Materials Science and Engineering Commons^™

Polyestyrene And Low Density Polyethylene Oregano´S Essential Oil Functionalization For Possible Antimicrobial Active Packaging Applications, Edgar Díaz-Acosta, Claudia Rodríguez-González, Laura Valencia-Gómez, Santos Adriana Martel-Estrada, Maria Hernández-González, Hortensia Reyes-Blas, Imelda Olivas Armendáriz 1761524

Journal of Applied Packaging Research

Low density polyethylene (LDPE) and polystyrene (PS) samples were functionalized with oregano´s essential oil (OEO) for possible antimicrobial packing applications. Different concentrations of OEO were used (0.5-1.5 % v/v). Polymers were UV light irradiated during 60 min to improve the OEO adhesion through the polar groups (COOH, OH or COO-) generation on their surface. The effect of OEO different concentration on their antimicrobial activity, mechanical properties and cytotoxicity of the functionalized polymers were analyzed. All functionalized samples showed antimicrobial activity against Gram positive and Gram negative bacteria and this activity increased with OEO concentration. The addition of OEO did not …

Experimental Tests And Numerical Simulations For Failure Investigation On Corrugated Boxes Used On Household Appliance Packaging, Diego Fernandes Rodrigues, José Carlos Pereira

Journal of Applied Packaging Research

Packages made of corrugated paper are fundamental to the protection, transportation and handling of the appliance product market. During the storage and sales stages of a product, the package must resist compressive loads in different directions beyond moderate impacts. In this context, the objective of this work is to develop and implement a post-processor that allows the simultaneous analysis of two of the most common failure modes of packages made of corrugated paper: failure due to tensile or compressive stress limit, and failure due to local buckling, when the buckling of the faces of the corrugated paper between two peaks …

Nanoflower-Like Bi2moo6/Ag3po4 In Water Treatment, Xavier Morgan-Lange, Jaeyun Moon, Kaleab Ayalew

McNair Poster Presentations

• Environmental issues continue to intensify causing natural resources such as clean water to become increasingly scarce while demand only continues to grow. • Some of the most effective measures taken appear to be bioremediation tactics and their synthetic counterparts. • A critical area of interest are semi-conducting photocatalytic nanomaterials that take advantage of the photo-electric effect and use the introduction of ultra violet (UV) and visible light to induce oxidation and reduction reaction in p-type semiconductors. This results in the decomposition of certain pollutants and/or deactivates certain microbes in water. • These materials have the potential to operate using …

Approaches To Open Source 3-D Printable Probe Positioners And Micromanipulators For Probe Stations, Iiro Hietanen, Ismo T. S. Heikkinen, Hele Savin, Joshua M. Pearce

Department of Materials Science and Engineering Publications

Three types of highly-customizable open source probe positioning systems are evaluated: (a) mostly 3-D printed, (b) partially printed using OpenBeam kinematic constraints, and (c) a 3-level stack of low-cost commercial single axis micropositioners and some printed parts. All systems use digital distributed manufacturing to enable bespoke features, which can be fabricated with RepRap-class 3-D printer and easily accessible components. They are all flexible in material choice for custom components. The micropositioners can be set up for left-right use and flat or recessed configurations using either mechanical or magnetic mounting. All systems use a manual probe holder that can be customized …

Electron Paramagnetic Resonance And Optical Absorption Study Of Acceptors In Cdsip2 Crystals, Elizabeth M. Scherrer, Larry E. Halliburton, Eric M. Golden, Kevin T. Zawilski, Peter G. Schunemann, F. Kenneth Hopkins, Kent L. Averett, Nancy C. Giles

Faculty Publications

Cadmium silicon diphosphide (CdSiP₂) is a nonlinear material often used in optical parametric oscillators (OPOs) to produce tunable laser output in the mid-infrared. Absorption bands associated with donors and acceptors may overlap the pump wavelength and adversely affect the performance of these OPOs. In the present investigation, electron paramagnetic resonance (EPR) is used to identify two unintentionally present acceptors in large CdSiP₂ crystals. These are an intrinsic silicon-on-phosphorus antisite and a copper impurity substituting for cadmium. When exposed to 633 µm laser light at temperatures near or below 80 K, they convert to their neutral paramagnetic charge …

