Browsing by Subject "functionally graded materials"
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Item Additive Manufacturing of Cu on 316L Stainless Steel via Inconel 718 Intermediate Layers(University of Texas at Austin, 2021) Zhang, Xinchang; Pan, Tan; Chen, Yitao; Liou, FrankJoining of dissimilar materials is becoming increasingly prevalent to combine differing material properties to enhance product design flexibility and performance. In this study, pure copper was built on 316L stainless steel (SS316L) by laser-based additive manufacturing technology in which copper was deposited layer-by-layer on SS316L with Inconel 718 intermediate layers. The goal is to fabricate multi-metallic structures with improved thermal conductivity. The direct joining of Cu on SS316L would result in porosities at the interface and the consequent poor mechanical properties, which could be addressed by Inconel 718 intermediate layers. The microstructure, chemical composition, tensile properties, and micro-hardness were characterized in the dissimilar materials using scanning electron microscopy, energy dispersive spectroscopy, tensile test with digital image correlation technique, and hardness tester. Results confirm excellent bonding when Inconel 718 intermediate layers are introduced.Item Additive Manufacturing of Metal Functionally Graded Materials: A Review(University of Texas at Austin, 2018) Chen, Yitao; Liou, FrankFunctionally graded materials (FGMs) have attracted a lot of research interest due to their gradual variation in material properties that result from the non-homogeneous composition or structure. Metal FGMs have been widely researched in recent years, and additive manufacturing has become one of the most important approaches to fabricate metal FGMs. The aim of this paper is to review the research progress in metal FGMs by additive manufacturing. It will first introduce the unique properties and the advantages of FGMs. Then, typical recent findings in research and development of two major types of metal additive manufacturing methods, namely laser metal deposition (LMD) and selective laser melting (SLM), for manufacturing different types of metal FGMs will be discussed. Finally, the major technical concerns in additive manufacturing of metal FGMs which are closely related to mechanical properties, and industrial applications of metal FGMs will be covered.Item Characterizing Material Transition for Functionally Graded Material Using Big Area Additive Manufacturing(University of Texas at Austin, 2016) Sudbury, Zeke; Duty, Chad; Kunc, Vlastimil; Kishore, Vidya; Ajinjeru, Christine; Failla, Jordan; Lindahl, JohnThis study examines functionally graded materials (FGM) on a polymer based large scale additive manufacturing system. FGM utilizes a less expensive material with sub-optimal mechanical properties for the majority of the part, and uses more expensive higher performance material in selected areas. This process aims to optimize cost with weight and mechanical performance. FGM is already used a variety of industries, but is not common place in additive manufacturing, specifically large scale additive manufacturing like Cincinnati Incorporated’s Big Area Additive Manufacturing (BAAM). BAAM can use a variety of plastic injection molding and extrusion style polymer pellets, which allows it to use both commodity materials and high performance engineering polymers. This study is an initial assessment of FGM using glass fiber reinforced ABS and carbon fiber reinforced ABS, and characterizes the performance of a density gradient shape function to characterize the blending of materials.Item Converting a CAD Model into a Manufacturing Model for the Components Made of a Multiphase Perfect Material(2004-08-04) Zhu, Feng; Chen, Ke-Zhang; Feng, Xin-AnTo manufacture the component made of a multiphase perfect material (including homogeneous and multi heterogeneous materials), it CAD model should be processed and converted into layered manufacturing model for further transformation of numerical control (NC) coding. This paper develops its detailed approaches and corresponding software. The process planning is made first and includes: (1) determining the build orientation of the component; and (2) slicing the component into layers adaptively according to different material regions since different materials have different optimal layer thickness for manufacturing. After the process planning, the layered manufacturing models with necessary information, including fabrication sequence and material information of each layer, are fully generated.Item Development of Functionally Graded Material Capabilities in Large-scale Extrusion Deposition Additive Manufacturing(University of Texas at Austin, 2019) Brackett, James; Yan, Yongzhe; Cauthen, Dakota; Kishore, Vidya; Lindahl, John; Smith, Tyler; Ning, Haibin; Kunc, Vlastamil; Duty, ChadAdditive manufacturing’s (AM) layer-by-layer nature is well-suited to the production of Functionally Graded Materials (FGM) with discrete material boundaries. Extrusion deposition is especially advantageous since multiple nozzles easily accommodate the inclusion of additional materials. However, discrete interfaces and sudden composition changes can limit the functionality of