Engineering Commons^™

In-Situ Nanomechanical Testing Using X-Ray Microscopy, William Harris, Arno Merkle, Benjamin Hornberger, Hrishikesh Bale, Robert Bradley, Xuekun Lu, Philip Withers

Nanomechanical Testing in Materials Research and Development V

Micron-scale X-ray tomography, classically referred to as MicroCT, is a well-established 3D imaging technique and has seen various applications of in situ testing due to flexible sample types, sizes, nondestructive imaging, and lack of need for a vacuum enclosure. Recent advances in lab-based nanoscale X-ray microscopy (XRM) have moved beyond some of the physical constraints of traditional MicroCT by incorporating synchrotron-style optics and detection systems, extending spatial resolution down to 50 nm for samples tens to hundreds of microns in size. These nanoscale X-ray microscopes provide high resolution, nondestructive 3D imaging of interior structures on samples of tens to hundreds …

Size Dependent Deformation Of Beta Brass, Oscar Torrents, Bentejui Medina Clavijo, Carl Frick, Andreas Schneider, Eduard Arzt

Nanomechanical Testing in Materials Research and Development V

Previous research has shown that size scale dictates materials strength, reaching into the GPa range for specimens in the (sub-) micron regime. However, the influence of crystal structure on this ‘size-effect’ is poorly understood. In the present work, the deformation behavior of beta brass, which has a CsCl (B2) crystal structure and a low thermal component to the room temperature strength, has been studied through the compression of focused ion beam manufactured pillars at room temperature. The size dependence of beta brass is found to be close to that observed in FCC metals although the deformation processes differ significantly. While …

Testing Of Nanostructure Within Active Carbons Particles, Bronislaw Buczek

Nanomechanical Testing in Materials Research and Development V

Activation process with water-steam of carbonaceous precursors leading to the production of active carbons is noncatalytic reaction, which takes place in a gas-solid system.

Transport phenomena within porous particles depend strongly on the internal structure of the particles. Not too much experimental work has been done to understand how the tortuosity and hence effective diffusivity within the pore space are affected by the pore size distribution, pore shape, and nanostructure (micro- and mesopores).

The activating gas in the process is thought to penetrate the particle as a result of diffusion accompanied by chemical reactions, the gas concentration decreasing with distance …

A New Technique To Measure The True Contact Area Using Nanoindentation Testing, Gaylord Guillonneau, G. Kermouche, J.M. Bergheau, J.L. Loubet

Nanomechanical Testing in Materials Research and Development V

Nanoindentation technique requires the determination of projected contact area under load for calculation of modulus and hardness of materials. This projected contact area is usually calculated by models which take into account the pile-up or sink-in phenomena around the tip. The most commonly used model was developed by Oliver and Pharr [1] which can precisely model the sink-in around the tip, but cannot account for pile-up. Another model developed by Loubet et al can be used [2]. It can take into account the pile-up and the sink-in phenomena and can precisely measure the projected contact area for a large range …

Thermally Activated Deformation In Cast Aluminium Microwires, Suzanne Verheyden, Jerome Krebs, Andreas Mortensen

Nanomechanical Testing in Materials Research and Development V

We present a study on the thermally activated deformation behavior of aluminium (99.99%) microwires. The wires are prepared through a microcasting process based on a combination of lost pattern casting and pressure infiltration. In this manner microwires with a diameter between 7 and 100 µm can be cast. The wires are monocrystalline, have a surface roughness around 30 nm and are amenable for tensile testing. Their monotonic flow depends strongly on orientation, and displays a large number of stochastically distributed strain bursts. Relaxation tests are conducted on microwires with a diameter between 15 and 100 µm. The relaxations consist of …

Deformation Mechanisms Of Twinned Nanoparticles And Nanowires, Erik Bitzek, Wolfram Nohring, Andreas Kelling, Cynthia Volkert

Nanomechanical Testing in Materials Research and Development V

The plastic deformation of nanoscale metallic specimens has recently attracted a lot of interest due to the reported changes of deformation mechanisms with reduced size. Similarly, the interaction of dislocations with twin boundaries has received lots of attention in the context of the ultrahigh strength and ductility of nanotwinned metals. Here, we present experiments and atomistic simulations of compression test on twinned gold nanoparticles to study dislocation processes and -storage in nanosized volumes and dislocation-twin interaction mechanisms and compare them with the deformation behavior of twinned silver and gold nanowires.

