Engineering Commons^™

Characterization And Modeling To Design And Develop Tailored-Property Filled Glass Composites, Kevin Ewsuk

Composites at Lake Louise (CALL 2015)

Particle-filled-glass composites (FGCs) are being developed as new materials with structure and properties engineered for materials joining (e.g., for solid oxide fuel cells). Relative to conventional sealing glasses used to make hermetic glass-to-metal (GtM) seals, FGCs with tailored properties offer significant potential as more crack resistant hermetic seals with better performance and reliability. Additionally, compared to process sensitive crystallizable glasses, FGCs offer broader processing latitude and robustness, and afford greater control of seal microstructure and properties. FGCs are being developed using a combination of fundamental materials science and materials engineering, employing: 1) experimentally-validated molecular modeling to better understand and control …

Composite Metallic Nanofoam Structures, David Bahr, Matthew Howard, Mohamad Zbib, Raheleh Rahimi, John Balk

Composites at Lake Louise (CALL 2015)

Metallic nanofoams made of metals such as nickel (Ni) or gold (Au) with ligament sizes on the order of 10’s to 100’s of nm’s exhibit several remarkable properties as a consequence of their low relative density and high specific surface area, such as outstanding strength to weight ratios, enhanced plasmonic behavior and size-effect-enhanced catalytic behavior. However, these metallic nanofoams suffer from macroscopically brittle behavior due to plastic deformation in individual ligaments. With little or no barriers for slip, work-hardening is not possible within ligaments and extremely localized plasticity, once initiated, leads to a few ligaments necking and what appears to …

Powerful Artificial Muscles For Morphing Composites And Other Applications, Ray Baughman

Composites at Lake Louise (CALL 2015)

Three successive generations of twist-spun artificial muscles are described and used to make morphing composites and textiles that are electrically, thermally, or chemically powered.¹ Our first generation of twist-spun muscles, which are electrochemically powered by volume changes induced by double-layer charge injection, provide torsional rotation speeds of 590 rpm, and torsional strokes of 250° per millimeter of actuator length, which is 1000 times that for earlier artificial muscles. Our second generation muscles, which require no electrolyte and are based on guest-infiltrated carbon nanotube yarns, can torsionally actuate at 11,500 rpm and deliver 85 times higher power density during contraction …

Deterministic Three-Dimensional Composite Structures For Energy Storage, Paul Brown

Composites at Lake Louise (CALL 2015)

Through mesoscale design of a 3D current collector, high power density and high energy density primary and secondary (rechargeable) large format and microbatteries (Figure 1) were fabricated. At the most fundamental level, mesostructuring enables optimization of the trade-off between energy and power density in energy storage systems due to unavoidable ohmic and other losses that occur during charge or discharge. Of course, it is at fast charge and discharge, where these effects are most important. By efficient design of the ion and electron transport pathways, we and others have shown it is possible to significantly improve the power-energy relationship. We …

Diffusion-Based Deformation In Elevated Temperature Micropillar Compression Of Mg-Nb Multilayers, Keith Thomas, Juri Wehrs, Siddharta Pathak, Johann Michler

Nanomechanical Testing in Materials Research and Development V

multilayer, elevated-temperature, micropillar compression

Indentation Behavior Of Superelastic Hard Carbon, Olga Chernogorova, Ekaterina Drozdova, Iraida Ushakova, Evgenii Ekimov, Vicente Benavides, Aleksander Soldatov

Nanomechanical Testing in Materials Research and Development V

Supererlastic hard carbon particles up to 1 mmin size were produced by fullerene collapse upon high-pressure high-temperature treatment with simultaneous sintering of metal-matrix composite materials (CM) reinforced by such particles. The hardness of carbon particles can be varied in a wide range by changing the parameters of their structure, which consists of curved graphene planes or their packets of different sizes. Such carbon phase was called “nanoclusterd graphene phase” (NGP) [1]. The properties of the carbon particles were controlled by changing treatment pressure (5 and 8 GPa) and temperature (1100-1800 K), composition of parent fullerites (C60 or C60/70), and pre-treatment …

A Critical Review Of High Entropy Alloys (Heas) And Related Concepts, D.B. Miracle, O.N. Senkov

