2024 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2024): Materials: Metals II
Program Organizers: Joseph Beaman, University of Texas at Austin
Tuesday 8:00 AM
August 13, 2024
Room: 602
Location: Hilton Austin
Session Chair: Sweta Baruah, University of Tennessee Knoxville
8:00 AM
Novel Metal Additive Manufacturing using Innovative Polymer-Metal Composite: In-situ Monitoring, Microstructure and Mechanical Analyses: Arnoldas Sasnauskas1; Minh-Son Pham2; Rocco Lupoi1; 1Trinity College Dublin; 2Imperial College London
There are various drawbacks to using metallic 'loose' powder in laser metal additive manufacturing (LMAM) such as health hazards, difficulty in switching materials and recyclability. Recent research on a novel polymer-metal composite for LMAM has displayed great potential in mitigating these issues while delivering promising material properties. The selection of polymer binder can greatly increased properties such as hardness and yield strength. This presentation will cover a thorough investigation utilizing in-situ melt pool analysis combined with microstructural EBSD and XRD.
8:20 AM
Magnetic Properties of Binder-Jetted Soft Magnetic Toroidal Inductor: Emrecan Soylemez1; Emre Sari2; Mehmet Fatih Yalcin1; Ali Cem Cetin1; Zeki Aslan1; Baran Bulut1; 1Istanbul Technical University; 2Core Elektronik
Additively manufactured soft magnetic parts enable enhance magnetic performance with a complex design. Binder jetting followed by sintering results in a uniform grain size distribution, enabling the tailoring of magnetic performance compared to fusion-based additive manufacturing. In this study, binder jet additive manufacturing of Fe-50Ni soft magnetic permalloy, a widely utilized soft magnetic alloy known for its high permeability and low coercivity, is employed to investigate the effects of fine (d_50=14 μm) and coarse (d_50=31 μm) powder sizes, as well as sintering conditions, on the density and magnetic characteristics of toroidal core inductors. Powder samples were additionally sintered in the cylindrical alumina to distinguish the impact of binder on sintering. Cubes and toroidal parts were printed, and sintered in atmospheric and vacuum furnaces. Density measurements were conducted, and the BH curves along with the core loss behavior of the specimens were analyzed at 5 Hz, 50 Hz, and 1000 Hz.
8:40 AM
Thermal-Assisted Direct Ink Write 3D Printing of Stainless Steel 316L Colloidal Pastes: John Obielodan1; Taylor Nisius1; Bert Wolle1; 1University of Wisconsin-Platteville
Additive manufacturing of metallic structures using sinter-based approaches are continuously being explored as alternatives to high-powered laser or electron beam processes. They enable indirect conversion of powdered metals, ceramics, or composite materials to solid structures at low costs. This work investigates the use of thermal-curable polymer matrix colloidal pastes for the fabrication of stainless steel (SS) 316L structures. Green samples were fabricated using highly loaded pastes of SS 316L and subsequently sintered at different temperatures to obtain high-density structures. Tests were conducted to understand (i) the optimal rheological properties of the colloidal pastes for 3D printing using direct ink write, (ii) the heating conditions for curing the deposited materials for shape fidelity, and (iii) to establish the sintering temperature paths. The parameters were correlated with the microstructures, densities, and other physical properties of printed samples.
9:00 AM
Direct Writing of Cu Film on Flexible Substrate Under Ambient Environment: Janghan Park1; Yaguo Wang1; 1University of Texas Austin
Direct writing of metal features on flexible substrates with additive manufacturing (AM) is challenging due to polymer heat sensitivity. Traditional AM, like laser selective melting with continuous wavelength laser, isn't viable for flexible electronics due to large heat affected zones. Current techniques, like flash light and intense pulsed light sintering, yield low electrical conductivity. Here, we introduce femtosecond selective laser sintering (fs-SLS) for directional metal film writing on flexible substrates under ambient conditions. Femtosecond lasers have small heat affected zones but cause metal particle ablations due to hot electron effects. Fs-SLS uses double-pulse femtosecond lasers to sinter metal nanoparticles, eliminating hot electron effects and reducing the heat affected zone. Another advantage is preventing metal particle oxidation even under ambient conditions. A continuous copper film was sintered onto a polyimide substrate without observing damage. Bending tests showed no cracking after 2000 cycles, with higher electrical conductivity than films from other techniques.
