Materials Characterization Laboratory
Department: Department D 5  Ultrasonic Methods Head: Ing. Petr Sedlák, Ph.D. 

The Materials Characterization Laboratory deals with both experimental and theoretical research in the field of Mechanics of Materials:
All of the above listed phenomena exhibit strong thermomechanical coupling (i.e. coupling between mechanics and thermal effects) and their investigation requires advanced experimental techniques as well as multiscale mathematical models. Their use for evaluation of thermomechanical properties of the examined materials (i.e. their elastic constants) usually requires complex and illposed inverse problems to be solved and MonteCarlo simulations to be performed in order to obtain realistic estimation of experimental errors. 
Ing. Petr Sedlák, Ph.D.
doc. Ing. Hanuš Seiner, Ph.D.
Ing. Lucie Bodnárová, Ph.D.
RNDr. Miroslav Frost, Ph.D.
Mgr. Barbora Benešová, Ph.D.
Ing. Martin Koller
Ing. Jitka Nejezchlebová
Ing. Martina Thomasová
Noncontact resonant ultrasound spectroscopy (RUS)
By using lasers both for the generation and for the detection of elastic vibrations, the resonant spectra of the specimens of the examined materials are obtained in a fully noncontact regime, i.e. not biased by any clamping forces from the ultrasonic probes. Simultaneously, the detecting laser beam scans the surface of the specimen, and thus, not only the resonant frequencies but the shapes of the eigenmodes are obtained.
Responsible researcher: Lucie BODNÁROVÁBICANOVÁ
Instrumentation: PolyTec MicroSystem Analyzer
Related publications: [NOVA09], [MSEA09], [APA09]
Numerical solution of the inverse problem of RUS
The determination of elastic coefficients from the resonant spectra is done inversely, i.e. the coefficients are tuned such that the spectra evaluated for them fit the experimental data in some optimal way. On this purpose, a software toolbox running under Matlab is developed, which enables not only the inverse determination of the elastic coefficients, but provides reliable estimates of the accuracy, and can be used also for calculation of thermal dependencies of individual coefficients, attenuation coefficients or determination of the material symmetry class.
Responsible researcher: Petr SEDLÁK
Related publications: [AM09], [APA09], [NOVA09], [IEEE06]
Measurements of elastic coefficients of individual phases of shape memory alloys and their thermal dependencies close to the transition temperatures
Shear softening in single crystals of austenite and single variants of martensite of the shape memory alloys (SMAs) in the vicinity of the transition temperatures is investigated by various ultrasonic methods (pulseecho technique, RUS). For the ferromagnetic SMAs (e.g. NiMnGa), the effect of the external magnetic field and the related magnetoacoustic phenomena (especially the damping) are also analyzed.
Responsible researcher: Michal LANDA
Collaboration with: IoP ASCR, Helsinki University of Technology.
Related publications: [APA09], [MSEA09], [MSEA08], [MSEA07], [AM05], [JAC04], [MSF05], [ULT04b], [NOVA09], [IEEE06]
Measurements of inplane elastic coefficients of thin surface coatings and layers
The elastic coefficients of thin (<1µm) surface layers are determined from differences between resonant frequencies of the substrate with and without the layer. This method is used for evaluation of DLC and SMA coatings.
Responsible researcher: Petr SEDLÁK
Collaboration with: IoP ASCR, IFW Dresden.
Related publications: [WIT09]
Experimental determination of the symmetry class and elastic coefficients of ultrafinely grained materials
The resonant ultrasound spectroscopy in combination with pulseecho measurements is used to analyze anisotropic elasticity of ultrafinely grained polycrystalline metals produced by equal channel angular pressing (ECAP). The symmetry of the examined material is estimated by a numerical search for planes of mirror symmetry.