Beyond Nickel-Based Superalloys II

The field of high entropy alloys (HEAs) is barely 10 years old. It has stimulated new ideas and has inspired the exploration of the vast composition space. Here we give a critical review of this body of work, with the intent of summarizing key findings, uncovering major trends and providing guidance for future efforts. Based on detailed analysis, the following major results emerge. An intense focus is apparent on alloys based on first row transition metal elements. These efforts have discovered an extended, single-phase solid solution phase field and are exploring the extent and properties of this phase field. As …

Towards Nanoindentation At Application-Relevant Temperatures – A Study On Cmsx-4 Alloy And Amdry-386 Bond Coat, James Gibson, Sebastian Schröders, Christoffer Zehnder, Sandra Korte-Kerzel

Beyond Nickel-Based Superalloys II

With nickel-based superalloys reaching their fundamental limit in high-temperature applications, new alloys are required with improved mechanical properties. Small-scale mechanical testing – particularly nanoindentation – is of great benefit to alloy development, allowing hardness and modulus to be measured on small volumes of newly-developed materials.

We show that it is now possible to carry out such tests in vacuum up to 1000˚C, paving the way for candidate alloys and coatings to be tested at operation-relevant conditions. In this work, a <001> oriented single-crystal CMSX4 sample and a 200 µm Amdry-386 bond coat were tested using a modified MicroMaterials NanoTest indenter. 1 …

Microstructural Analysis And High Temperature Creep Of Mo-9si-8b Alloys With Al And Ge Additions, Peter Kellner, Rainer Völkl, Uwe Glatzel

Beyond Nickel-Based Superalloys II

Refractory metals and their alloys show potential for high temperature applications, due to the increased melting point and creep resistance. Spark plasma sintering technology as well as argon arc melting is used to prepare quaternary and quinternary Mo-9Si-8B-xAl-yGe (x is 0 or 2; y is 0 or 2) samples. Compositions are stated in at.%. All the compositions consist of a Mo solid solution (α-Mo) and two intermetallic phases: Mo₃Si (A15) and Mo₅SiB₂ (T₂). On the one hand, no zirconium is added to the alloys to avoid evaporation of MoO₃ due to the …

Γ/Γ' Co-Base Superalloys – New High Temperature Materials Beyond Ni-Base Superalloys?, Steffen Neumeier, Christopher H. Zenk, Lisa P. Freund, Mathias Göken

Beyond Nickel-Based Superalloys II

In 2006 a new L1₂ phase, Co₃(Al,W), was discovered in the Co-Al-W system which has led to the development of novel Co-base superalloys with g/g¢ microstructures similar to those of the well-established Ni-base superalloys. First investigations on simple ternary alloys could show that these Co-Al-W based alloys exhibit higher solidus temperatures and show less segregations after casting compared to typical Ni-base superalloys. This leads to the question whether this g/g¢ Co-base superalloys can be regarded as new class of high temperature materials that can compete with or even supersede established Ni-base superalloys.

In the first part of …

Microstructural Stability Of Co-Re-Cr-Ta-C Alloy Strengthened By Tac Precipitates, Debashis Mukherji, Ralph Gilles, Lukas Karge, Pavel Strunz, Přemysl Beran, Joachim Rösler

Beyond Nickel-Based Superalloys II

It is becoming increasingly clear that new materials that can operate at substantially higher temperatures than Ni-base superalloys are needed for future gas turbines. High melting Co-Re-Cr based alloy strengthened by carbides, particularly the MC type carbide, shows promise [1]. A fine dispersion of globular TaC precipitate is exploited for this purpose. Additionally Cr, which is mainly added to improve oxidation resistance, also stabilizes lamellar M₂₃C₆ type Cr carbide. The microstructure of a Co-Re-Cr-Ta-C alloy with the two types of carbides is seen in Fig. 1.

Please click Additional Files below to see the full abstract.

