Materials Science and Engineering Commons^™

An Improved Method For Point Deflection Measurements On Rectangular Membranes, Benoit Merle, Kyle Nicholson, Erik Herbert, Mathias Goken

Nanomechanical Testing in Materials Research and Development V

The point deflection method has recently emerged as a possible alternative to current micromechanical techniques for measuring the mechanical properties of thin films. A point deflection experiment consists into deflecting a clamped membrane in its center with a nanoindenter tip. The widespread availability of the required equipment makes the method very promising for future applications. These outlooks were further enhanced by the recent extension of the evaluation theory to rectangular membranes, which – unlike circular ones – are easily fabricated by standard lithographic techniques.

In this work, the recent theoretical advances were critically reviewed and an improved experimental method based …

Orientation Dependence Of Dislocation Transmission Through Twin-Boundaries Studied By In Situ Μlaue Diffraction, Nataliya Malyar, Nagami Jaya, Gerhard Dehm, Christoph Kirchlechner, Jean Sebastuen Micha

Nanomechanical Testing in Materials Research and Development V

It is well known that the grain boundaries (GBs) act as a barrier for dislocation motion (Clark 1992), leading to the well-known strength increase with reduced grain size, as explained by the Hall-Petch relation. Unfortunately the strength increase often leads to a reduction of ductility, except one example: Nano-twinned microstructures. The twin-boundary (TB) dislocation interaction is still not thoroughly understood (Imrich 2014, Gumbsch 2006).

Recent developments in deforming micron sized samples on synchrotron beamlines allow to study the interplay of the single dislocation with a specific grain boundary. In present work we conduct in situ compression on micron-sized copper specimens …

Study Of Sub-Surface Ion-Implanted Hardened Layers With Depth-Sensing Indentation, Alexey Useinov, Boris Chalikh, Pavel Lyamkin, Stanislav Andrianov, Alexander Niktin, Konstantin Kraychuk

Nanomechanical Testing in Materials Research and Development V

Ion implantation is an effective technique for designing structural materials for different industry applications. It may be used to improve various properties of steels such as corrosion resistance, heat resistance, wear resistance, hardness, etc. Based on their origin injected ions may serve as a coating or they may form a new phases such as carbides or nitrides that drastically change the material properties. In this work ferritic martenstic steel was irradiated with Ti and N ions followed with the heat treatment process. It is expected that it would cause the formation of the titanium nitride or titanium carbide precipitates in …

Short Course: Fracture And Adhesion - An Introduction (With Comments On Size Effects), Etienee Barthel

Nanomechanical Testing in Materials Research and Development V

This presentation is meant as a short, handwaving introduction to fracture mechanics and adhesion, a closely related problem. The similarity between the two notions will be underlined throughout the talk.

Trying to avoid technical details, we will first focus on the more general picture, ie how energy flows from the stressed body to the crack tick as the crack propagates (and also how it may flow from the crack tip to the body if allowed to – in the rare cases where the crack closes). We will also examine how these considerations lead to the important notion of crack stability …

Combining In Situ Tensile Testing And Orientation Microscopy In The Sem: A Mems Based Setup For Studying Time Dependent Deformation Of Thin Films By Tkd And Stem, Jan Philipp Liebig, Benoit Merle, Mathias Goken

Nanomechanical Testing in Materials Research and Development V

Structures in integrated devices are constantly subjected to residual or thermal stresses during operation. Understanding the relaxation behavior of thin films is therefore critical for improving their reliability.

Recently it was shown that Transmission Kikuchi Diffraction (TKD) in the Scanning Electron Microscope (SEM) enables the determination of local crystal orientations with high spatial resolution using standard Electron Backscatter Diffraction (EBSD) instrumentation [1, 2]. Giving access to quantitative information on mechanisms like grain growth, grain rotation and strain gradient evolution, time resolved TKD stands out as a promising technique for the characterization of microstructural changes upon relaxation of thin films.