Compression experiments were performed on triangular shaped, facetted particles using …

Length-Scale Enabled Quantification Of Surface Damage By Indentation: A Case Study Separating The Components Of Contact Response Due To Indentation Size, Residual Stress, And Damage Caused By Surface Machining And Grinding, Nigel Jennett, Xiadong Hou

Nanomechanical Testing in Materials Research and Development V

Instrumented indentation is a convenient and increasingly rapid method of high resolution mapping of surface properties. There is, however, significant untapped potential for the quantification of these properties, which is only possible by resolution of a number of serious issues that affect the absolute values for mechanical properties obtained from small indentations. The three most pressing currently are the quantification of the contributions to an indentation result due to: the Indentation Size Effect (ISE); Residual stress; and pile-up and sink-in – which is itself affected by residual stress and ISE.

We take as a case study the mapping of the …

Insights Into Dislocation Grain-Boundary Interaction By X-Ray Μlaue Diffraction, Christoph Kirchlechner, Nataliya Malyar, Peter Imrich, Gerhard Dehm

Nanomechanical Testing in Materials Research and Development V

The deformation behavior of metallic single crystals is size dependent, as shown by several studies during the last decade. Nevertheless, real structures exhibit different interfaces like grain, twin or phase boundaries. Due to the possibly higher stresses at the micron scale, the poor availability of dislocation sources and the importance of diffusion in small dimensions the mechanical behavior of samples containing interfaces can considerable differ from bulk material.

In the talk we show the first in situ µLaue compression experiments on micron sized, bi-crystalline samples. Three different grain-boundary types will be presented and discussed (i) Large Angle grain Boundaries (LAGBs) …

Measuring The Fracture Toughness Of Titanium Carbide Reinforcements At The Micronscale, Lionel Michelet, Martin Mueller, Vaclav Pejchal, Goran Zagar, Andreas Mortensen

Nanomechanical Testing in Materials Research and Development V

It is known that the mechanical properties of composite materials and alloys are strongly influenced by the intrinsic mechanical properties of their reinforcements or second phases. Such local properties are difficult to measure in particulate reinforcements or second phases because of the irregular shape and small size of material samples to be tested. We compare three methods that measure the fracture toughness of TiC reinforcements by combining focused ion beam (FIB) milling methods with nanoindentation techniques and finite element simulation. In-situ created TiC particles in a steel matrix are tested. Such particles are analysed by EBSD to select the crystalline …

Coalescence-Induced Jumping Of Nanoscale Droplets On Super-Hydrophobic Surfaces, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Coalescence-Induced Jumping of Tens of Microns Size Droplets on Super-Hydrophobic Surfaces Has Been Observed in Both Experiments and Simulations. However, Whether the Coalescence-Induced Jumping Would Occur for Smaller, Particularly Nanoscale Droplets, is an Open Question. using Molecular Dynamics Simulations, We Demonstrate that in Spite of the Large Internal Viscous Dissipation, Coalescence of Two Nanoscale Droplets on a Super-Hydrophobic Surface Can Result in a Jumping of the Coalesced Droplet from the Surface with a Speed of a Few M/s. Similar to the Coalescence-Induced Jumping of Microscale Droplets, We Observe that the Bridge between the Coalescing Nano-Droplets Expands and Impacts the …

A New Dynamic Module For In-Situ Nanomechanical Testing At High Strain Rate, Gaylord Guillonneau, J. Wehrs, G. Mohanty, D. Frey, S. Grop, J. Milchler, J.M. Breguet, Q. Longchamp, J.M. Wheeler

Nanomechanical Testing in Materials Research and Development V

In-situ nanomechanical testing is commonly used to probe surface mechanical properties of bulk materials or thin films, like hardness, Young’s modulus, Yield stress…Actually most of the instruments can measure these properties only statically, i.e. a low frequency, leading to property measurement only at low strain rate (usually 10^-1s^-1 by nanoindentation). This is mainly caused by the low resonance frequency of the system, preventing making tests at higher speed. Performing high dynamic measurements could bring new information on materials properties like deformation mechanism at high strain rate, or high dynamic fatigue properties.