Self-Cleaning Nanocomposite Membranes With Phosphorene-Based Pore Fillers For Water Treatment, Joyner Eke, Katherine Elder, Isabel Escobar

Chemical and Materials Engineering Faculty Publications

Phosphorene is a two-dimensional material exfoliated from bulk phosphorus and it possesses a band gap. Specifically, relevant to the field of membrane science, the band gap of phosphorene provides it with potential photocatalytic properties, which could be explored in making reactive membranes that can self-clean. The goal of this study was to develop an innovative and robust membrane that is able to control and reverse fouling with minimal changes in membrane performance. To this end, for the first time, membranes have been embedded with phosphorene. Membrane modification was verified by the presence of phosphorus on membranes, along with changes in …

Coal With Carbon Capture And Sequestration Is Not As Land Use Efficient As Solar Photovoltaic Technology For Climate Neutral Electricity Production, James Gunnar Groesbeck, Joshua M. Pearce

Michigan Tech Publications, Part 1

Avoiding climate destabilization caused by greenhouse gas (GHG) emissions, requires climate-neutral electricity sources. It has been proposed that the GHG emissions from coal-fired power plants can be offset by carbon capture and sequestration or bio-sequestration. However, solar photovoltaic (PV) technology has recently declined so far in costs it now offers both technical and economic potential to offset all of coal-fired electricity use. PV only emits GHGs during fabrication and not during use. To determine which technical solution to climate-neutral electricity generation should be preferred, this study aggregates and synthesizes life cycle analysis studies for exergy, GHG emissions and land transformation …

Gold-Catalyzed Conversion Of Lignin To Low Molecular Weight Aromatics, Yang Song, Justin K. Mobley, Ali Hussain Motagamwala, Mark Isaacs, James E. Dumesic, John Ralph, Adam F. Lee, Karen Wilson, Mark Crocker

Chemistry Faculty Publications

A heterogeneous catalyst system, employing Au nanoparticles (NPs) and Li–Al (1 : 2) layered double hydroxide (LDH) as support, showed excellent activity in aerobic oxidation of the benzylic alcohol group in β-O-4 linked lignin model dimers to the corresponding carbonyl products using molecular oxygen under atmospheric pressure. The synergistic effect between Au NPs and the basic Li–Al LDH support induces further reaction of the oxidized model compounds, facilitating facile cleavage of the β-O-4 linkage. Extension to oxidation of γ-valerolactone (GVL) extracted lignin and kraft lignin using Au/Li–Al LDH under similar conditions produced a range of aromatic monomers in high yield. …

Belt-Driven Open Source Circuit Mill Using Low-Cost 3-D Printer Components, Shane W. Oberloier, Joshua M. Pearce

Department of Materials Science and Engineering Publications

Barriers to inventing electronic devices involve challenges of iterating electronic designs due to long lead times for professional circuit board milling or high costs of commercial milling machines. To overcome these barriers, this study provides open source (OS) designs for a low-cost circuit milling machine. First, design modifications for mechanical and electrical subsystems of the OS Distributed 3-D (D3D) Robotics prototyping system are provided. Next, Copper Carve, an OS custom graphical user interface, is developed to enable circuit board milling by implementing backlash and substrate distortion compensation. The performance of the OS D3D circuit mill is then quantified and validated …

Economic Advantages Of Dry-Etched Black Silicon In Passivated Emitter Rear Cell (Perc) Photovoltaic Manufacturing, Chiara Modanese, Hannu S. Laine, Toni P. Pasanen, Hele Savin, Joshua M. Pearce

Department of Materials Science and Engineering Publications

Industrial Czochralski silicon (Cz-Si) photovoltaic (PV) efficiencies have routinely reached >20% with the passivated emitter rear cell (PERC) design. Nanostructuring silicon (black-Si) by dry-etching decreases surface reflectance, allows diamond saw wafering, enhances metal gettering, and may prevent power conversion efficiency degradation under light exposure. Black-Si allows a potential for >20% PERC cells using cheaper multicrystalline silicon (mc-Si) materials, although dry-etching is widely considered too expensive for industrial application. This study analyzes this economic potential by comparing costs of standard texturized Cz-Si and black mc-Si PERC cells. Manufacturing sequences are divided into steps, and costs per unit power are individually calculated …