a printed part through inherently weak bonding. Furthermore, same-layer transitions are not only difficult to execute, but also further amplify structural weaknesses by creating multiple discrete interfaces. Therefore, successfully implementing a blended, continuous gradient will greatly advance the applicability of FGM in additive manufacturing. The pellet-fed nature and integrated screw design of the Big Area Additive Manufacturing system enables material mixing needed for development of this capability. Using constituent content analysis, this study evaluates the transition behavior of a neat ABS/CF-ABS material pair and characterizes the repeatability of the mixing and printing process, which ultimately leads to control of site-specific material deposition and properties.Item Effect of Energy Density on the Consolidation Mechanism and Microstructural Evolution of Laser Cladded Functionally-Graded Composite Ti-Al System(University of Texas at Austin, 2018) Olakanmi, E.O.; Sepako, M.; Morake, J.; Kutua, S.; Hoosain, S.E.; Pityana, S.L.The engagement of additive manufacturing (AM) technology in developing intermetallic coatings involves additional heat treatment with a view to obtaining desirable microstructure and mechanical properties. This eventually increases the lead time and the manufacturing cost. To address these challenges, this study explores the fabrication of gradient and laminar structures of titanium aluminide (Ti-Al) composite coatings deposited on Ti-6Al-4V substrate via a single step laser cladding (LC). The alterations in microstructural properties, chemical composition and phase analysis of the coatings reinforced with TiC were investigated as a function of laser energy density. Evaluation of the deposited samples reveals that FGM composite clads were fabricated from Ti-Al blended with TiC when LED was set at 17.50 J/mm2 . At the selected LED, a thermo-positive reaction between the constituents’ materials was induced and it resulted in the formation of intermetallic compounds (e.g. Ti2AlC, 𝛾𝛾 and 𝛼𝛼2 matrix phases) with a microhardness more than that of the substrate (Ti-6Al-4V alloy). This study provides new insights on the selection of process parameters for the coating manufacturers while employing low cost- and time-effective LC process for fabricating functional graded Ti-Al coatings.Item Expanding Material Property Space Maps with Functionally Graded Materials for Large Scale Additive Manufacturing(University of Texas at Austin, 2017) Sudbury, Zeke; Duty, Chad; Kunc, VlastimilBig Area Additive Manufacturing (BAAM) is a large scale extrusion-based print system that exceeds the throughput of conventional printers by five hundred times. In addition, BAAM uses pelletized feedstocks, which allows for site-specific definition of material composition and provides an unprecedented variety of material options. This study applies Ashby’s concept of a material property space map to a variety of materials suitable for printing on BAAM. Ashby maps plot the performance of various materials across multiple parameters (such as strength, density, stiffness, etc) allowing for direct comparison of non-dimensional performance criteria. This study uses Ashby maps to identify opportunities for the use of functionally graded materials on BAAM to achieve structural performance not yet available with conventional printers and homogeneous materials.Item Fabricating Functionally Graded Materials by Ceramic On-Demand Extrusion with Dynamic Mixing(University of Texas at Austin, 2018) Li, Wenbin; Martin, Austin J.; Kroehler, Benjamin; Henderson, Alexander; Huang, Tieshu; Watts, Jeremy; Hilmas, Gregory E.; Leu, Ming C.Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. Presented in this paper is a further development of this process focusing on fabrication of functionally graded materials (FGM). A dynamic mixing mechanism was developed for mixing constituent ceramic pastes, and an extrusion control scheme was developed for fabricating specimens with desired material compositions graded in real time. FGM specimens with compositions graded between Al2O3 and ZrO2 were fabricated and ultimately densified by sintering to validate the effectiveness of the CODE process for FGM fabrication. Energy dispersive spectroscopy (EDS) was used to compare final compositions to the original material designs. The specimen’s hardness at different locations along the gradients was examined by micro-indentation tests. The dimensions of sintered specimens were measured, and the effects of material composition gradients on the distortions of sintered FGM specimens were analyzed.Item Functionally Graded Materials by Laser Metal Deposition(University of Texas at Austin, 2009-09) Pulugurtha, Syamala R.; Newkirk, Joseph; Liou, Frank; Chou, Hsin-NanFabrication of functionally graded materials (FGMs) by laser metal deposition (LMD) has the potential to offer solutions to key engineering problems over the traditional metal-working techniques. But the issues that need to be addressed while building FGMs are intermixing in the layers and cracking due to the residual stresses. This paper is to present the study of the effect of process parameters (laser power and travel speed) on the degree of dilution between the