A5063843865- Shape Memory Alloy Transformations
- Ultrasonics and Acoustic Wave Propagation
- Acoustic Wave Resonator Technologies
- Titanium Alloys Microstructure and Properties
- Meat and Animal Product Quality
- Tree Root and Stability Studies
- Animal Nutrition and Physiology
- Seismic Waves and Analysis
- Magnetic Properties and Applications
- Ferroelectric and Piezoelectric Materials
- Intermetallics and Advanced Alloy Properties
- Optical measurement and interference techniques
- Thermography and Photoacoustic Techniques
- Non-Destructive Testing Techniques
- Hydrogen embrittlement and corrosion behaviors in metals
- Advanced Measurement and Detection Methods
- Thermal properties of materials
- Force Microscopy Techniques and Applications
- Bone Tissue Engineering Materials
- Nuclear Physics and Applications
- Engineering Technology and Methodologies
- Piezoelectric Actuators and Control
- High Entropy Alloys Studies
- Advanced MEMS and NEMS Technologies
- Metal and Thin Film Mechanics
Czech Academy of Sciences, Institute of Thermomechanics
2012-2025
Czech Academy of Sciences
2013-2014
Abstract In advanced applications such as aerospace and space exploration, materials must balance lightness, functionality extreme thermal fluctuation resistance 1,2 . Shape-memory alloys show promise with strength, toughness substantial strain recovery due to superelasticity, but maintaining low mass effective operation at cryogenic temperatures is challenging 3–6 We hereby introduce a new shape-memory alloy that adheres these stringent criteria. Predominantly composed of Ti Al chemical...
The effect of elastic anisotropy on thermal diffusivity determination by transient grating spectroscopy (TGS) was studied. In experiments performed a set cubic single crystals, it observed that TGS measurements may indicate in otherwise thermally isotropic materials, and the strength this apparent is correlated with anisotropy. To find source phenomenon, finite-element simulations were carried out. Time-domain signals generated from processed identically to experimental data. simulation...
The impulse stimulated thermal scattering experimental technique is used for contactless in situ detection of phase transitions thin nickel-titanium films deposited on silicon substrates. It shown that this enables the determination local properties film over a fully coated wafer, particular thickness and temperature dependence Young's modulus, can thus be monitoring spatial distribution functional prepared by combinatorial sputtering approach.
High mobility of twin boundaries in modulated martensites Ni-Mn-Ga-based ferromagnetic shape memory alloys holds a promise for unique magnetomechanical applications. This feature has not been fully understood so far, and particular it yet unveiled what makes the lattice mechanics Ni-Mn-Ga specifically different from other martensitic alloys. Here, results dedicated laser-ultrasonic measurements on hierarchically twinned five-layer (10 M) crystals fill this gap. Using combination transient...
<p>The study is focused on analysis of mechanical behavior hen’s eggshell expressed in terms average rupture force and corresponding deformation. Some other physical properties such as mass, length, diameter, geometric mean surface area, sphericity, volume were also evaluated. The egg samples compressed along their <em>X </em>and <em>Z</em>-axes. Two different experimental methods used: compression between two plates (loading rates 0.0167, 0.167, 1.67 mm/s)...
Paper deals with experimental research on the crushing of coffee beans different kinds under quasi-static and dynamic compression. The process is described in details. It has been shown that there variability strength values. A relation between grain shape also studied. Roasted Arabica (Coffea arabica) were used for analyses. coffees produced countries. All samples submitted to a light roast. detail analysis data shows no significant parameters describing fracture behaviour grains geometry....
Transient grating spectroscopy (TGS) with heterodyne detection is an opto-acoustic method for contactless measurement of surface acoustic wave velocities. The present objective to explore the possibility extracting bulk velocities from TGS spectra. has been carried out on CuAlNi shape memory alloy. By measuring in 180 directions a sample surface, angular map inverse (slownesses) constructed frequency A Ritz–Rayleigh approach was used calculate slowness surfaces verify results. correspondence...
Abstract High mobility of twin boundaries in modulated martensites Ni–Mn–Ga‐based ferromagnetic shape memory alloys holds a promise for unique magnetomechanical applications. This feature has not been fully understood so far, and particular, it yet unveiled what makes the lattice mechanics Ni–Mn–Ga specifically different from other martensitic alloys. Here, results dedicated laser‐ultrasonic measurements on hierarchically twinned five‐layer (10M) crystals fill this gap. Using combination...
An experimental system has been used to generate the impact force, measure response wave signal, and analyse frequency spectrum for physical property of Ostrich eggshell.The eff ects excitation point, detected point intensity on eggshell a light mechanical were analysed.The aim this study consists in evaluation main vibration properties which can be detection cracks eggshell.Four variables investigated determine if they are signifi cant classifying eggs by setting up relationship x-and...
Elastic constants of single crystals metastable β-phase the Ti-15Mo alloy were studied by ultrasonic methods with aim to observe dependence these on formation isothermal ω particles. Two applied: resonant ultrasound spectroscopy for monitoring temperature evolution elastic constants, and transient grating identification local material symmetry at a fixed temperature. Samples different heat treatments (isothermal ageing 300 °C under same uniaxial [111] loading) studied. The results prove that...
We report the results of an impulsive stimulated scattering measurement conducted on a 550 nm film Ni 2 MnGa MgO substrate, aiming at direct experimental observation highly temperature dependent elasticity.The phase velocity surface acoustic waves excited coating-substrate shows anomaly around transition MnGa, showing that it is possible to use as characterization tool determine elasticity thin film.
In advanced functional materials, where the prestress can initialize phase transitions or other structural changes, effect of increasing load on an acoustic wave velocity is substantial and provide important information undergoing physical phenomena.In this paper, a novel method for contactless measurements acousto-elastic parameters presented.The arrangement, based concept laser-ultrasound, enables accurate detection small changes velocities surface waves in various directions.Because...
In the presented paper, a sample of polycrystalline shape-memory NiTi alloy is studied under compression up to 5% by means laser-excited and laser-detected ultrasound waves.The evolution propagation velocity surface acoustic wave measured in situ during mechanical loading.An inverse method based on Ritz-Rayleigh numerical approach then used obtain development elastic properties sample.This process enables an analysis stress-induced transformation from austenitic martensitic phase with...
Despite the fundamental and technological importance of elastic constants, a suitable method for their full characterization in epitaxial films is missing. Here we show that transient grating spectroscopy (TGS) with highly k-vector-selective generation detection acoustic waves capable determination all independent coefficients an thin film grown on single-crystalline substrate. This experimental setup enables various types guided evaluation directional dependence speeds propagation. For...
Elastic constants of dual-phase β-titanium alloys with different phase compositions and volume fractions individual phases were investigated using resonant ultrasound spectroscopy transient grating spectroscopy. It was shown that even for high the secondary (ω α), crystals can retain cubic symmetry homogeneity in their elastic behavior, both at macro-scale micro-scale, unless precipitate under external stress violating this symmetry. In contrast, a material heat-treated uniaxial compression...
Determination of the elastic constants by RUS is an inverse problem because experimentally obtained resonant frequencies cannot be directly recalculated into constants. Instead, approximate spectrum calculated from dimensions and crystallographic orientation sample, its mass, a set 'guessed' constants, difference between this experiment iteratively minimized. has been used for determination either or orientations material in past, but recent advancements methodology, particular, employment...