Comparative Investigation Of Thermal And Structural Behavior In Renewably Sourced Composite Films Of Even-Even Nylons (610 And 1010) With Silk Fibroin, Kayla Calloway, Ye Xue, Vincent Altimari, Guoxiang Jiang, Xiao Hu

College of Science & Mathematics Departmental Research

As the average life expectancy continues to increase, so does the need for resorbable materials designed to treat, augment, or replace components and functions of the body. Naturally occurring biopolymers such as silks are already attractive candidates due to natural abundance and high biocompatibility accompanied by physical properties which are easily modulated through blending with another polymer. In this paper, the authors report on the fabrication of biocomposite materials made from binary blends of Bombyx mori silk fibroin (SF) protein and renewably sourced low molecular weight nylon 610 and high molecular weight nylon 1010. Films were characterized using scanning electron …

Capturing The Competing Influence Of Thermal And Mechanical Loads On The Strain Of Turbine Blade Coatings Via High Energy X-Rays, Albert Manero, Kevin Knipe, Janine Wischek, Carla Meid, John Okasinski, Jonathan Almer, Anette M. Karlsson, Marion Bartsch, Seetha Raghavan

Mechanical Engineering Faculty Publications

This paper presents findings of synchrotron diffraction measurements on tubular specimens with a thermal barrier coating (TBC) system applied by electron beam physical vapor deposition (EB-PVD), having a thermally grown oxide (TGO) layer due to aging in hot air. The diffraction measurements were in situ while applying a thermal cycle with high temperature holds at 1000 °C and varying internal air cooling mass flow and mechanical load. It was observed that, during high temperature holds at 1000 °C, the TGO strain approached zero if no mechanical load or internal cooling was applied. When applying a mechanical load, the TGO in-plane …

Boron-Implanted Silicon Substrates For Physical Adsorption Of Dna Origami, Sadao Takabayashi, Shohei Kotani, Juan Flores-Estrada, Elijah Spears, Jennifer E. Padilla, Lizandra C. Godwin, Elton Graugnard, Wan Kuang, William L. Hughes

Materials Science and Engineering Faculty Publications and Presentations

DNA nanostructures routinely self-assemble with sub-10 nm feature sizes. This capability has created industry interest in using DNA as a lithographic mask, yet with few exceptions, solution-based deposition of DNA nanostructures has remained primarily academic to date. En route to controlled adsorption of DNA patterns onto manufactured substrates, deposition and placement of DNA origami has been demonstrated on chemically functionalized silicon substrates. While compelling, chemical functionalization adds fabrication complexity that limits mask efficiency and hence industry adoption. As an alternative, we developed an ion implantation process that tailors the surface potential of silicon substrates to facilitate adsorption of DNA nanostructures …

Non-Destructive Characterization Of Rotated Uniaxial Anisotropic Materials, Alexander G. Knisely

Theses and Dissertations

Electromagnetic material characterization of anisotropic media requires measurement diversity, minimal measurement uncertainty and insight into sample symmetry. Additionally, non-destructive characterization techniques are valued over legacy measurement techniques because a destructive approach requires sample preparation to execute a measurement. A Single Port Waveguide Probe (SPWP) non-destructive material characterization technique is proposed to accommodate measuring a metal backed, known thickness, rotated uniaxial anisotropic material. A rotated uniaxial sample possesses unique transverse constitutive components and a longitudinal constitutive component which is the same as one of the transverse values. The SPWP consists of a rectangular waveguide aperture cut in the center of a …

The Design, Test And Evaluation Of A Sensing System For Process Analytical Technology (Pat), Trevor Murphy

Theses

Increased globalisation and competitiveness has given rise to a more dynamic and diverse global market that has begun to place incredible strain on manufacturing supply chains. Conventional manufacturing methods such as the batch manufacturing methods employed largely by the materials processing industries i.e. pharmaceuticals, polymers and magnesium processing plants are ill-suited to cope with the demands of today. As products evolve with technological advancements they become more complex to produce and require alternative approaches to manufacturing to ensure product quality while reducing costs and increasing manufacturing efficiencies.