A new high dynamic module usable …

Dislocation Dipoles And The Nucleation Of Cracks In Silicon Nanopillars, J. Rabier, F. Abed El Nabi, J. Godet, S. Brochard, L. Pizzagalli

Nanomechanical Testing in Materials Research and Development V

To understand the brittle to ductile transtion at small scale in silicon nanopillars, plastic deformation of silicon nanopillars was investigated by atomistic simulations. Perfect dislocations were found to be nucleated from surfaces and nano cavities were evidenced resulting from dislocation dipoles annihilation. The formation of such cavities is consistent with previous atomistic calculations showing that the annihilation of dislocation vacancy dipole of perfect shuffle dislocations is associated to the formation of vacancy clusters in silicon and diamond [1]. In nanopillars such cavities contribute to the nucleation of cracks [2]. This mechanism of crack nucleation is relevant to single slip deformation …

Development And Application Of An In-Situ Nanoindenter Coupled With Electrical Measurements, Solene Comby, Fabien Volpi, Florence Robaut, Rachel Martin, Francine Roussel, Frederic Roussel, Didier Pellerin, Marc Verdier

Nanomechanical Testing in Materials Research and Development V

The increasing demand for multifunctionality has become a recurring challenge for a wide panel of application fields such as microelectronics, microsystems, energy harvesting or structural applications.

This generally implies a smart combination of materials with tailored geometries, thus leading to ever more complex structures. The complexity of these new materials requires the development of higher performance characterization tools.

In that purpose, a multifunctional characterization set-up is developed in SIMaP laboratory, mainly based on electrical and mechanical coupling. This set-up is tailored for advanced measurements at the micrometer scale of structural and functional materials displaying small scale microstructure such as multiphase, …

A Direct Comparison Of High Temperature Nanoindentation And Tensile Creep Measurements For Aluminum, Warren Oliver, Richard Anthony, Sudharshan Pardhasaradhi

Nanomechanical Testing in Materials Research and Development V

Scanning electron microscope (SEM) in situ high temperature nanomechanical testing has received a lot of interest in recent times. Performing nanomechanical tests in non-ambient conditions presents several challenges. To meet those challenges a thorough understanding of the instruments’ performance both from static as well as dynamic point of view is required. In this regard, data from dynamic nanoindentation testing at temperatures up to 550 C on commercial purity aluminum in the SEM will be presented. The activation energy for creep was found to be 140 KJ/mol/K, matching the value determined with high temperature tensile creep experiments extremely well. The stress …

Micromechanical Behavior Of Thermal Barrier Coatings After Isothermal Oxidation, Carlos Serna, Deiby Maya, Alejandro Toro, Juan Meza

Nanomechanical Testing in Materials Research and Development V

Thermal protection of metallic components by using ceramic coatings like thermal barrier coatings (TBCs) is widely used, in rocket engines, aircraft industry and gas turbines for power generation to reduce the substrate temperature up to 165°C. This technology diminishes the heat transfer in combustor, initial rotor blades and nozzles guide vanes, so that turbines have taken special advantage of these coatings to meet increasing demands for greater fuel efficiency, lower NOx emissions and higher power and thrust [1]. Thermal barrier coatings, apart from thermal protection are also used to protect against abrasion, oxidation and corrosion [2].

