, mechanical assemblies often lack the capabilities for gathering high fidelity response characteristics during tests. Generally, there is a desire to increase test fidelity by increasing sensing quality and quantity. However, the further addition of instrumentation can exacerbate performance discrepancies of individualized components or assemblies. Fiber optic-based embedded sensing can be a pathway for obtaining minimally-intrusive distributed data during in-situ monitoring operations. As such, there is a critical need for developing techniques for embedding fiber optics within mechanical components. This research presents a novel (patent pending) low-temperature metal deposition approach for consolidating fiber optic-based sensors within metal components via electrodeposition.
2:10 PM
Predicting Melt Pool Thermal Distribution in Ti-6Al-4V Directed Energy Deposition Using Machine Learning: Sung-Heng Wu1; Usman Tariq1; Ranjit Joy1; Muhammad Arif Mahmood2; Frank Liou1; 1Missouri University of Science & Technology; 2Missouri S&T Intelligent Systems Center
Ti-6Al-4V's high strength-to-weight ratio and thermophysical properties make it a compelling target for directed energy deposition (DED) components. The printed material's strength and fatigue properties are strongly related to the solidification and microstructure, which results from thermal gradients inherent to DED processes. Accurately predicting the melt pool thermal distribution and geometry is therefore crucial for enhancing the quality of the DED-fabricated parts. This study introduces the use of advanced machine learning models, including XGBoost, Gated Recurrent Units (GRU), Long Short-Term Memory (LSTM), and Bidirectional LSTM (Bi-LSTM), to predict and analyze the thermal distribution of the melt pool during the DED process with Ti-6Al-4V. The performance of each model was evaluated based on its computational efficiency and predictive accuracy. The comparative analysis of computational time and accuracy among the models provides insights into their practical applications, guiding future research and industrial applications in additive manufacturing.
2:30 PM
Powder Feed Mechanism for Convection of High-Cohesion, Sub-20-Micron Powders in Directed Energy Deposition: John Byers1; Adam Eungard1; Joseph Jafari1; Jennifer Bennett1; 1United States Military Academy at West Point
Functionally graded material (FGM) ceramics are a promising material for thermal applications to reduce the stress concentrations due to different thermal expansion coefficients at dissimilar material joints. Directed Energy Deposition (DED) enables processing of these FGMs by varying composition during deposition. However, ultra-high temperature ceramics, such as Titanium Diboride, cannot currently be deposited by DED. Using a reactive laser deposition approach may enable deposition of these materials but there are powder feed system limitations. Boron powder exhibits higher cohesion, lower density, and smaller particle sizes compared to traditional DED powders resulting in poor flowability. A feed system was developed by combining a feed screw and powder agitator to facilitate the delivery of boron powder to the mixing chamber of DED systems at precise and variable feed rates. The feed system successfully conveyed boron powder at variable rates enabling control over percent composition of boron and titanium to create a FGM.
2:50 PM
Development of a Powder Delivery Control Model for Precise Multimaterial Deposition via Laser Directed Energy Deposition: Faith Rolark1; Rujing Zha1; KenHee Ryou1; Jihoon Jeong2; Jian Cao1; 1Northwestern University; 2Texas A&M University
Powder-blown laser directed energy deposition (L-DED) expanded the material design space by offering the ability to deposit multiple powder feedstocks simultaneously, enabling the fabrication of functionally graded materials. However, achieving the desired material distribution in multimaterial parts presents challenges due to transient deposition behavior resulting in irregular gradients. Here, we developed a model for precise powder delivery control in a custom L-DED system by tuning multiple powder flow rates to achieve varying alloy gradients and correlating powder flow with feedstock proportions in the printed blend. Powder flow was modeled as a first-order transfer function with an initial delay for powder transport. The proportions of each constituent alloy in the printed blend were interpolated based on the concentration of elements unique to each feedstock, characterized via energy-dispersive X-ray spectroscopy. This work provides crucial insights for the design and optimization of complex multimaterial distributions in functionally graded materials for high-performance applications.
3:10 PM
Effect of Laser Power on Mechanical Property of Additive Manufactured Ti6Al4V-W-TiC for Aerospace Application: Rasheedat Mahamood1; Stephen Akinlabi2; T-C Jen3; Sisa Pityana4; Martin Birkett2; Esther Akinlabi2; 1Northumbria University / University of Johannesburg; 2Northumbria University; 3University of Johannesburg; 4CSIR Main Campus
Ti6Al4V is an important alloy with high strength-to-weigh ratio used in aerospace industry. The weight saving that can be provided by this material can further be enhanced if the properties can further be improved for application deserving high hardness and high temperature resistance such as aerospace engine parts. In this paper, we investigate the influence of laser power on the microstructure and microhardness of laser metal deposited tungsten and titanium carbide powders on Ti6Al4V substrate. The scanning speed was maintained at 5 mm/sec while the powder flowrate of tungsten and TiC were maintained at 0.5 rpm. The gas flowrate was kept constant at 2 l/min while the shield gas was maintained at 15 l/min. The laser power was varied between 1000 and 2000 watt. The microstructure of the samples were studied using scanning electron microscope and the microhardness also studied using microhardness indenter. The results are presented and fully discussed.
3:30 PM
Electroslag Additive Manufacturing (ESAM) of Inconel 625: Adam Stevens1; Paritosh Mhatre1; Christopher Masuo1; Soumya Nag1; William Carter1; Jesse Heineman1; Sarah Graham1; Andres Rossy1; Rangasayee Kannan1; Peeyush Nandwana1; Alex Roschli1; Andrzej Nycz1; Sudarsanam Babu1; Brian Post1; 1Oak Ridge National Laboratory
Electroslag strip cladding, commonly used for cladding corrosion-resistant materials onto the inner surface of chemical process vessels, is under evaluation as a high-throughput method for metal additive manufacturing. Initial trials have been performed with Inconel 625. We report key mechanical and microstructural properties with comparison to other additive and conventional (e.g., casting) methods for the manufacture of Inconel 625 near net shapes and present a vision for the development of electroslag additive manufacturing (ESAM) systems.