Responsible researcher: Hanuš SEINER
Collaboration with: Charles University in Prague
Instrumentation: Polytec MicroSystem Analyzer
Related publications: [AM09]
Ultrasonic evaluation of fibrous composites
By using a combination of various ultrasonic methods (immersion techniques, pointsource/point receiver measurements) anisotropic elastic coefficients of fibrous composites are determined, either from velocity of propagation of bulk elastic waves, or by an inversion of dispersion curves of Lamb waves in thin plates.
Responsible researcher: Michal LANDA
Collaboration with: VZLÚ Letňany
Related publications: [ULT06], [ULT04a]
Elasticity of martensitic microstructures
By using a simple homogenization procedure, the averaged elastic properties of various microstructures thermoelastic martensites (differing in twinning systems, volume fractions, order of the laminate etc.) of can be evaluated. This enables the elastic coefficients of individual components to be determined from measurements of elasticity of the variously microstructured crystals.
Responsible researcher: Hanuš SEINER
Related publications: [APA09], [IJMCE09]
Experimental observations of interfacial microstructures in single crystals of shape memory alloys
Martensitic microstructures forming between austenite and the mechanically stabilized martensite in the single crystals of SMAs is observed by optical microscopy (2D analysis) and whitelight interferometry (3D analysis). The results are compared to the predictions of the mathematical theory of martensitic microstructures. The experiments are done on CuAlNi single crystals.
Responsible researcher: Hanuš SEINER
Collaboration with: Mathemetical Institute of the Oxford University, IoP ASCR
Related publications: [PT08], [PEAS07], [TMS09]
Mathematical modeling of elastically stressed martensitic microstructures
Finite element methods are used to analyze the elastic strain fields in interfacial martensitic microstructures, whereto the mesoscopic geometry of the microstructure is taken directly form the optical observations. The results enable the stored elastic energy to be evaluated and, consequently, the thermodynamic stability of individual microstructures to be discussed.
Responsible researcher: Hanuš SEINER
Related publications: [IJMCE09], [ESO09a]
Constitutive modeling of the thermomechanical behavior or SMA wires
A novel phenonemological algorithm is developed for predicting the behavior of NiTi shape memory wire elements under mechanical and thermal loading. The incorporated constitutive relation takes into account the key shape memory effects, e.g. superelasticity, pseudoplasticity, oneway shape memory effect, return point memory. Results of the numerical implementation of the algorithm are verified by comparison with experimental data.
Responsible researcher: Miroslav FROST, Petr SEDLÁK
Collaboration with: VTT Helsinki, Helsinki University of Technology
Related publications: [JMEP09], [ESO09b], [EPJ08]
Ultrasonic evaluation of elastic coefficients of curvilinear anisotropy
By using a simplified ray method, a mathematical model of interaction of planar acoustic waves with a curvilinear (cylindrical, spherical) anisotropic specimen is constructed. This model is then used for inverse determination of the elastic coefficients. The method was successfully applied on tubes made of fibrous composites and on cortical bovine bones.
Responsible researcher: Hanuš SEINER
Collaboration with: Laboratory of Biomechanics at Faculty of Mechanical Engineering (CTU in Prague)
Related publications: [BAM05], [MCMBEC07]
Characterizing of phase transitions in SMAs via acoustic emission
Detecting the acoustic activity (emission of acoustic pulses) during transformation and reorientation processes in shape memory alloys, with the aim to identify the microstructural mechanisms and the temperature/loading ranges in which these mechanisms are activated.
Responsible researcher: Michal LANDA
Collaboration with: IoP ASCR
Related publications: [JDP03], [JAC04], [ULT04b]
RUS analysis of anisotropic elasticity of rareearth scandates
Determining the anisotropy of bending stiffness of DyScO3 single crystals used for epitaxial growth of thin functional films and studying the evolution of their elastic coefficients with temperature. The information obtained on thin substrates with various orientations is used for the construction of the full orthorhombic elastic tensor.