We …

Using In-Situ Microlaue Diffraction To Understand Plasticity In Mgo, Ayan Bhowmik, T. Ben Britton, Finn Giuliani

Nanomechanical Testing in Materials Research and Development V

The present study investigates the micromechanical modes of deformation in MgO prior to cracking at room temperature. A combination of time resolved white beam Laue diffraction technique and in-situ nano-indentation of large single crystal micropillars provides a unique method to study the operating mechanisms of deformation in this otherwise brittle oxide ceramic. Upon indenting an [100]-oriented MgO micropillar, rotation and streaking of Laue spots were observed. From the streaking of the Laue spots, differential slip on orthogonal {110} slip planes was inferred to take place in adjacent areas under the indent - this was consistent with the results from the …

A Comparison Of Nanotribology And Nanoindentation, Steffen Brinckmann, Caroline Fink, Gerhard Dehm

Nanomechanical Testing in Materials Research and Development V

Metal friction and wear is the collective contact and interaction of asperities of micrometer dimension. We use a nanoindenter with tangential force measurement to simulate the behavior in engineering contacts and to fundamentally understand friction and wear.

This presentation investigates the deformation due to a single stroke scratch of a diamond nanoindenter in austenite base. We find that the elastic and plastic equations for static indentation also apply for the dynamic scratching. Additionally, the friction coefficient is found to be normal force dependent and we observe three domains: microstructure dominated friction, plastic plowing dominated wear and wear particle dominated tribology. …

Obtaining Mechanical Properties Of Superelastic Materials From Microindentation Data, Dmitry Zhuk, Margarita Isaenkova, Olga Krymskaya, Yuriy Perlovich

Nanomechanical Testing in Materials Research and Development V

Indentation is one of the most widely used techniques for determination of mechanical properties of materials. Many various methods for extraction of mechanical properties had been introduced for elasto-plastic materials. Later, the use of microindentation were extended to composite, porous, anisotropic and multi-phase materials. Use of microindentation for determination of such materials properties is impeded due to its complex behavior and larger number of material properties’ constants.

This work is focused on indentation of superelastic materials with austenite - martensite phase transformation and extraction of material properties. Finite element (FE) modeling was used to model indentation of superelastic alloys with …

High Temperature Nanoindentation Testing Of Amorphous Silicon Carbonitride Thin Films, Radim Ctvrtlik, Marwan Al-Haik, Valeriy Kilikovsky

Nanomechanical Testing in Materials Research and Development V

The mechanical properties of amorphous silicon carbonitride (SiC_xN_y) films with various nitrogen content (y = 0-40 at.%) were investigated in-situ at elevated temperatures up to 650 °C in inert atmosphere. The hardness and elastic modulus were evaluated using depth sensing nanoindentation with cubic boron nitride Berkovich indenter. Both the sample and indenter were separately heated during the experiments to temperatures 300, 500 and 650 °C. Short duration high temperature creep (1200 s) of the films was also investigated. The results revealed that the room temperature hardness and elastic modulus decline with the increase of the nitrogen …

The Measurement Of The Adhesion Force Between Ceramic Particles And Metal Matrix In Ceramic Reinforced-Metal Matrix Composites, Dariusz Jarzabek, Marcin Chmielewski, Tomasz Wojciechowski

Nanomechanical Testing in Materials Research and Development V

This paper presents the method for measurement of the adhesion force and fracture strength of the interface between ceramic particles and metal matrix in ceramic reinforced-metal matrix composites. Three samples with the following Cu to Al₂O₃ ratio (in vol.%) were prepared: 98.0Cu/2.0Al₂O₃, 95.0Cu/5.0Al₂O₃ and 90Cu/10Al₂O₃. Furthermore, microwires which contain a few ceramic particles were produced by means of electro etching. The microwires with clearly exposed interface were tested with use of the microtensile tester (Fig. 1). The microtensile tester consists of two stages, to which two …