A potential solution to the growing demands on today’s supply chain is process …

Cellulose-Derived Glycosaminoglycan Mimetic For Use In Cartilage Tissue Engineering Strategies, Roseline Dominic Menezes

Dissertations

Articular cartilage has limited healing and self-repair capability due to the absence of vasculature, lymphatic vessels, and nerves. Damage to articular cartilage becomes irreversible leading to formation of osteoarthritis that could severely degrade a person's quality of life. Approximately, 5-10% of cartilage tissue is made up of glycosaminoglycans (GAG), which sequester growth factors as well as provide structural integrity to the native cartilage tissue. Transforming growth factor-beta3 (TGF-β3) is an important growth factor for inducing chondrogenesis in mesenchymal stem cells (MSCs). Bioavailability of TGF-β3 plays a critical role in cartilage repair both in vitro and in vivo. This study evaluates …

An Aqueous All-Metal Oxide Asymmetric Supercapacitor With High Gravimetric And Volumetric Energy Densities, Xin Jing, Xu Zhang, Wei Wang, Jun-Wei Lang

Journal of Electrochemistry

Only with both high gravimetric and high volumetric energy densities, can supercapacitors find more extensive applications.In this paper, by making good use of the interesting nanostructures and the high packing densities of RuO₂ (nanoshpheres,1.69 g·cm^-3) and Co-Ni oxide (nanoflakes, 2.14 g·cm^-3), the RuO₂//KOH//Co-Ni oxide all-metal oxide asymmetric supercapacitors with high performance were successfully fabricated, which led to the maximum specific capacitance of 217.5 F·g^-1 (412.3 F·cm^-3) and specific energy density of 61.8 Wh·kg^-1 (121 Wh·L^-1) in a cell voltage between 0 and 1.5 V in KOH electrolyte. …

Preparation And Characterization Of Self-Supporting Flexible Nitrogen-Doped Carbon Fabric Electrodes, Bo Yang, Zhi-Hang Jin, Ya-Ping Zhao, Zai-Sheng Cai

Journal of Electrochemistry

With the wide applications of intelligent wearable devices in various fields, developing a new generation of flexible energy storage devices has become a major challenge for the current technology. As a wide application of wearable flexible substrate, cotton fabric has the advantages over low price, non-toxic and environmental friendly, but the poor conductivity becomes a major problem limiting its development. As a nitrogen-containing conducting polymer, polypyrrole is traditionally used as electrode materials, but poor mechanical performance and cycle stability severely limit its application in electrode materials. In this article, a self-supporting flexible nitrogen-doped carbon fabric electrode was prepared by in …

Hybrid Battery-Capacitor System Based On Liti5O12 Anode And Ptpan Cathode, Xiu-Li Su, Xiao-Li Dong, Yao Liu, Yong-Gang Wang, Ai-Shui Yu

Journal of Electrochemistry

Owing to its high safe, high rate and long life characteristics, lithium titanate (Li₄Ti₅O₁₂) anode material has attracted extensive attention in recent years, and many efforts are being made to develop the Li₄Ti₅O₁₂ based high performance hybrid supercapacitors and Li-ion batteries. Herein, we prepared the organic cathode material polytriphenylamine (PTPAn) through chemical oxidation and polymerization of triphenylamine (TPAn), and investigated its charge storage mechanism and electrode kinetics withthe typical electrochemical methods in an organic electrolyte. It was demonstrated that the PTPAn exhibited the reversible capacity of 85 mA·g^{-1 …}

Assemblies And Properties Of Asymmetric Supercapacitors Based On Wo3/Carbon Cloth, Wen-Ke Shao, Lei Zhao, Chao Liu, Yan-Ying Dong, Yuan-Jie Zhu, Qiu-Fan Wang