9:20 AM
Use of Cored Wire in the Optimisation of New Alloys for Laser Powder Bed Fusion with Tailored Mechanical and Corrosion Properties: Edward Palmer1; Daniel Butcher1; Shahin Mehraban1; Matthew Ritchie1; Talal Abdullah1; Leonor Neto2; Gavin Stratford3; Nicholas Lavery1; 1Swansea University; 2Welding Alloys Group; 3LSN Diffusion
The utilization of cored wire is of significant interest in both wire and powder-based Additive Manufacturing (AM) processes, providing the ability to undertake in-situ alloying additions and rapidly assess the influence of composition on properties. This study investigates the influence of varying molybdenum levels on the mechanical and electrochemical behaviour of 316L built by Laser Powder Bed Fusion (L-PBF). The cored wire was processed using Ultrasonic Atomisation (UA) to manufacture powders with varying levels of molybdenum built into suitable test samples using L-PBF. Mechanical testing included tensile strength, hardness, and density, while corrosion resistance was assessed through changes in corrosion potential, linear polarisation resistance and pitting potential. This research demonstrates the ability to optimise alloy compositions, facilitating the development of tailored 316L steels for AM with desired mechanical and corrosion properties. This approach will be extended for use in new alloys (e.g. high entropy alloys).
9:40 AM Break
10:00 AM
Towards Affordable Aluminum Additive Manufacturing: Considerations on the Manufacturing of Non-Explosible NExp-1 AlSi10Mg on Medium-Wattage Systems: Fatma Depboylu1; Andrei-Alexandru Popa1; Tomohiro Oyama2; Yushi Ono2; 1University of Southern Denmark; 2Taiyo Nippon Sanso Corporation
Laser powder bed fusion of aluminum poses safety challenges due to the reactive nature of the feedstock. The non-explosible claim of the NExp-1 AlSi10Mg from Equispheres has been validated through Lower Explosive Limit and Minimum Ignition Energy, ranking it in the lowest explosion class per JIS Z 8817. This relieves the need of otherwise costly investment in the manufacturing environment. With its enhanced flowability and homogenously spherical particles above 100 µm in average size distribution, the feedstock facilitates faster build rates at high layer thickness. Attempting to utilize this powder on a 400 W Yb laser, well below the 700 W for which it was designed, leads to atypical energy behavior within the melt pool. After the necessary process parameter development, the melt pool and microstructure of fabricated samples were analyzed, with density and mechanical characteristics highlighting the promising future of affordable aluminum additive manufacturing for lightweight applications.
10:20 AM
Mold Design using Binder-Jetted Sand for Aluminum Casting: Jacob Rodriguez1; 1W.M. Keck Center for 3D Innovation
The purpose of this project is to design a mold in collaboration with ExOne, for a helicopter ejection handle. The mold will be printed using binder jetting 3-D printing technology, made of silica sand, and will be cast using Aluminum A356. Throughout the project various the team was provided feedback and suggestions in improvements on mold design, and were guided in the importance of parting lines, the minimum thickness of the part, and many other important factors to consider for casting. The team conducted weekly meetings to discuss mold designs and casting practices. As prototypes were cast using scrap metal, simulations for the solidification analysis, and tensile tests were conducted with the cast metal. The team created two final iterations, a horizontal and vertical mold which were cast and analyzed. The horizontal mold proved to be the most successful when casting, with almost no areas left unfilled.