The understanding of the …

Influence Of Temperature On The Deformation Behavior Of Single-And Bi-Crystal Microbending Beams, Jorge Velayarce, Mohammad Zamanzade, Oscar Torrents, Christian Motz

Nanomechanical Testing in Materials Research and Development V

The mechanical behavior of micron-scale structures varies drastically from their macro-scale counterparts. This phenomenon is known as size effect and has been extensively investigated for several decades. The understanding of the influence of temperature on the mechanical properties of components of electronic devices with micron or even sub-micrometer dimensions is essential for a reliable design. Hence micro-compression and micro-tension experiments on pure single-crystalline and polycrystalline face-centered cubic (fcc) metals have been carried out at different temperatures. However, in real microstructures complex stress and strain gradients arise from incompatibilities in elastic and plastic deformation, which are not addressed in tension or …

Chemomechanical Effects In Thin Film And Bulk Oxides, Steve Bull, Noushin Moharrani

Nanomechanical Testing in Materials Research and Development V

The environmental sensitivity of the surface mechanical properties of ceramics has long been known and properties such as plasticity, creep, fracture and fatigue have been shown to be susceptible to changes in the environment. These effects are often called Rehbinder effects after his pioneering work in the 1930s. Most relevant to indentation testing is “anomalous indentation creep” which has been observed by many workers in ceramics using both conventional microhardness and nanoindentation testing. Whereas a constant, time-independent hardness was found in microhardness measurements by testing in dry toluene the hardness was found to drop as the indentation time increased when …

Deformation Behavior Of Bulk Metallic Glasses Produced Via Severe Plastic Deformation And The Influence Of A Second Phase, Lisa Kraemer, Verena Maier, Karoline Kormout, Marlene Kapp, Yannick Champion, Reinhard Pippan

Nanomechanical Testing in Materials Research and Development V

Over the last years bulk metallic glasses (BMG) have been strongly investigated as their mechanical properties are very promising especially in terms of their high yield strength and high elastic strain. However, a major drawback is their complicated production depending strongly on dimensions and chemistry. A promising technique to overcome these drawbacks is using a severe plastic deformation process, e.g. high pressure torsion (HPT), where the production can be started with metallic glass powders, which are generally much easier to fabricate.

For this route, the powder is consolidated and then the powder particles are welded together by applying a high …

Mechanical Response Of Face-Centered Cubic Metallic Nanospheres Under Uniaxial Compression, Selim Haj Salah, Celine Gerard, Laurent Pizzagalli

Nanomechanical Testing in Materials Research and Development V

The mechanical response of metallic nanoparticles has recently attracted a lot of interest due to their specific properties compared to their bulk counterpart, which allow for novel applications in various fields, e.g., composite materials, nanomanufacturing/nano-electromechanical systems. We have employed Molecular Dynamic simulations to study the mechanical behavior of face-centered cubic metallic nanoparticles. Uniaxial compression of monocrystalline nanosphere is investigated using the EAM potentials developed by Mishin et al. [1] [2]. The resulting behaviors vary with nanoparticle size, crystallographic orientation, and temperature. This work shows that the elastic modulus of metallic nanoparticles is higher than that of the bulk material. Three …

Measuring Surface Dislocation Nucleation In Defect-Scarce Nanostructures, Daniel Gianola, Lisa Chen, Jungho Shin, Mo-Rigen He, Gunther Richter

Nanomechanical Testing in Materials Research and Development V

Linear defects in crystalline materials, known as dislocations, are central to the understanding of plastic deformation and mechanical strength, as well as control of performance in a variety of electronic and photonic materials. Despite a thorough understanding of dislocation structure and their interactions, measurements of the energetics and kinetics of dislocation nucleation have not been possible, as synthesizing and testing pristine crystals absent of defects has been prohibitively challenging. In this talk, experiments that directly measure the surface dislocation nucleation strengths in high qualityPd nanowhiskers subjected to uniaxial tension will be presented. We find that, whereas nucleation strengths are weakly …

Fracture Behavior Of High Strength Pearlitic Steel Wires, Bernhard Voelker, Anton Hohenwarter, Reinhard Pippan

Nanomechanical Testing in Materials Research and Development V

Steel wires are widely used in various industrial applications. Hence, the drawing process and the resulting mechanical properties are of significant scientific and industrial importance. In this investigation the focus is on pearlitic steel wires with relatively high drawing strains and resulting high ultimate tensile strengths up to several GPa.

