Late News Poster Session: Additive Manufacturing
Program Organizers: MS&T19 Administration, MS&T PCC

Tuesday 4:45 PM
October 1, 2019
Room: Exhibit Hall CD
Location: Oregon Convention Center

P3-38: 3D Characterization of Defects in Deep-powder-bed Manufactured Ti-6Al-4V and Influence on Tensile Properties: Joe Elambasseril1; Shenglu Lu2; Yapeng Ning2; Nan Liu2; Jian Wang2; Milan Brandt1; Huiping Tang2; Ma Qian1; 1RMIT University; 2State Key Laboratory of Porous Metal Materials, Northwest Institute for Nonferrous Metal Research
    A systematic study has been performed to investigate the effects of positional variation of porosity, microstructure and mechanical properties of vertically built long Ti-6Al-4V rods by selective electron beam melting (SEBM) up to the maximum building height (300 mm) of the Arcam A2 system. The as-built Ti-6Al-4V rods were characterised in detail using high-resolution micro focus X-ray computed tomography (µCT). The reconstructed three-dimensional (3D) images allowed a quantitative assessment of the sphericity, equivalent diameter and spatial distribution of pores in the rod as a function of building height. A number of new findings were made, which, together with the microstructural details and mechanical property data obtained from different segments of these long rods, are expected to improve the current understanding of the capabilities and limitations of the SEBM process for additive manufacturing of Ti-6Al-4V.

P3-39: 3D Printed Electronic Sensors and Authenthication: Pedro Cortes1; Michael Walker1; Guraarashjot Multani1; Carolyn Carradero1; Dillon Kennedy1; Brian Zellers1; Eric MacDonald1; 1Youngstown State University
    The present work has investigated the production of 3D printed parts for the incorporation of electronic components. The initial efforts have concentrated on studying an overmolding process on rigid and flexible Stereolithography (SLA) printed parts to produce encapsulated electronic structures. Here, the incorporation of a microcontroller, and a chemical sensor based on functionalized single wall carbon nanotubes (SWCNTs) has resulted in the detection of hazardous gases. In this work, the electrical connections across the printed platform has been performed using an Optomec 3D printer. Additionally, distinctive nanoparticles have been incorporated into the printed structures in order to induce an authentication background. This fingerprint framework has been investigated on clear as well as opaque printed parts. Lastly, an algorithm imaging software is being used as the screening tool for detecting these unclonable parts.

P3-40: 3D Printing of Refractory Alloys for Extreme Environments: John Porter1; Youping Gao1; 1Castheon, Inc.
     Refractory alloys have extraordinary resistance to heat and wear and are the desired material for extreme environment applications on space-craft, missiles, and hypersonic vehicles. 3D printing enables a superior shape producing capability. Here, successful 3D printing of high quality Niobium C103 alloy components is demonstrated, with process optimization based on builds of “Gao blocks”, a shape incorporating a complex geometry. A hypersonic leading edge concept, with a porous insert to allow for cooling fluid behind the leading edge, has been built in a single operation, with an external wall thickness of 250 µm. Other components include thruster designs with active cooling. The microstructure of the niobium parts shows, showing build traces and grain structure, demonstrate a homogeneous material as-built, as required for the application, and show stability after heat treatment at 1600°C for 2 hours. Mechanical properties of witness coupons are consistent with wrought properties for Niobium C103.

P3-41: Accelerating Alloy Development with Directed Energy Deposition: Melanie Lang1; 1Formalloy
     Traditional bulk metallic alloy development is a time-consuming process, requiring sequential melting and casting of individual alloy compositions. With new additive manufacturing (AM) technologies such as Directed-Energy Deposition (DED), opportunities arise to rapidly development new alloys quickly, efficiently, and optimized for AM technologies. Many conventional alloy powders were developed prior to AM technology, and as such most of these materials are unsuited for AM. Materials producers desire high throughput methods to experimentally synthesize new alloy compositions. A powder feed system with mini-hoppers are ideal for material development applications since only a small amount of each alloy is required to deposit a sample for analysis. With a single alloy development feeder (ADF), 16 various alloy or alloy combinations can be deposited, and multiple ADF feeders can be combined to enable many alloy combinations through sequential or simultaneous operation. The revolver-style design rotates the hoppers to access the desired hopper quickly.