Enhanced Oxidation Resistance Of Ti-Rich Mo-Si-B Alloys By Pack-Cementation Process, Camelia Gombola, Daniel Schliephake, Martin Heilmaier, John H. Perepezko

Beyond Nickel-Based Superalloys II

To increase efficiency by higher combustion temperatures of aircraft engines and energy generation, new high temperature materials are inevitable. Mo-Si-B alloys for example satisfy several requirements such as good oxidation and creep resistance. Recently, novel Ti-rich Mo-Si-B alloys have shown an increased creep resistance compared to Ti-free Mo-Si-B alloys by the formation of Ti-silicide precipitates during processing. However, due to the formation of a duplex SiO₂ – TiO₂ oxide layer, where fast inwards diffusion of oxygen takes place, the oxidation resistance is poor.

In this study we show that oxidation resistance of Mo-Si-B-Ti alloys can be enhanced drastically …

Mo-9si-8b Alloys With Additons Of Zr – Microstructure And Creep Properties, Uwe Glatzel, Christian Hochmuth, Rainer Völkl

Beyond Nickel-Based Superalloys II

Three phase Mo-9Si-8B (at.%) alloys are a prominent example for a potential new high temperature structural material. Due to their high melting point and excellent creep resistance. In this study the effect of Zr addition (0…4 at.%) on the microstructure and creep properties of Mo-9Si-8B (at.%) alloys is investigated. Two powder metallurgical processes, hot isostatic pressing (HIP) and spark plasma sintering (SPS), are used to prepare specimens. The resulting microstructures are examined using SEM and TEM analysis. SPS alloys exhibit smaller grain sizes and fewer oxides compared to the HIP alloys, because of the oxygen availability during HIP. The more …

Design Of Gamma-Prime-Strengthened Co-Based Superalloys: Where We Are And Where We Need To Go, Eric A. Lass

Beyond Nickel-Based Superalloys II

Since the first report of a stable two-phase g-g’ (FCC-L12) phase field in ternary Co-Al-W in 2006, there has been significant research effort in developing this new class of Co-based g’-strengthened superalloys for high temperature applications. Much of the focus has been on characterizing and improving high temperature properties such as the g’ solvus temperature, high temperature strength and creep resistance, corrosion and oxidation behavior. Much of this work has been conducted experimentally utilizing the wealth of knowledge of Ni-based superalloys gathered over the last several decades. Efforts into developing effective modeling tools, such as thermodynamic and diffusion databases, have …

Microstructure And Creep Resistance Of Ti-Rich Mo + Mo5si3 + Mo5sib2 Alloys, Daniel Schliephake, Martin Heilmaier

Beyond Nickel-Based Superalloys II

New materials are necessary to increase efficiency of power generation and aircraft engines by higher combustion temperatures. Recently, it was found that alloying with high amounts of Ti replaces Mo₃Si by Mo₅Si₃ and stabilizes the phase field Mo + Mo₅Si₃ + Mo₅SiB₂, which could be beneficial for higher oxidation resistance, since Mo₅Si₃ is more oxidation resistant than Mo₃Si. Additional, Ti-rich Mo-Si-B alloys show an increased creep resistance compared to Ti-free Mo-Si-B alloys and a significant reduction in the alloy density. However, using the …

Conference Program, Howard J. Stone

Beyond Nickel-Based Superalloys II

No abstract provided.

Improving The Oxidation Resistance Of Refractory Metals Via Aluminum Diffusion Coatings And Halogen Effect, A.S. Ulrich, M.C. Galetz

Beyond Nickel-Based Superalloys II

Recently, refractory metals and their alloys have received increasing attention for the purpose of substituting Ni-based single crystal superalloys. Compared to commonly used materials, refractory metals have significantly higher melting points while their mechanical properties seem adequate at high temperatures. The main challenge for their application is, that refractory metals show low oxidation resistances at elevated temperatures. Aluminum diffusion layers are promising coatings to suppress harmful oxidation by forming a protective oxide layer. This study deals with the application of such aluminum reservoir layers and with the investigation of their protective properties. Four different unalloyed refractory metals, molybdenum, tantalum, tungsten …

From Dilute Polyelectrolyte Solutions To Entangled Polyelectrolyte Networks: A Study Of Sodium Carboxymethyl Cellulose In Water By Light Scattering And Rheology, Juliette S. Behra, Timothy N. Hunter, Olivier J. Cayre, Johan Mattsson