Dynamic Triaxial Compression Experiments On Borosilicate And Soda-Lime Glass, John T. Chojnacki

Open Access Theses

A series of compression experiments were performed on borosilicate and soda-lime glass using a triaxial compression Kolsky bar. The triaxial compression Kolsky bar differs from a traditional Kolsky bar by having two pressure chambers, one enclosing the specimen and the other enclosing the end of the transmission bar, so that a specimen may be pre-stressed axially and radially before a dynamic axial load is applied. The result is a modified Kolsky bar capable of measuring axial deformation and axial stresses of a specimen at various strain rates under a range of confinement pressures. Borosilicate glass was subjected to triaxial confinement …

Influence Of Carbon Nanofillers On The Curing Kinetics Of Epoxy-Amine Resin, Luigi Vertuccio, Salvatore Russo, Marialuigia Raimondo, Khalid Lafdi, Liberata Guadagno

Chemical and Materials Engineering Faculty Publications

The cure kinetics of an epoxy resin based on the tetrafunctional epoxy precursor N,N′-tetraglycidyl methylene dianiline-(TGMDA) hardened with 4,4-diaminodiphenyl sulfone is investigated. The influence of carbon nanofillers (carbon nanotubes, carbon nanofibers, and graphene based nanoparticles) on the cure kinetic is studied. Kinetic analysis is performed by dynamic and isothermal differential scanning calorimetry (DSC).

In dynamic experiments, the activation energy was computed using an advanced isoconversional method while under isothermal conditions, the Kamal’s model of diffusion control was applied to simulate the systems throughout the curing process. The isothermal analysis shows that the introduction of the diluent decreases, …

Achieving Wing-Like Structural Response With Piezocomposite Unimorph Thin Plates, Francis Hauris

Mechanical & Aerospace Engineering Theses & Dissertations

This research investigates the geometric parameters that structurally influence static and dynamic bending and twisting of a wing-like plate when actuated with a surface-bonded piezoelectric material. The plate is parameterized using a finite element model that is validated by comparison with known analytical solutions. The geometric parameters analyzed for static and dynamic analysis are: the aspect ratio, actuator position, actuator angle, thickness-ratio of the active piezocomposite to the inactive substrate, and portion of the fixed end of the cantilevered structure that is fixed in the chordwise direction. For harmonically actuated cases, the resonant flapping frequency is also examined. Performance metrics …

Improving Response Characteristics Of Split Ring Resonators Using Experimental Designs, Omer Faruk Keskin

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this thesis is to investigate the application of design of experiments approaches in the analysis of split ring resonators, and to compare two different approaches. The design parameters of the meta-material device are examined to study all the main effects, the two factor interactions, and the curvature effects. A full factorial design and a central composite design is utilized for the study. The results in improving split ring resonator design are discussed.

This study shows that the design of experiments approaches can effectively be utilized to examine the effects on the response values of a specific type …

Determination Of The Polymerisation Rate Of A Low-Toxicity Diacetone Acrylamide-Based Holographic Photopolymer Using Raman Spectroscopy, Dervil Cody, Emilia Mihaylova, Luke O'Neill, Izabela Naydenova

Articles

The polymerisation rate of a low-toxicity Diacetone Acrylamide (DA)-based photopolymer has been measured for the first time using Raman spectroscopy. A value for the polymerisation rate of 0.020 s⁻¹ has been obtained for the DA photopolymer by modelling the polymerisation reaction dynamics as a stretched exponential or Kohlrausch decay function. This is significantly lower than the polymerisation rate of 0.100 s⁻¹ measured for the well known Acrylamide (AA)-based photopolymer composition. The effect of the additive glycerol on the polymerisation rate of the DA-based photopolymer has also been investigated. The inclusion of glycerol is observed to increase the rate …

