Mechanical Characterisation at Nanometric Scale of a New Design of SOFCs (original) (raw)
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Relevance of Nanoindentation Experiments in Materials Research-A Review
International Journal of Advanced Materials Manufacturing and Characterization, 2013
Nano indentation is now commonly used for the study of mechanical properties of materials on the nanoscale.. It offers a direct measure of contact stiffness during the loading portion of an indentation test and, being somewhat insensitive to thermal drift, allows an accurate observation of small volume deformation. Nano scale damage caused by fatigue is of critical importance to the reliability of ultrathin protective overcoats and micro/nanostructures. The cyclic loading used in the nanoidentation makes the technique useful for the evaluation of nanofatigue. Methodologies of the nanoindentation technique used for the characterization of layered materials and nonhomogeneous composites are reviewed and discussed. Applications of the nanoindentation experiments to the measurement of contact stiffness, elastic modulus, hardness, creep resistance, and fatigue properties of the materials are presented. The nanoindentation in conjunction with nanoscratch and friction and wear tests, can be satisfactorily used for the materials characterization of magnetic storage and micro electromechanical systems (MEMS) devices and should find more application
Journal of Materials Research, 2012
ABSTRACT A new technique based on the detection of the amplitude of the second harmonic was described in a previous paper. To compute the elastic modulus and the hardness of materials, the technique uses only the derivative of the contact radius with respect to the indentation depth. For this reason, this method is applicable only to homogeneous materials. In this paper, the method is extended to any materials with constant Young modulus. The indentation depth value is not needed at all, thus eliminating uncertainties related to the displacement measurement, which are very influent at small penetration depths. Furthermore, we also explain how to compute the indentation depth from the detection of the amplitude of the second harmonic. This new measurement technique was tested on three samples: fused silica, Poly(methyl methacrylate) (PMMA), and calcite, which is expected to exhibit indentation size effect. The obtained results show that mechanical properties and the indentation depth can be determined with good accuracy for penetration depths between 25 and 100 nm using this method.
Materials & Design, 2020
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Using nano-indentation and microscopy to obtain mechanical properties
2015
Simulation of mechanical behaviour of heterogeneous materials is only possible if the local properties of the components are known. In recent years nano-indentation is being applied on different levels to obtain local mechanical properties. The aim of this paper is to explore various ways to obtain these properties by combining nano-indentation and microscopy. The method to prepare specimens and perform the testing is explained and the way the properties are used in the modelling is discussed.
Inter Laboratory Comparison and Analysis on Mechanical Properties by Nanoindentation
MRS Proceedings, 2009
This contribution presents the results obtained by a Mexican laboratory in the Asia-Pacific Economy Cooperation Interlaboratory Comparison (IC) on mechanical properties by nanoindentation from 2008 using fused silica and polycarbonate as samples. Reduced modulus and indentation hardness are the parameters asked to be measured and compared. The aim for this paper is to show and to discuss the so called "indentation size effect" (ISE) on the indentation hardness of fused silica. Using the spherical formulation of the ISE model for crystalline materials, the macroscopic hardness and material length scale of fused silica are determined as (7.34 ± 0.085) GPa and (166.36 ± 14) nm, respectively.
Novel nanoindentation method for characterising multiphase materials
Thin solid films, 1997
We present the nano-hardness tester (NHT), a new depth-sensing instrument with a differential capacitive sensor providing nanometer depth resolution and allowing partial elimination of the frame compliance. With micron lateral positioning of the sample and ...
Cross-sectional nanoindentation: a new technique for thin film interfacial adhesion characterization
Acta Materialia, 1999
AbstractÐInterfacial adhesion is becoming a critical material property for improving the reliability of multilayer thin ®lm structures used in microelectronics. Cross-sectional nanoindentation (CSN) is a new mechanical test especially designed for measuring the fracture toughness of thin ®lm interfaces. Interfacial fracture is achieved by nanoindentation in the structure cross-section. A model based on the elastic plate theory has been developed to calculate numerically the interfacial critical energy release rate (G ci ) for cer-amic±ceramic systems from CSN test results. The model inputs are the thin ®lm elastic properties, thin ®lm thickness, interfacial crack area and maximum thin ®lm de¯ection during the test. Closed form analytical solutions, obtained for two limiting cases, are consistent with the numerical approach. This technique has been successfully applied to silicon nitride±silicon oxide thin ®lms, commonly used as electrical isolators in microelectronic devices. # 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.
Acta Materialia, 2003
In this paper, it is shown that combining AFM, chemical etching and controlled polishing, progressively removing thin layers of material, allows a three-dimensional reconstruction of the volume distribution of dislocations about and under nanoindentation imprints. To illustrate the method, results obtained in MgO, a material known for its simple plasticity, have been selected. It is shown, comparing surface deformation and etching pattern, that the entire dislocation distribution associated with small indents can be analysed in terms of individual dislocations, leading to a better understanding of the elementary mechanisms of plasticity associated with the early stages of indents formation in crystalline material.
Approach to determine stress strain curves by FEM supported nanoindentation
Materialwissenschaft Und Werkstofftechnik, 2013
Nanoindentation is an often used method to characterize the hardness and the elastic modulus of thin coatings. Finding a method to determine the flow curve of thin coatings using analytical or numerical methods is one goal of actual nanoindenter research. In this work an approach is presented to determine the flow curve of materials using nanoindentation and finite element simulation (FEM). This method uses a FEM model of the indentation process. The determination of the flow curve is achieved by iteratively comparing experimental and simulated load-displacement curves and adapting the modelled plastic behaviour until both curves match. Analytical methods are used to determine boundary conditions for the flow curve and therefore reduce the number of possible solutions. The method is validated on material samples with known flow curves. The forecasted flow curves uniformly show good agreement with experimental measured flow curves. A critical discussion of the results and the future prospects is made.