Journal of Electrochemistry

The demand for a new generation of flexible, portable, and high-capacity power sources increases rapidly with the development of advanced wearable electronic devices. One dimensional (1D) nanowires structures have been demonstrated as one of the most ideal electrode materials in energy storage systems due to their advantages in both micorstructures and their high surface areas. Here we report a simple process for large-scale fabrication of self-standing composite film electrodes composed of WO₃ nanorods on carbon cloth. In order to improve the energy density of supercapacitor, we assembled an asymmetric supercapacitor using WO₃ nanorods and activated carbon cloth as …

Complex Coordination Silver Electrocrystallization Mechanism On Glassy Carbon Electrode Surface, Shuai-Shuai Huang, Cheng Liu, Lei Jin, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min. Zhou

Journal of Electrochemistry

Cyclic voltammetry and potential step methods were successfully used to study the electrochemical crystallization mechanism of silver deposition on glassy carbon electrode (GCE) in the practical cyanide-free silver plating electrolyte containing composite complexing agents. Scharifker-Hill (SH) theory was used to fitting the experimental data. The results showed that the electrodeposition of silver is a diffusion controlled irreversible electrode process according to three-dimensional instantaneous nucleation mechanism. When the step potential shifted from -750 mV to -825 mV, the peak deposition current Im was increased, while the induced nucleation time tm shortened. The calculated kinetic parameters showed that the diffusion coefficient (D) …

Electrochemical Performances Of Neodymium Doped Lead Dioxide Composite Anode, Hong-Hui Wang, Ming-Jie Ma, Jie Feng, Huang-Ya Kang, Wen-Jie Huang

Journal of Electrochemistry

Neodymium (Nd) doped titanium (Ti)-based lead dioxide (PbO₂) composite anode was prepared by electrodeposition. The surface morphologies and crystal structures of the as-prepared anodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique, respectively. The electrochemical performances of PbO₂-Nd anode were studied by electrochemical impedance spectroscopy, linear sweep voltammetry and cyclic voltammetry. Additionally, the electrocatalytic activity and durability of PbO₂-Nd anode were investigated through the degradation of simulative refractory organic wastewater of phenol. The results showed that Nd doping made the PbO₂ anode surface structure dense and uniform with smaller …

Preparations Of Nano-Manganite Loaded Titanium Electocatalytic Membrane Electrode For Phenolic Wastewater Treatment, Le Li, Hong Wang, Rong-Hua Ma, Hong-Sen Hui, Xiao-Ping Liang, Jian-Xin Li

Journal of Electrochemistry

Nano-manganese oxide loaded on titanium electrocatalytic membrane electrodes (nano-MnO_x/Ti) were synthesized bysol-gel method using porous Ti membrane as a substrate and the manganese acetate as a raw material without releasing NO_x. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Field-emission scanning electron microscopy (FESEM) were employed to characterize crystal form, valence state and surface morphology of nano-MnO_x, respectively. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) were used to investigate the electrochemical properties of nano-MnO_x electrode. The results indicated that the MnO_x catalysts consisted of γ-MnO₂ and Mn_{2 …}

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

Influences Of Na-Mn Ratio On Electrochemical Performances And Intercalation-Deintercalation Processes Of Sodium Ion In NaXMno2, Yong-Chun Xie, Cheng Wang, Fang Jiang, Yang Yang, Jing Su, Yun-Fei Long, Yan-Xuan Wen

Journal of Electrochemistry

In this work, Na_xMnO₂ was synthesized by a solid-state reaction. The influences of Na:Mn ratio on the structure, morphology and electrochemical performance, and sodium ion intercalation/deintercalation processes were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge test. The prepared Na_xMnO₂ was mainly composed of Na_0.7MnO₂ and Na_0.91MnO₂, and the content of Na_0.91MnO₂ increased with the increase of Na:Mn ratio. However, the activation energy values of surface membrane diffusion, interfacial electrochemical reaction and …

Electrochemical Preparation And Photo-Electro Catalytic Properties Of Flexible Znni/Al-Ldhs/Carbon Fibers Composite, Jing-Jing Tian, Tao Chen, Xing-Chen Bao, Meng-Xu Gao, Ye-Xiao Yu, Si-Yao Peng, Guan-Ping Jin