Ozone Reaction With Interior Building Materials: Influence Of Diurnal Ozone Variation, Temperature And Humidity, Donghyun Rim, Elliott T. Gall, Randy L. Maddalena, William W. Nazaroff

Mechanical and Materials Engineering Faculty Publications and Presentations

Elevated tropospheric ozone concentrations are associated with increased morbidity and mortality. Indoor ozone chemistry affects human exposure to ozone and reaction products that also may adversely affect health and comfort. Reactive uptake of ozone has been characterized for many building materials; however, scant information is available on how diurnal variation of ambient ozone influences ozone reaction with indoor surfaces. The primary objective of this study is to investigate ozone-surface reactions in response to a diurnally varying ozone exposure for three common building materials: ceiling tile, painted drywall, and carpet tile. A secondary objective is to examine the effects of air …

The Effect Of A Reversible Shear Transformation On Plastic Deformation Of An Amorphous Solid, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

Molecular dynamics simulations are performed to investigate the plastic response of a model glass to a local shear transformation in a quiescent system. The deformation of the material is induced by a spherical inclusion that is gradually strained into an ellipsoid of the same volume and then reverted back into the sphere. We show that the number of cage-breaking events increases with increasing strain amplitude of the shear transformation. The results of numerical simulations indicate that the density of cage jumps is larger in the cases of weak damping or slow shear transformation. Remarkably, we also found that, for a …

High Temperature Oxidation Kinetics Of Dysprosium Particles, Brian J. Jaques, Darryl P. Butt

Materials Science and Engineering Faculty Publications and Presentations

Rare earth elements have been recognized as critical materials for the advancement of many strategic and green technologies. Recently, the United States Department of Energy has invested many millions of dollars to enhance, protect, and forecast their production and management. The work presented here attempts to clarify the limited and contradictory literature on the oxidation behavior of the rare earth metal, dysprosium. Dysprosium particles were isothermally oxidized from 500 to 1000 °C in N₂–(2%, 20%, and 50%) O₂ and Ar–20% O₂ using simultaneous thermal analysis techniques. Two distinct oxidation regions were identified at each isothermal temperature …

High-Frequency Electromagnetic Purification Of Silicon, Lucas Nana Wiredu Damoah, Lifeng Zhang

Materials Science and Engineering Faculty Research & Creative Works

The effect of a high-frequency electromagnetic (EM) field on the removal of nonmetallic inclusions from molten silicon was experimentally investigated. Inclusion separation efficiencies of up to 99 pct were reached. The separation efficiency was independent of the particle concentration in the melt and increased significantly with increases in the frequency, separation time, and coil current. Particles were separated from the silicon matrix and relocated to the top, bottom, and side walls of the crucible due to the effect of three mechanisms: induced secondary fluid flow which carried particles from the bulk of the melt; EM body force which worked in …

Structural And Functional Characterization Of A Lytic Polysaccharide Monooxygenase With Broad Substrate Specificity, Anna S. Borisova, Trine Isaksen, Maria Dimarogona, Abhishek A. Kognole, Geir Mathiesen, Anikó Várnai, Åsmund K. Røhr, Christina M. Payne, Morten Sørlie, Mats Sandgren, Vincent G. H. Eijsink

Chemical and Materials Engineering Faculty Publications

The recently discovered lytic polysaccharide monooxygenases (LPMOs) carry out oxidative cleavage of polysaccharides and are of major importance for efficient processing of biomass. NcLPMO9C from Neurospora crassa acts both on cellulose and on non-cellulose β-glucans, including cellodextrins and xyloglucan. The crystal structure of the catalytic domain of NcLPMO9C revealed an extended, highly polar substrate-binding surface well suited to interact with a variety of sugar substrates. The ability of NcLPMO9C to act on soluble substrates was exploited to study enzyme-substrate interactions. EPR studies demonstrated that the Cu²⁺ center environment is altered upon substrate binding, whereas isothermal titration …