P3-42: Advantages of Open-Source Additive Manufacturing: Ulf Ackelid1; Ulric Ljungblad1; Patrik Ohldin1; Robin Stephansen1; Martin Wildheim1; Fredrik Ostman1; 1Freemelt AB
     Additive Manufacturing (AM) is a business area where most suppliers employ a closed-source approach. Users are constrained to supplier-defined beam scanning patterns, parameters and feedstock. Consequently, academic users cannot uncover the true AM potential. "Open-source" (OS) refers to product designs that are publicly accessible and free to modify and share. OS was originally a specific way of building computer code, and has evolved into other areas promoting open, collaborative participation and community-oriented development. OS philosophy makes it possible for all members of a business ecosystem to interact and develop products in a shorter time. Freemelt develops an AM research platform based on Electron Beam Powder Bed Fusion, with open access to beam steering and other system functionality. The platform is designed for academia and other high-level users who need maximum freedom in terms of beam control, powders and process monitoring. Freemelt’s open-source philosophy will be detailed in this presentation.

P3-43: Compression Behavior of Additively-manufactured Polymeric and Metallic Cellular Solids Composed of Tachi-Miura Polyhedron Cells: Takahiro Kunimine1; Hiromi Yasuda2; Jinkyu Yang3; 1Kanazawa University; 2University of Pennsylvania; 3University of Washington
    Paper-crafted 3D origami structures composed of the Tachi-Miura polyhedron (TMP) cells have attracted much attentions due to their unique properties such as negative Poisson’s ratio. The TMP unit cell can be utilized for cellular solids to tailor structures and mechanical properties depending on its geometrical design parameters by leveraging additive manufacturing. Here, we report on the compression behavior of additively-manufactured polymeric and metallic cellular solids composed of the TMP cells. Effects of geometrical design parameters on compression behavior of the TMP unit cell were investigated. Especially, shock-absorbing properties in the force-displacement relationship of the TMP cells controlled by geometrical design parameters were focused on for an application as shock-absorbing materials. The multi-TMP cellular solids were also designed and additively manufactured to tailor structures and mechanical properties. This work demonstrates the potential for designing new type of architected cellular solids based on the multi-TMP cells to obtain lightweight shock-absorbing materials.

P3-44: Directed Energy Deposition for Complex, Gradient Material Components: Melanie Lang1; 1Formalloy
    The current state-of-the-art methods for fabricating complex geometry components such as combustion chambers and heat exchangers typically require the use of forgings, which often possess lead times of 5-6 months. To achieve the end product, these forgings still require difficult post-processing with the required cooling channels, which adds to the total lead-time and increased the risk of errors. Additive manufacturing with directed energy deposition is an alternative, scalable, single-step method for producing complex, multi-material, dense or porous, near net-shape parts that have the potential to out-perform their traditionally manufactured equivalents with enhanced properties. Enhanced properties are achieved by employing gradient material strategies to create single components with multiple materials to increase corrosion resistance, wear resistance, strength, and improved thermal properties.

P3-45: Effect of Heat Treatments on Microstructural Transformations and Properties of Wire-arc Additively Manufactured Nickel Aluminum Bronze: Dharmendra Chalasani1; Kanwal Chadha1; G.D. Janaki Ram1; Mohsen Mohammadi1; 1Marine Additive Manufacturing Centre of Excellence
    The effect of three different heat treatments was investigated on the microstructural transformation and properties of nickel aluminum bronze Cu-9Al-4Fe-4Ni-1Mn fabricated through wire-arc additive manufacturing (WAAM). The heat treatments were performed at conditions of (a) 350oC/2 hours/air cooling (HT-1), (b) 550oC/4 hours/air cooling (HT-2), and (c) 675oC/6 hours/air cooling (HT-3). Microstructural evolution along the building direction was characterized with optical microscopy, scanning electron microscopy, and electron backscatter diffraction (EBSD). The microstructure of WAAM-NAB consists of κii (Fe3Al) and κiii (NiAl) phases in the interdendritic regions, and fine Fe-rich κiv particles in the Cu-matrix. HT-1 cycle had little impact on microstructural changes and mechanical properties. During HT-2 cycle, retained β was transformed to α+κ, and the morphology of κiii was changed from lamellar to a more globular. At 675oC, mechanical properties were enhanced due to the precipitation and significant increase in the volume fraction of κiv particles.