Journal of Electrochemistry

In this work, a promising flexible composite consisting of zinc (Zn), nickel (Ni) and aluminum (Al) layered double hydroxide coated carbon fibers (ZnNi/Al-LDHs/CFs) was prepared by electrochemical method with convenient recovery and separation. The structures, morphologies, and photo-electro catalytic properties of ZnNi/Al-LDHs/CFs were characterized by X-ray diffraction, infrared spectroscopy, field emission scanning electron microscopy, inductively coupled plasma atomic emission spectrometry and electrochemical impedance spectroscopy techniques. The excellent photo-electro bifunctional catalytic properties were obtained with the ZnNi/Al-LDHs/CFs composite as compared to that of Zn/Al-LDHs/CFs (photo catalyst) or Ni/Al-LDHs/CFs (electrocatalyst) alone, which could be used in the electro-catalytic oxidations of methanol and …

Structural Evolution Of Molybdenum Disulfide Prepared By Atomic Layer Deposition For Realization Of Large Scale Films In Microelectronic Applications, Steven Letourneau, Elton Graugnard

Materials Science and Engineering Faculty Publications and Presentations

Molybdenum disulfide (MoS₂) films are attractive materials for electronic and optoelectronic devices, but the temperatures used in the chemical vapor deposition (CVD) of these materials are too high for device integration. Recently, a low-temperature atomic layer deposition (ALD) process was demonstrated for growth of MoS₂ films at 200 °C using MoF₆ and H₂S. However, the as-deposited films were amorphous and required annealing to obtain the desired layered structure. The MoS₂ films were sulfur-deficient; however, after annealing the crystallinity improved. To study the structure of these films and the process by which they crystallize, …

Electropolishing Valve Metals With A Sulfuric Acid-Methanol Electrolyte At Low Temperature, Pete Barnes, Andreas Savva, Kiev Dixon, Hailey Bull, Laura Rill, Devan Karsann, Sterling Croft, Jesse Schimpf, Hui Xiong

Materials Science and Engineering Faculty Publications and Presentations

This study reports the electropolishing Ti and Nb metals using a fluoride-free electrolyte of sulfuric acid and methanol at low temperature (-70°C) without prior treatment. A fluoride-free electrolyte provides a less hazardous and more environmentally friendly option for electropolishing procedure. Experimental studies are presented on electropolishing with sulfuric acid electrolyte, which provides high quality macro- and micro-smoothing of the metal surfaces. Optimal conditions yielded leveling and brightening of the surface of Ti and Nb metals beyond that of the currently utilized electropolishing procedures with fluoride-containing electrolytes. The root mean squared roughness (R_q) from atomic force microscopy (AFM) …

Recyclability Of 304l Stainless Steel In The Selective Laser Melting Process, Austin T. Sutton, Caitlin S. Kriewall, Ming-Chuan Leu, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

During part fabrication by selective laser melting (SLM), a powder-bed fusion process in Additive Manufacturing (AM), a large amount of energy is input from the laser into the melt pool, causing generation of spatter and condensate, both of which have the potential to settle in the surrounding powder-bed compromising its reusability. In this study, 304L stainless steel powder is subjected to five reuses in the SLM process to assess its recyclability through characterization of both powder and mechanical properties. Powder was characterized morphologically by particle size distribution measurements, oxygen content with inert gas fusion analysis, and phase identification by X-ray …

Characterization Of Impact Toughness Of 304l Stainless Steel Fabricated Through Laser Powder Bed Fusion Process, Sreekar Karnati, Atoosa Khiabhani, Aaron Flood, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this research, the impact toughness of powder bed based additively manufactured 304L stainless steel was investigated. Charpy specimens were built in vertical, horizontal and inclined (45⁰) orientations to investigate the variation in toughness with build direction. These specimens were tested in as-built and machined conditions. A significant difference in toughness was observed with varying build directions. The lowest toughness values were recorded when the notch was oriented in line with the interlayer boundary. The highest toughness was recorded when the notch was perpendicular to the interlayer boundary. A significant scatter in toughness values was also observed. The variation and …