Responsible researcher: Michaela JANOVSKÁ
Collaboration with: IoP ASCR
Related publications: [JPCM12]
Determination of inplane elasticity of supported plasmasprayed coatings
RUS analysis of assprayed coatings with high internal friction and possible heterogeneities; as these materials themselves cannot be set directly in resonance due to strong damping, their mechanical properties are determined from how the presence of such coating influences the vibrations of the underlying substrate. This method is used for HVOF and WSP coatings.
Responsible researcher: Hanuš SEINER
Collaboration with: IPP ASCR
Related publications: in preparation
Ultrasonic analysis of advanced ceramics prepared by SPS
Determination of elastic constants of ceramic materials and their possible spatial gradients by means of various ultrasonic methods. For a functionally graded silicon nitride, the profile of shear modulus along the phase composition gradient was determined from the asymetrization of modal shapes of free elastic vibrations of a small sample of this material.
Responsible researcher: Petr SEDLÁK, Hanuš SEINER, Martin KOLLER
Collaboration with: CSICICV Madrid, IPP ASCR
Related publications: [JASA12]
Acoustic DSC
Detecting the transition temperatures and the temperatures corresponding to other thermally triggered/activated processes from the evolution of RUS resonant spectra with temperature (locations of the peaks and internal friction). Studied materials: thin functional layers (NiTi, NiMnGa, BaTiO3), single crystals (SMAs, rareearth scandates), finely grained polycrystalline materials (e.g. AZ31 processed by ECAP), ceramics, etc.
Responsible researcher: Hanuš SEINER, Michaela JANOVSKÁ
Collaboration with: IoP ASCR
Related publications: [JAP12]
Papers
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Journals with Impact Factor
[AM14]. Kabla, M., Seiner, H., Musilova, M., Landa, M., Shilo, D. The relationships between sputter deposition conditions, grain size, and phase transformation temperatures in NiTi thin films (2014) Acta Materialia, 70, pp. 7991.
[JMPS14]. Seiner, H., Straka, L., Heczko, O. A microstructural model of motion of macrotwin interfaces in NiMnGa 10 M martensite (2014) Journal of the Mechanics and Physics of Solids, 64 (1), pp. 198211.
[JPCM13]. Seiner, H., Sedlák, P., Bodnárová, L., Drahokoupil, J., Kopecký, V., Kopeček, J., Landa, M., Heczko, O. The effect of antiphase boundaries on the elastic properties of NiMnGa austenite and premartensite (2013) Journal of Physics Condensed Matter, 25 (42), art. no. 425402.
[AM13b]. Seiner, H., Kopeček, J., Sedlák, P., Bodnárová, L., Landa, M., Sedmák, P., Heczko, O. Microstructure, martensitic transformation and anomalies in c′softening in CoNiAl ferromagnetic shape memory alloys (2013) Acta Materialia, 61 (15), pp. 58695876.
[CST13]. Seiner, H., Sedlák, P., Koller, M., Landa, M., Ramírez, C., Osendi, M.I., Belmonte, M. Anisotropic elastic moduli and internal friction of graphene nanoplatelets/silicon nitride composites (2013) Composites Science and Technology, 75, pp. 9397.
[AM13a]. Heczko, O., Straka, L., Seiner, H. Different microstructures of mobile twin boundaries in 10 M modulated NiMnGa martensite (2013) Acta Materialia, 61 (2), pp. 622631.
[SCT13] Sedmák, P., Seiner, H., Sedlák, P., Landa, M., Mušálek, R., Matějíček, J. Application of resonant ultrasound spectroscopy to determine elastic constants of plasmasprayed coatings with high internal friction
(2013) Surface and Coatings Technology, 232, pp. 747757.
[EPJB13] Heczko, O., Seiner, H., Sedlák, P., Kopeček, J., Kopecký, V., Landa, M. Resonant ultrasound spectroscopy  A tool to probe magnetoelastic properties of ferromagnetic shape memory alloys (2013) European Physical Journal B, 86 (2), art. no. 62.