The fracture behavior was investigated for two different wires with a drawing strain of 3.10 and 6.52 with a diameter of about 100 µm and 20 µm, respectively. The resulting ultimate tensile strength varies between 4 and 7 GPa [1]. The fracture toughness was measured with crack propagation direction in …

Quantification Of Mechanical Properties Gradient By Nano-Indentation And Microcompression Testing On Mechanically-Induced Transformed Surfaces, David Tumbajoy, Guillaume Kermouche, Sylvie Descartes, Jean Michel Bergheau, Gaylord Guillonneau, Johann Michler

Nanomechanical Testing in Materials Research and Development V

In the industry, there are several techniques which improve the service lifetime of materials by increasing the local mechanical properties in the near-surface. In the case of mechanical surface treatments (such as impact-based), the material is exposed to repeated mechanical loadings, producing a severe plastic deformation in the surface, and then leading to a local refinement of the microstructure into the affected zone (Tribologically Transformed Surfaces - TTS). The microstructure’s transformation is characterized by a progressive increment of the grain size from the surface until the bulk material. Consequently, very interesting physical properties such as high hardness and better tribological …

Ultra Small Scale High Cycle Fatigue Testing By Micro-Cantilevers, Jicheng Gong, Angus Wilkinson

Nanomechanical Testing in Materials Research and Development V

A new method has been developed for testing high cycle and very high cycle fatigue properties of materials at the micro-scale based on micro-cantilevers. Focused ion beam was employed to cut micro-cantilevers on the surface of a selected grain in a bulk polycrystalline commercial pure Titanium. The bulk specimen was pre-examined by EBSD, so the crystal orientation of all micro-cantilevers were known. The bulk sample with prepared micro-cantilevers was then attached to a high power ultrasonic generator, which can generate mechanical vibration at the frequency 20KHz. The bulk specimen moves with the ultrasonic generator, but the micro-cantilever lags somewhat behind. …

Comparison Of In Situ Micromechanical Time Dependent Plasticity Techniques: Micropillar Compression, Nanoindentation And Micro-Tensile Tests, Juri Wehrs, Gaurav Mohanty, Gaylord Guilloneau, Aidan Taylor, Brad Boyce, Jeffrey Wheeler

Nanomechanical Testing in Materials Research and Development V

Nanocrystalline metals exhibit strongly time-dependent plastic deformation. This results in a high degree of strain-rate sensitivity and susceptibility to creep and relaxation, even at room temperature. With the advent of thin film processing techniques like sputtering and electrodeposition for fabrication of controlled microstructures of nanocrystalline materials, nanoindentation and microcompression techniques are increasingly used to extract time dependent plasticity parameters from stress relaxation, creep and strain rate sensitivity measurements [1, 2]. However, no systematic comparison of the micromechanical experimental techniques (nanoindentation and microcompression) has been performed on the same material to establish the relative merits and consistency of …

The Measurement Of Viscosity Of Ultrathin Polymer Films, Dariusz Jarzabek, Wojciech Dera, Zygmunt Rymuza

Nanomechanical Testing in Materials Research and Development V

Viscosity is a very important property of thin polymer films used in modern microelectronic technology i.e. in nanoimprint lithography.Hence, in this work we present a method for viscosity of ultrathin polymer films determination. The viscosity is evaluated from the response of the oscillating piezoelectric cantilever at the end of which an indentation probe is mounted (Fig. 1a). When a polymer film is indented, the resonant frequency of the oscillations is changed and the parameters of used model (i.e. Maxwell model) can be identified. The frequency of the oscillations is equal to tens of kilohertz therefore the influence of extremely high …

Investigating The Plastic Deformation Of Molybdenum From -196°C To 950°C Using Nanoand Micro-Indentation, Katherine Plummer

Nanomechanical Testing in Materials Research and Development V

Understanding the plastic deformation at non-ambient conditions is critical to understanding materials’ behaviour in many applications including nuclear power. Molybdenum is seen as a potential candidate for nuclear fusion reactors due to its combination of high melting point and ease of processing. However it will be utilized under some of the most extreme engineering conditions anywhere – temperatures up to 1000K alongside high fluxes of both neutrons and alpha particles. For safe engineering design information on the behaviour of molybdenum under these conditions is needed.