P3-47: Evaluation of Printability of Ecoefficient Cement Compositions Using Different Rheological Methods: Heitor Bernardo1; Estevão Laurito1; Alexandre Santos2; Valdecir Quarcioni2; Roberto Cesar Oliveira Romano1; Rafael Pileggi1; 1Escola Politécnica / Universidade de São Paulo; 2Instituto de Pesquisas Tecnológicas
    The civil construction sector is responsible for more than 50% of the extraction of raw materials, a value that is increasing due to the need for infrastructure and deficits of homes. Solutions that involve low environmental impacts and low risks to ergonomics, associated with high productivity, will be global trends. So, the use of 3D-additive manufacturing is growing up, because is fast and it is possible to produce high-performance components, with no need for molds, reducing the amount of waste. However, it is a common practice the use of compositions with large consumption of cement, representing considerable environmental impact due to the CO2-released. In this work, compositions with different cement consumption were evaluated using squeeze-flow and Benbow-Bridgwater methods, to comprehend the rheological parameters before the production of components using the 3D-print method. The results show that is possible to produce components with adequate fresh performance associated with low binder content.

P3-48: Geometric Model and Density Variation in Binder Jetting 3D-printed Concrete: Asif Ur Rehman1; Vincenzo Sglavo1; 1The University of Trento, Italy
    Additive manufacturing has the potential to revolutionize construction industry and reduce the structural environmental impact by one third. However, powder bed AM of Concrete is very challenging due to high sorptivity of concrete. Therefore, binder jetting of ordinary Portland cement and sand (25:75) powder bed has been studied with contriolled droplets of water-based binders. The study shows that due to the high absorptivity of water in sand and cement mixture the binder can be absorbed in much larger area than the desired geometry. A geometric model has been presented with the percentage increase in x, y and z direction with respect to the binder flow rate. Moreover, AM of concrete with pure water, water with 1% starch, water with 1 % PVA, and water with 2 % PVA have also been achieved. The change in mechanical properties and density has been presented.

P3-49: Influence of Part Positioning in Relation to the Build Plate on the Microstructure and Mechanical Properties of Electron Beam Melted Inconel 718 Parts: Tizian Arold1; Daniel Kotzem2; 1Universität Kassel Material science department; 2TU Dortmund University
    This work is going to show, that the microstructure and hence the mechanical properties of Inconel 718 processed by means of electron beam melting (EBM) are not only depending on the build height but also on the part positioning on the build plate. Therefore 30 identical samples were placed equidistant to each other on the build plate. Hardness tests, density measurements by means of µ-CT, as well as a comparison of target and obtained geometry were carried out. For microstructural investigation the microsections of the same sample height of selected samples were etched then examined by optical microscopy and scanning electron microscopy. The obtained insights then are correlated at first to the build height and second with the position on the build plate. The results revealed, that for mechanical properties the build plate can be separated into 3 areas which will be discussed.

P3-50: Investigation of Material Deformation Behavior under Dynamic Compressive Loading of Selective Laser Melted 316L Stainless Steel Samples: Md Salah Uddin1; Kristofer Kuelper1; Brahmananda Pramanik1; 1Montana Technological University
    Additive manufacturing (AM) revolutionizes the manufacturing industries for producing complex geometric parts with high accuracy and minimal production time. The current understanding of high strain rates material deformation behavior of AM parts under compressive loadings is limited. In this work, we performed high strain rates compressive loading test on stainless steel samples with Kolsky bar at room temperature. The test samples were fabricated by selective laser melting (SLM) process and the SLM is one of the AM methods. The samples had a layer thickness of 30 µm and five different layer orientations, such as 0⁰, 30⁰, 45⁰, 60⁰, and 90⁰ with three different global energy density (GED) values. The GED value of a sample is related to laser power, scan speed, hatch spacing, and layer thickness of the SLM process. In our study, we found the characteristic material deformation behavior depends on building layer orientations and the GED values.

P3-51: Investigation of Traditional vs. Designer Feedstock Powders for Additive Manufacturing: Jack Grubbs1; Kyle Tsaknopoulos1; Danielle Cote1; 1Worcester Polytechnic Institute
    Recent developments in powder-based additive manufacturing (AM) technology have prompted a need for designer feedstock material. To bridge the gap in processing and performance capabilities of traditional feedstock powder, various powders have been designed specifically for AM processes. Research was conducted to investigate whether these designer powders prove advantageous for AM processes. Narrow distributions in powder morphology, as well as enhanced powder properties, are indicative of optimal powder for AM. Given powder properties are strongly correlated to their internal microstructure, it is crucial to control the microstructure for desired powder performance. A powder's microstructural evolution can be finely controlled by thermal treatment, thus both heat treated and as-received powders were tested. The powder morphology was characterized using a size-and-shape particle analyzer, and the microstructure was analyzed using scanning electron microscopy, energy dispersive x-ray spectroscopy, and nanoindentation. Analysis was guided through the use of computation thermodynamic and kinetic models.