[IJP12] Sedlák, P., Frost, M., Benešová, B., Ben Zineb, T., Šittner, P. Thermomechanical model for NiTibased shape memory alloys including Rphase and material anisotropy under multiaxial loadings (2012) International Journal of Plasticity, 39, pp. 132151.
[JPCM12] Janovská, M.  Sedlák, P.  Seiner, H.  Landa, M.  Marton, P.  Ondrejkovič, P.  Hlinka, J.: Anisotropic elasticity of DyScO3 substrates. Journal of Physics: Condensed Matter, Vol.24 (2012). art.No. 385404.
[JASA12] Seiner, H.  Sedlák, P.  Bodnárová, L.  Kruisová, A.  Landa, M.  de Pablos, A.  Belmonte, M.: Sensitivity of the resonant ultrasound spectroscopy to weak gradients of elastic properties. Journal of the Acoustical Society of America Vol.131(2012) (5), pp. 3775–3785.
[SM12] Straka, L.  Soroka, A.  Seiner, H.  Hänninen, H.  Sozinov, A.: Temperature dependence of twinning stress of Type I and Type II twins in 10M modulated NiMnGa martensite. Scripta Materialia, Article in Press (2012).
[JAP12] Heczko, O.  Seiner, H.  Sedlák, P.  Kopeček, J.  Landa, M.: Anomalous lattice softening of Ni2MnGa austenite due to magnetoelastic coupling. Journal of Applied Physics Vol.111 (2012), 07A929.
[JALCOM12a] Seiner, H.  Heczko, O.  Sedlák, P.  Bodnárová, L.  Novotný, M.  Kopeček, J.  Landa, M.: Combined effect of structural softening and magnetoelastic coupling on elastic coefficients of NiMnGa austenite. Journal of Alloys and Compounds, Article in Press (2012).
[JALCOM12b] Ball, J.M.  Koumatos, K.  Seiner, H.: Nucleation of austenite in mechanically stabilized martensite by localized heating
Journal of Alloys and Compounds, Article in Press (2012)
[AM11] Straka, L.  Heczko, O.  Seiner, H.  Lanska, N.  Drahokoupil  J., Soroka  A., Fähler, S.  (…)  Sozinov, A: Highly mobile twinned interface in 10 M modulated NiMnGa martensite: Analysis beyond the tetragonal approximation of lattice. Acta Materialia Vol.59 (2011) (20) , pp. 74507463.
[IJSS11] Seiner, H.  Glatz, O.  Landa, M.: A finite element analysis of the morphology of the twinnedtodetwinned interface observed in microstructure of the CuAlNi shape memory alloy
International Journal of Solids and Structures Vol.48 (2011) (13) , pp. 20052014
[JASA10] Růžek, M.  Sedlák, P.  Seiner, H. Kruisová, A. Landa, M.: Linearized forward and inverse problems of the resonant ultrasound spectroscopy for the evaluation of thin surface layers.Journal of the Acoustical Society of America Vol.128 (2010), pp. 34263437.
[AM09] Seiner, H.  Bodnárová, L.  Sedlák, P.  Janeček, M.  Srba, O.  Král, R.  Landa. M.: Application of ultrasonic methods to determine elastic anisotropy of polycrystalline copper processed by equalchannel angular pressing. Acta Materialia, Vol.58(2010) (1), pp. 235247. (Soubor PDF).
[PT09] Seiner, H.  Landa. M.: Nonclassical austenitemartensite interfaces observed in single crystals of CuAlNi. Phase Transitions, Vol.82(2009), No.11, pp. 793807 (Soubor PDF)
[IJMCE09] Seiner, H.  Glatz, O.  Landa, M.: Interfacial Microstructires in Martensitic Transitions: From Optical Observations to Mathematical Modeling. International Journal for Multiscale Computational Engineering, Vol.7(2009), No.5, pp.445456 (Soubor PDF).