substrate (or, previous layer) and powder material for few metallurgical systems.Item Investigation of the Scan Strategy and Property of 316L Stainless Steel-Inconel 718 Functionally Graded Materials Fabricated by Selective Laser Sintering(University of Texas at Austin, 2015) Zhou, Y.; Zhou, X.; Teng, Q.; Wei, Q.S.; Shi, Y.S.316L stainless steel and Inconel 718 alloy functionally graded materials were fabricated by selective laser melting with a novel approach which combined powder-bed with powder-feed pattern. Two different scanning strategies have been used to form the steel/Ni FGMs. The interfacial characteristics were analyzed by scanning electron microscopy and energy dispersive spectroscopy. Quantitative evidence of good bonding at the interface was obtained from the tensile and shear tests of the steel/Ni FGMs.Item Manufacturing of Complex Parts with Continuous Functionally Graded Materials (FGM)(University of Texas at Austin, 2011-08-17) Hascoet, J.Y.; Muller, P.; Mognol, P.One of major evolutions of the additive manufacturing is the ability to produce parts with functionally graded materials (FGM). However, manufacturing of these parts is limited to discrete or nearly continuous FGM on samples. To achieve this, it is necessary to have a global control of processes and to develop methodologies to help designers and manufacturers. A methodology to produce morphologically complex parts is proposed in this paper. It consists in classifying all typologies of bi-materials gradients with mathematical description. Each typology of gradient is associating with manufacturing strategies in order to choose slicing and path strategies. Afterwards, mathematical data are used to have a global control of a process. This paper presents the principle of this methodology and the mathematical models which are chosen to describe part and manufacturing.Item Material Property Changes in Custom-Designed Digital Composite Structures Due to Voxel Size(University of Texas at Austin, 2018) Kaweesa, Dorcas V.; Meisel, Nicholas A.Advances in additive manufacturing enable fabrication of complex structures using functionally graded materials (FGMs) at a voxel level. Prior to developing voxel-based FGM designs using compatible dithering approaches, it is essential to first understand the basic principles of voxel-based digital composite designs. While several research studies exist regarding different representations of composition in voxel-based solid models, there is no extensive research on the material properties of voxel-based digital composite structures. This paper bridges this gap by investigating custom voxel-based designs of digital composite structures. The objective is to determine how the material properties of such structures are impacted by different voxel sizes using the material jetting process. In addition to the material properties, computational time taken to process different voxel sizes is analyzed. By doing so, we gain a better understanding of the relationship between material composition and voxel size in digital composite structures.Item Process Planning and Control for Functionally Graded Material Fabrication Using Freeze-Form Extrusion Fabrication(University of Texas at Austin, 2011-08-17) Deuser, Brad; Tang, Lie; Geldmeiner, Jeff; Landers, Robert G.; Leu, Ming C.Using multiple materials in additive manufacturing technologies is critical for building parts with functionally gradient geometries. In order to achieve a desired material gradient, an advanced process planning and control system is required. This paper details the development of a process planning method and control system for functionally graded material fabrication using a triple extruder Freeze-form Extrusion Fabrication (FEF) system including motion code generation, extruder dynamic modeling and control, and composition gradient control. The effect that extruding multiple materials from a single orifice via static mixing has on the time delay of the resulting mixture is taken into account for path planning, and this factor is incorporated into integrating motion codes with extrusion commands. The effectiveness of the proposed system is demonstrated by fabricating three-dimensional parts with desired gradient compositions using multiple materials.Item SFF-Oriented Modeling and Process Planning of Functionally Graded Materials Using a Novel Equal Distance Offset Approach(2004) Xu, Anping; Shaw, Leon L.This paper deals with the modeling and process planning of solid freeform fabrication (SFF) of 3D functionally graded materials (FGMs). A novel approach of representation and process planning of FGMs, termed as equal distance offset (EDO), is developed. In EDO, a neutral arbitrary 3D CAD model is adaptively sliced into a series of 2D layers. Within each layer, 2D material gradients are designed and represented via dividing the 2D shape into several sub-regions enclosed by iso-composition contours. If needed, the material composition gradient within each of sub-regions can be further determined by applying the equal distance offset algorithm to each sub-region. Using this approach, an arbitrary-shaped 3D FGM object with linear or non-linear composition gradients can be represented and fabricated via suitable SFF machines.