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

Sodium carboxymethyl cellulose (Na CMC) is widely used in industry for its thickening and swelling properties. Applications are very broad and include pharmaceutical, food, home and personal care products as well as the paper industry, water treatment and mineral processing. Na CMC is a linear negatively charged water-soluble polymer derived from cellulose. Its behaviour in water is known to be very complex and a function of several parameters including the characteristics of the polymer itself [1] such as molecular weight and degree of substitution as well as the solution concentration and dissolution conditions [2] (e.g. addition order of the system …

Soft Matter Films Interfaced To Electronic Devices: Capacitance-Modulated Field Effect Transistors Integrating Protein Layers, Gerardo Palazzo, Luisa Torsi, Maria Magliulo, Antonia Mallardi

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

Soft matter systems interfaced to an electronic device are presently one of the most challenging research activity that has relevance not only for fundamental studies but also for the development of highly performing bio-sensors.

Layers of proteins anchored on solid surfaces have small capacitance that undergoes to only minute changes as the ligand–protein complex is formed.

For properly designed systems, the protein layer represents smallest capacitance in a series of capacitors and as such dominates the overall capacitance. When such a protein layer is integrated in a Field Effect Transistor (FET) transduction is remarkably sensitive as the transistor output current …

Relative Humidity As A New Parameter In Rheological Testing, Jörg Läuger, Gunther Arnold

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

Besides temperature and pressure the water content of a sample as well as the relative humidity of the ambient air are important parameter influencing the rheological behavior of many complex fluids such as for example gels, biomaterials, polymeric systems, food products, and adhesives.

The aim of this contribution is to introduce a newly designed environmental control chamber for the use with a rotational rheometer.

A combination of a modified convection oven and an external humidity generator enables to work under defined relative humidity (RH) and temperature (T) in the ranges of RH = 5 to 95 % and T = …

Passive Microrheology As A Useful Tool For Milk Gel Analyses, Roland Ramsch, Giovanni Brambilla, Mathias Fleury, Pascal Bru, Gérard Meunier

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

Passive microrheology based on Diffusing Wave Spectroscopy (DWS) [1,2] is presented as a straightforward tool for the analysis of milk gel preparation. Diffusing Wave Spectroscopy consists of analysing the interferential images of light, which is backscattered by the sample. This so called speckles images, which are detected by a CCD camera, change in time due to the Brownian motion of the particles that scatter the light. The variation of the images as a function of time can be directly correlated to the viscoelastic properties of the sample. As it is an optical method, it is perfectly adapted to study the …

Non-Uniform Flow Of Colloidal Glasses And Gels: The “Shear-Gradient Concentration Coupling Instability”, J.K.G. Dhont

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

There are several types of shear-induced instabilities in soft-matter systems, like vorticity- and gradient-banding, that are by now well-understood. There is, however, an instability that can be referred to as “the Shear-gradient Concentration Coupling instability” (the SCC-instability) that has been largely ignored due to the lack of understanding of its microscopic origin, since its phenomenological description a few decades ago. This instability is due to a postulated shear-gradient induced mass flux together with a strong coupling of the stress to concentration. The origin of the shear-induced mass flux resulting from direct interactions is so far not understood, and explicit expressions …

Conference Program, Samiul Amin, Saad Khan

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

No abstract provided.

Super-Soft And Super-Elastic Dry Gels, Michael Rubinstein, William F. M. Daniel, Mohammad V. Vatankhah, Joanna Burdyńska, Krzysztof Matyjaszewski, Jaroslaw Paturej, Sergey Panyukov, Andrey V. Dobrynin, Li-Heng Cai, Thomas E. Kodger, Rodrigo E. Guerra, Adrian F. Pegoraro, David A. Weitz, Sergei S. Sheiko

Colloidal, Macromolecular & Biological Gels: Formulation, Properties & Applications