P3-52: Optimisation of Mixture Properties for 3D Printing of Geopolymer Concrete: Asif Ur Rehman1; Vincenzo Sglavo1; 1The University of Trento, Italy
    Construction industry is one of the key beneficiaries of 3D Printing due to the possibility of mass customization. Binder jetting of alkali activated geopolymer precursor is highly desirable for environmental-friendly use of this technology. The powder bed of the printer has been prepared using 8:1 sand to metakaolin ratio and the binder has been prepared by a mix of sodium silicate, sodium hydroxide and water mixture. Influence of the alkali activator (or more specifically the optimal binder mixture with sodium silicate, sodium hydroxide and water) on the mechanical properties of the concrete has been studied. The printed specimen was analyzed by 3-point bending tests and compression tests. The printed bars shown flexural strength and compression strength of 2.57 kN and 4.3 MPa, which is significantly higher than the ordinary Portland concrete (OPC) printed sample. Modulus of Rupture was also calculated based on the ASTM standard.

P3-53: Serial Sectioning 3D Characterization of Defects in Additive Manufacturing Powders and Components: Veeraraghavan Sundar1; Rachel Reed1; 1UES Inc
    Porosity plays a critical role in determining the mechanical behavior of additively and conventionally manufactured metal components. Defects such as voids decrease the strength and fatigue life of these components, which can limit the application of AM. Powder precursors have a critical effect on the outcome of AM processes. Serial sectioning involves removing material from a sample layer by layer – in a sense, the inverse of additive manufacturing, and is a practical and direct method of obtaining 3D microstructures, especially when automated. This study presents the evaluation of a variety of alloy powders (gas and water atomized) as well as techniques (directed energy, laser and electron beam powder bed fusion) for the evaluation of microstructure and defect distributions in AM processes, as well as and defect distribution.

P3-54: Smart Snow and Ice Prevention System Engineering and Manufacturing: Robert Burns1; Ryan Miller1; Zhen Liu1; 1Frostburg State University
    During the winter, there are many issues that arrive when it comes to transportation safety and pedestrian safety. The use of salt and other road treatments to prevent ice buildup have a negative impact on the environment and largely contribute to the corrosion process of automobiles and infrastructure elements. As for technologies, such as heated driveways and sidewalks, the installation process and operation costs are very high typically costing at a minimum $10000 for an average sized driveway. This project is designed to solve many of the problems that we could come across in the winter in a very cost effective and environmentally friendly way; our purposed product will provide a modular design with a smart temperature control option to reduce the cost of operation. This product will make winters less of a hassle as well as decrease the risk of injury's in the winters.

P3-56: Three-dimensional Quantitative Characterization on Binder-jet Printed Powder Systems: Chuyuan Zheng1; Amir Mostafaei2; Pierangeli Rodriguez1; Markus Chmielus1; Ian Nettleship1; 1University of Pittsburgh; 2Carnegie Mellon University
    Traditional quantitative stereology is usually taken on a 2D plane of a sectioned sample. The premise of such strategy is to assume the features measured are isotropic and distributed evenly throughout the sample, which is not the case in binder-jet printed systems. Also, limitations of field measurements and the incompetency of measuring topological parameters hinder the discovery of process-structure relationship of such systems. In this study microCT was used to obtain 3D microstructures of as-printed and consolidated materials. Density variations through sections revealed the periodic interlayer defects introduced during printing, and 3D topological parameters was reported to describe the microstructure evolution during sintering. The utilization of microCT demonstrated the capability of supervising the microstructure evolution through the entire printing-consolidation process, and the exponentially increased information density in 3D datasets opened up possibilities of process-structure-property relationship mining using computer vision methods.

P3-57: Unique Microstructure and Phase Transformation Behavior of High Carbon Tool Steel Layers Produced by Direct Energy Deposition Method: Jongbae Jeon1; Wookjin Lee1; Sunmi Shin1; Byungjun Kim1; 1Korea Institute of Industrial Technology
    Direct energy deposition (DED) method, one of the most widely-used AM methods, has potential to be used for repairing and surface modification of molds and broken parts, and recent studies carry out on the DED process of tool steels. However, microstructure evolution and phase transformation behavior of the deposited tool steel layers are dramatically different from bulk metals produced by conventional casting and heat treatment processes. The present study thus investigated the phase transformation of the deposited layers fabricated by DED process. The tool steel powder has a composition of M4-grade and was deposited on D2-grade substrate. It was found that in spite of rapid cooling rate, considerable amount of retained austenite was observed in room temperature, which is rarely found in the bulk M4-grade after conventional quenching process. Here we proposed underlying mechanism of this unique phase transformation behavior in the present tool steels deposited by DED process.