[JMEP09] Vokoun, D.  Majtas, D.  Frost, M.  Sedlák, P.  Šittner, P.: Shape memory hooks employed in fasteners. Journal of Materials Engineering and Performance Vol.18(2009), Nos.(56), pp. 706710 (Soubor PDF).
[MSEA09] Seiner, H.  Bicanová, L.  Sedlák, P.  Landa, M.  Heller, L.  Aaltio, I.: Magnetoelastic attenuation in austenitic phase of Ni–Mn–Ga alloy investigated by ultrasonic methods. Materials Science and Engineering A. Volume A521522(2009), pp.205208. (Soubor PDF)
[APA09] Landa, M.  Sedlák, P.  Seiner. H.  Heller, L.  Bicanova, L.  Šittner, P.  Novák, V.: Modal resonant ultrasound spectroscopy for ferroelastics. Applied Physics A. Vol 96(2009), No. 3, pp.557567. (Soubor PDF)
[MSEA08] Landa, M.  Sedlák, P.  Šittner, P.  Seiner, H.  Heller, L.: On the evaluation of temperature dependence of elastic constants of martensitic phases in shape memory alloys from resonant ultrasound spectroscopy studies. Material Science and Engineering A. Vol. 481482(2008), pp.567573. (Soubor PDF)
[PT08] Seiner, H.  Sedlák, P.  Landa, M.: Shape recovery mechanism observed in single crystals of CuAlNi shape memory alloy. Phase transitions. Vol. 81(2008), No. 6, pp. 537551. (Soubor PDF)
[MSEA07] Landa, M.  Sedlák, P.  Šittner, P.  Seiner, H.  Novák, V.: Temperature dependence of elastic properties of cubic and orthorhombic phases in CuAlNi shape memory alloy near their stability limits. Material Science and Engineering A. Vol. 462(2007), pp. 320324. (Soubor PDF)
[ULT06] Seiner, H.  Landa, M.: Differential Geometry of Ray Surfaces in Anisotropic Solids and Its Contribution to NDE: Modelling and Experiment. Ultrasonics. 2006, vol. 44, no. Suppl. 1, pp. e801e806. (Soubor PDF)
[AM05] Sedlák, P.  Seiner, H.  Landa, M.  Novák, V.  Šittner, P.  Manosa, L.: Elastic constants of bcc austenite and 2H orthorombic martensite in CuAlNi shape memory alloy. Acta Materialia, Vol.53 (2005), pp. 36433661. (Soubor PDF)
[ULT04a] Seiner, H.  Landa, M.: Sensitivity analysis of an inverse procedure for determination of elastic coefficients for strong anisotropy. Ultrasonics. Vol. 43(2004), pp. 253263. (Soubor PDF)
[ULT04b] Landa, M.  Novák, V.  Sedlák, P.  Šittner, P.: Ultrasonic characterization of CuAlNi single crystals lattice stability in the vicinity of the phase transition. Ultrasonics Vol.42(2004) Nos.19, pp. 519526 (Soubor PDF)
[JAC04] Černoch, T.  Landa, M.  Novák, V.  Sedlák, P.  Šittner, P.: Acoustic characterization of the elastic properties of austenite phase and martensitic transformations in CuAlNi shape memory alloy. Journal of Alloys and Compounds, Vol.378(2004) Nos.12, pp. 140144. (Soubor PDF)
[JDP03] Novák, V.  Landa, M.  Šittner, P.: Acoustic recognition of stress induced martensitic transformations in Cubased shape memory alloys. Journal De Physique. IV : JP 112 (2003) No. I, pp. 593596.