In this work the temperature dependence of plasticity in single crystal Mo (bcc) has been …

Annealing Effect On Coherent-Incoherent Interface Tri-Component Nanoscale Metallic Multilayer Thin Films, Aidan Taylor, Rachel Schoeppner, Megan Cordill, Johann Michler, Hussein Zbib, David Bahr

Nanomechanical Testing in Materials Research and Development V

Multilayer coatings provide an excellent medium for the study of nanoscale materials’ properties. It has previously been shown that Cu/Ni/Nb tri-component multilayers with coherent and incoherent interfaces have a greater capacity for strain hardening than a Cu-Ni/Nb system, in which only incoherent interfaces are present [1]. This experimental evidence supports the predictions of the confined layer slip model in that the modulus-mismatched coherent interfaces in the tri-layer system increase the capacity of the multilayer to store dislocations, leading to greater hardenability.

In this work the same Cu/Ni/Nb tri-layers and Cu-Ni/Nb bilayers are investigated with regard to their thermal stability. In …

Ebsd Investigation Of Microstructure Refinement From Impact-Based Surface Treatments, Xavier Maeder, David Tumbajoy, Sylvie Descartes, Jean Bergheau, Cecile Langlade, Johann Michler, Guillaume Kermouche

Nanomechanical Testing in Materials Research and Development V

The mechanical surface treatments confer better local mechanical properties against wear or fatigue service conditions. In the case of impact-based treatments, a local microstructure’s refinement in the near surface is produced by a severe plastic deformation of the material, leading to a progressive reduction of the grain size over a few tens of microns, and consequently an increase of the hardness and tribological properties. These zones are commonly known as Tribologically Transformed Surfaces (TTS). In this project two different procedures are implemented to obtain TTS surfaces on pure iron samples: Shot-peening treatment and Micro-percussion tests. For the first technique the …

Nanomechanical Testing Of Ods Steels Irradiated With 1 Mev/Amu Heavy Ions, Kateryna Kornieieva, Vladimir Skuratov, Alexander Sohatsky, Jacques O'Connell, Yuri Golovin, Victor Korenkov, Jan Neethling

Nanomechanical Testing in Materials Research and Development V

Heavy ion beams with high damage production rate are widely used to evaluate radiation tolerance of promising nuclear reactor materials, such as oxide dispersion strengthened (ODS) alloys, including their mechanical properties. Since typical ion projected ranges do not exceed 1 micron, nanoindentation technique is the most convenient method for examination of irradiated materials.

In present work we report data on radiation hardening of several ODS steels irradiated with 107 MeV Kr and 167 MeV Xe ions. Some samples were irradiated trough the special Al-foil filter in order to obtain the unfolding damage profile on the surface. The post-irradiation testing steels …

Effects Of Lithiation On The Fracture Toughness And Mechanical Properties Of Limn2o4 Cathode Battery Materials, Marco Sebastiani, K.E. Johanns, Hugues Amanieu, G.M. Pharr

Nanomechanical Testing in Materials Research and Development V

The micro-pillar splitting method has been used to assess the influence of lithiation on the fracture toughness of Li_xMn₂O₄ micro-particles used as cathode materials in lithium ion battery composites. The materials under investigation consisted of hard LiMn2O4 particles embedded in a soft and compliant epoxy matrix to form the composite electrode. Five different samples were extracted from commercial battery cells at different states of charge (SoC% = 0-20-50-75-100%). These correspond to different lithium concentrations in the particles, as measured by inductively coupled plasma optical emission spectrometry (ICP-OES). Experimental results from the pillar splitting experiments show …