Molecular combs and bottlebrushes are a new class of polymer architecture allowing for anomalously low density of entanglements in polymer melts. The conformations and rheological properties of melts of these branched macromolecule composed of a flexible backbone and side chains densely tethered to it are investigated theoretically, experimentally and by computer simulations.^1,2 We develop the rule for dialing in the desired value of the melt plateau modulus of these molecules as low as 1000 times below the conventional values for linear polymer melts and experimentally verify the validity of our theory. The theory also predicts that elastomers made from …

Direct Numerical Simulation Of Reactive Flow Through A Fixed Bed Of Catalyst Particles, Abdelkader Hammouti, Florian Euzenat, Daniel Rakotonirina, Anthony Wachs

Sixth International Conference on Porous Media and Its Applications in Science, Engineering and Industry

Many catalytic refining and petrochemical processes involve two-phase reactive systems in which the continuous phase is a fluid and the porous phase consists of rigid particles randomly stacked. Improving both the design and the operating conditions of these processes represents a major scientific and industrial challenge in a context of sustainable development. Thus, it is above all important to better understand all the intricate couplings at stake in these flows: hydrodynamic, chemical and thermal contributions. The objective of our work is to build up a multi-scale modelling approach of reactive particulate flows and at first to focus on the development …

An Innovative Culture Technique For Microalgae Using Hollow Fiber Membranes, Yoshihiko Sano, Takeshi Suzuki, Akira Nakayama

Sixth International Conference on Porous Media and Its Applications in Science, Engineering and Industry

A hollow fiber culture system has been proposed for supplying the carbon dioxide to the microalgae, to replace the conventional air bubbling system which has been adopted to supply carbon dioxide in most conventional microalgal culture. In order to examine the usefulness of hollow fiber membranes for the microalgal culture, the microalgal growth rate for Chlorella sp. and the effective mass transfer coefficient of carbon dioxide through the hollow fiber membranes have been measured using the proposed photobioreactor filled with hollow fibers. The microalgal growth rate using hollow fiber membranes was found to be three times greater than that observed …

Active Nanomaterials For Biomedical Applications, Gianni Ciofani

Nanotechnology in Medicine: From Molecules to Humans

No Abstract,Please Click The Presentation.

A Mini-Review On The Fractal-Monte Carlo Method And Its Applications In Porous Media, Boming Yu

Sixth International Conference on Porous Media and Its Applications in Science, Engineering and Industry

Porous media widely exist in nature such as soil, rocks, sandstones, oil/gas//water reservoirs, biological tissue and organics, etc., and in many sciences and engineering applications. Since microstructures of porous media are extremely complicated, this makes very difficult to predict the transport properties such as thermal conductivities and permeabilities of porous media by analytical solutions. Usually, numerical simulations such as control volume method, molecular dynamics and Lattice Boltzmann method etc. are often applied. However, results by numerical simulations are often correlated as empiric expressions, which usually contain one or more empiric constants.

Please download the full abstract below.

Modeling Flow, Heat And Mass Transfer In A Porous Biomass Plug - When Used In An Electrically Heated Tobacco System, Markus Nordlund, Arkadiusz K. Kuczaj

Sixth International Conference on Porous Media and Its Applications in Science, Engineering and Industry

Heating porous biomass samples is utilized in many industries for drying or extracting Volatile Organic Compounds (VOC) from the biomass. The heating may trigger physical and chemical processes within the material, such as release of VOC, thermal degradation and evaporation. Most of the processes triggered by the increased temperature are occurring simultaneously and are strongly interdependent. For most practical applications, it is important to have control of the complex processes occurring during heating to generate stable and controllable release of VOC. This is the case for products delivering the released VOC to consumers by inhalation, as is the case of …

Numerical Investigation Of The Phase Change In Transpiration Cooling With The Vof Method, Xiao-Long Ouyang, Pei-Xue Jiang

Sixth International Conference on Porous Media and Its Applications in Science, Engineering and Industry

Transpiration cooling with phase change is numerically investigated in the present work. As shown in Figure 1, a liquid coolant flow is injected into a porous medium from the bottom side. The porous medium receives heat from the hot gas on the top surface and heats the coolant. Thus, phase change can occur in this porous medium. The surface temperature, the heat flux received by the porous medium, the phase distribution and the flow and cooling characteristics are the most important unknowns on this topic.

Please download the full abstract below.