10:40 AM
Effects of Powder Characteristics of Different Alloy Powders on Part Quality in Area Printing® Additive Manufacturing: Ben Fotovvati1; Nicholas Ferreri1; Ethan Le1; Subin Shrestha1; Ning Duanmu1; 1Seurat Technologies
As laser powder bed fusion (LPBF) technology has transitioned from prototyping to end-use parts, understanding the role of the powder properties needed to reliably produce parts of acceptable quality becomes critical. In this study, different alloy powders from different manufacturers are tested for flowability, spreadability, particle size distribution, and morphology using scanning electron microscopy (SEM). The tested alloys include stainless-steel 316L, Nickel-based super alloy 625 (Inconel 625), M300 maraging steel (also known as Tool Steel 1.2709 and 18Ni300), AlSi10Mg, and Ti6Al4V. These powders were then used as feedstock in the Area Printing® process to print density cubes with a wide range of laser parameters to correlate the powder characteristics with part density. The results suggest a strong correlation between these characteristics and the density of the parts as well as among the powder characteristics themselves.
11:00 AM
Graph Methods for Alloy Informatics and Multi-Material Design: Marshall Allen1; Richard Malak1; Raymundo Arroyave1; 1Texas A&M University
Multi-material metal additive manufacturing facilitates the production of compositionally graded alloy (CGA) structures, offering a versatile solution for meeting diverse performance criteria within a single engineering part or for streamlining experimental data collection through multi-material test samples. However, challenges such as the formation of deleterious phases and cracking have impeded the successful fabrication of many CGAs. While various CALPHAD-based approaches, including ternary mapping and robotic path planning methods, have been proposed and demonstrated to mitigate these challenges, they exhibit limitations in scalability and reusability, respectively. In this study, we propose leveraging graph databases (GDBs) to overcome these limitations and establish a scalable, data-reusable framework for alloy informatics and multi-material design. Harnessing GDBs introduces novel avenues for materials design exploration and automated compositional grading. Moreover, employing graph-based methodologies enables the development of manufacturable CGA components, integrating the materials design process with user-defined physical geometries.
11:20 AM
Probing the Process Window Boundaries in Powder Bed Fusion-Laser Beam of Ti-6Al-4V: Justin Miner1; Austin Ngo2; Christian Gobert1; Tharun Reddy1; John Lewandowski2; Anthony Rollett1; Jack Beuth1; Sneha Prabha Narra1; 1Carnegie Mellon University; 2Case Western Reserve University
Parameter development for powder bed fusion - laser beam (PBF-LB) involves mapping the effects of process parameters such as laser power and scanning velocity on process outputs like porosity. Specifically, the process window is identified as combinations of process parameters that minimize defects such as Lack-of-Fusion (LoF), keyhole porosity, and balling. However, our work reveals that not all points within this process window are equal. Some methods of process mapping, such as utilizing part density and assuming defect boundaries follow lines of constant energy density, may not adequately identify defects because they do not capture the underlying phenomena. We further identify sparse LoF porosity using micro-CT, and identify its cause as melt pool geometry variability. Our findings highlight inherent process nuances and their impact on the defect boundaries defining the process window in PBF-LB. We present limitations within parameter development approaches and the importance of thorough evaluation of process parameters.
11:40 AM
Functional Gradients in the Ti-Ta-Nb System: Jennifer Glerum1; Benjamin Ellyson1; Raiyan Seede1; Michael Juhasz1; Brandon Bocklund1; Nicholas Ury1; Aurelien Perron1; Kaila Bertsch1; 1Lawrence Livermore National Laboratory
Additive manufacturing (AM) of functionally graded materials (FGMs) is of interest for joining dissimilar metals to enable novel ways of optimizing material response. FGMs of lightweight, structural alloys to high-melting temperature refractory alloys are of particular interest for aerospace, fusion, and defense applications. In this work, a framework for optimizing process parameters to produce fully-dense FGMs by directed energy deposition (DED) is explored in the Ti-Ta-Nb ternary alloy system. Single tracks of Ti, Ta, and Nb are analyzed for melt pool dimensions and extent of mixing with the substrate as a function of process parameters, and binary elemental blends/gradients are evaluated to develop a formulaic approach for fabricating FGMs. The microstructure and compositions are compared to equilibrium Calphad-based modeling predictions, demonstrating that the non-equilibrium conditions in DED play a significant role in microstructure evolution. Finally, mechanical properties of these gradients are evaluated to provide insights into their future applications.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.LLNL IM release number: LLNL-ABS-863175