[JTST03] Landa, M.  Kroupa, F.  Neufuss, K.  Urbánek, P: Effect of uniaxial pressure on ultrasound velocities and elastic moduli in plasmasprayed ceramics. Journal of Thermal Spray Technology Vol. 12(2003), No.2. pp. 226233
[ULT02] Landa M.  Plešek, J.: Contrast enhancement of ultrasonic imaging of internal stresses in materials
Ultrasonics. Vol.40(2002) Nos.(18), pp. 531535. (Soubor PDF)
Other Journals
[JOPC10] Landa, M., Růžek, M., Sedlák, P., Seiner, H., Bodnárová, L., Zídek, J.: Novel approach to material evaluation of thin surface layers by resonant ultrasound spectroscopy. Journal of Physics: Conference Series Vol.214(2010), art. no. 012045. (Soubor PDF)
[EPJ08] Heller, L.  Kujawa, A.  Šittner, P.  Landa, M.  Sedlák, P. Pilch, J.: Quasistatic and dynamic functional properties of thin superelastic NiTi wires. The European Physical Journal  Special Topics, Volume 158(2008), No.1, pp.714. (Soubor PDF)
[PEAS07] Seiner, H.  Landa, M.  Sedlák, P.: Propagation of an AusteniteMartensite Interface in a Thermal Gradient Proceedings of the Estonian Academy of Sciences. Vol. 56,(2007), pp. 218225. (Soubor PDF)
[BAM05] Goldmann, T.  Seiner, H.  Landa, M.: Experimental determination of elastic coefficients of dry bovine bone, Bulletin of Applied Mechanics Vol. 4(2005), pp. 262–275.
[MSF05] Landa, M.  Novák, V.  Sedlák, P.  Mañosa, L  Šittner, P: Elastic properties of structural phases in shape memory alloys investigated by resonant ultrasound spectroscopy. Materials Science Forum 482(2005), pp. 351354
Articles in Conference Proceedings (peer reviewed) and Chapters in Books
[NOVA09] Landa, M.  Seiner, H.  Sedlák, P.  Bicanová, L.  Zídek, J.  Heller, L.: Resonant Ultrasound Spectroscopy Close to Its Applicability Limits. In: Horizons in World Physics, Volume 268. Editors: Michael Everett and Louis Pedroza, Nova Science Publishers, 2009. (Soubor PDF)
[TMS09] Ball, J.M.  Koumatos, K.  Seiner, H.: An analysis of nonclassical austenitemartensite interfaces in CuAlNi. Accepted to Proceedings of ICOMAT08, TMS 2009.(Soubor PDF)
[ESO09a] Glatz, O.  Seiner, H.  Landa, M.: FEM Modelling of Elastically Strained Interfacial Microstructures in CuAlNi Single Crystals. In: The 8th European Symposium on Martensitic Transformations, 2009, edited by P. Šittner, L. Heller and V. Paidar, published by EDP Sciences (www.esomat.org).
[ESO09b] Vokoun, D.  Majtas, D.  Frost, M.  Sedlák, P.  Šittner, P.: Fastening of shape memory hook arrays. In: The 8th European Symposium on Martensitic Transformations, 2009, edited by P. Šittner, L. Heller and V. Paidar, published by EDP Sciences (www.esomat.org).
[WIT09] Seiner, H.  Růžek, M.  Sedlák, P.  Bicanová, L.  Landa, M.: Resonant Ultrasound Spectroscopy for Investigation of Thin Surface Coatings. In: Computational Methods and Experiments in Materials Characterisation IV. Wessex Institute of Technology, WIT Press, 2009. (Soubor PDF)
[MCMBEC07] Goldmann, T.  Seiner, H.  Landa, M.: Application of Simplified Ray Method for the Determination of the Cortical Bone Elastic Coefficients by the Ultrasonic Wave Inversion. 11th Mediterranean Conference on Medical and Biomedical Engineering and Computing, Springer, 2007. (Soubor PDF)
[IEEE06] Seiner, H.  Sedlák, P.  Landa, M.: Improvement of the Inversion Procedure in Resonant Ultrasound Spectroscopy for Generally Oriented High Anisotropic Crystals. In: Proceedings of the 2006 IEEE International Ultrasonics Symposium [CDROM]. New Jersey: IEEE, 2006. (Soubor PDF)