Vibrating Reed Technique Research Articles

Temperature-Dependent Young’s Modulus of TaC- and TiC-Strengthened Co-Re-Based Alloys

The knowledge of Young’s modulus is important for a quantitative assessment of strengthening contributions in CoRe alloys, such as strengthening by carbides. In this work, the temperature-dependent Young‘s modulus of monocarbide-strengthened CoRe-based alloys is measured using the vibrating reed technique. In this method, a reed-shaped sample is excited electrostatically, and the eigenfrequencies are determined. Using these frequencies, Young’s modulus can be derived analytically or, more reliably, assisted by finite element simulations. The resulting values for Young’s modulus are compared to theoretical estimations, and the influence of titanium- and tantalum-carbides on Young’s modulus is evaluated. It was found that low amounts of carbides increase Young’s modulus significantly. Analytical estimations are in good agreement with experimental results of TaC-containing alloys, whereas estimations for TiC-containing alloys are inaccurate.

Effect of Annealing on Elastic Moduli of a FSMA

Ferromagnetic shape memory alloys (FSMA) are both ferromagnetic as well as have structural transformations from austenite to martensite and back. These structural transformations are generally studied through resistivity, magnetisation, etc. It is also known that annealing improves the physical properties of the FSMA systems. In this paper, we studied the effect of annealing on a typical CoNiAl FSMA system. However, in addition to the conventional methods, we also measured the elastic properties across the transition temperatures, and showed how the effect of annealing affects its elastic modulus. The measurements were done using a vibrating reed technique on thin samples that were annealed at two different temperatures. We also compared their properties in this paper.

Material and Mechanical Aspects of CMAS Damage Progression on Thermal Barrier Coatings and its Non-Destructive Detection

Thermal barrier coatings (TBCs) on turbine blades in gas turbine engines are in some cases damaged at high temperatures exceeding 1200°C by calcium-magnesium-alumino-silicates (CMAS) resulting from the ingestion of siliceous minerals. In this study, material interaction between molten CMAS and yttria-stabilized zirconia (YSZ) was investigated using a single crystal YSZ material and a synthetic CMAS product. Reaction between the molten CMAS and YSZ was significant at high temperature resulting in the infiltration of CMAS into the dense bulk-YSZ. The extent of interaction between CMAS and YSZ was found to be dependent on the crystallographic plane of the YSZ. The change in elastic stiffness due to the CMAS infiltration was also found by using a vibrating reed technique. The CMAS infiltrated layer had elastic stiffness higher by approximately five times of the non-infiltrated one. An attempt to detect the CMAS damage progression was also made through an AC impedance method. The proposed AC impedance technique is expected to be a useful technique to evaluate the CMAS infiltration as well as the associated delamination of TBC top coat.

1P2-33 Internal Friction Characterization of Positive Electrode of Lithium Ion Battery by Using Vibrating Reed Technique(Poster Session)

1P2-33 Internal Friction Characterization of Positive Electrode of Lithium Ion Battery by Using Vibrating Reed Technique(Poster Session)

Mechanical Spectroscopy of Annealing Effects in Electrodeposited Nickel/Ceramic Nanocomposites

The annealing behaviour of temperature-dependent mechanical spectra (vibrating-reed technique) was studied on electrodeposited ultrafine-grained nickel as well as on Ni nanocomposites with small (7 nm) SiO2or larger (25 nm) Al2O3nanoparticles. From the response of the different phenomena involved – Young’s modulus, high-temperature damping background, dislocation-and hydrogen-induced low-temperature loss peaks, and magnetomechanical effects – information is obtained on processes such as recovery, grain growth, hydrogen trapping, and dislocation generation by thermal stresses, which are influenced by both kinds of nanoparticles in different ways.

G040022 Vibrating reed法を用いた水素の属内拡散過程の観察([G04002]機械材料・材料加工部門一般セッション(2))

Vibrating reed (VR) technique can measure the Young's modulus which is dependent on the resonant frequency by making a thin board vibrate like a reed. In the previous report, it was shown that VR technique was effective as the way of measuring the degree of the absorption to the metal of hydrogen. Hence, the differences in the resonance frequency were found in some temperature range as a result of measuring the resonance frequency of the metal which absorbed hydrogen in hydrogen atmosphere, and that of the metal which didn't. In this report, after hydrogen was charged into sample SUS304 with the atmospheric pressure or 100MPa, changes in the resonance frequency were investigated in the diffusion process and in the separation process of hydrogen.

Anelastic Phenomena and Cr<sub>2</sub>N Precipitation in a High Nitrogen Austenitic Steel

Internal friction (IF) and dynamic modulus measurements on a high nitrogen (0.8 wt%) austenitic steel in the temperature range from room temperature to 800 °C have been carried out by using a vibrating reed technique with electrostatic excitation and frequency modulation detection of flexural vibrations in the frequency range of kHz. The IF spectrum of the as-prepared material shows a broad peak superimposed to an exponentially increasing background. The discontinuous precipitation of Cr2N phase changes the characteristics of the peak. The results have been discussed by considering interstitial-substitutional (i-s) interactions.

Adhesion coefficient and elastic properties of composite coatings on metallic substrate

In the present paper the elastic properties (apparent Young's modulus) of a composite coating (amine-epoxy resin + iron powder up to 40 vol.%) were examined by applying a vibrating reed technique (clamped-free configuration, frequency c.a. 100 Hz). Using tensile lap-shear strength tests (Instron machine) it was shown that adhesion coefficient of the examined composite coatings does not depend on iron powder content. In contrast to this Young's modulus of these coatings increases drastically with increasing powder content from 1.3 GPa (for powder free coating) to about 8 GPa (for 40 vol.% of iron powder). Moreover, Young's modulus also depends on powder grain dimensions and increases with decreasing a grain size. Magnetization measurements carried out for the composite coatings show some influence of powder grains interactions on magnetization processes at relatively weak magnetic fields i.e. up to μ 0 H = 0.8 T ( μ 0 is the vacuum permeability).

High temperature damping behaviour of Ti6Al4V–SiC f composite

The Ti6Al4V–SiC f composite, reinforced by unidirectional SiC fibres (SCS-6), has been investigated by internal friction (IF) and dynamic modulus measurements in the temperature range 300–1173 K. Experiments have been carried out by using a vibrating reed technique with electrostatic excitation and frequency modulation detection of flexural vibrations in the frequency range from 600 to 1800 Hz. For comparison the monolithic Ti6Al4V alloy has been submitted to the same experiments. The IF spectrum of the composite exhibits a relaxation peak at about 870 K superimposed to an exponentially increasing background. The peak, not present in the spectrum of matrix alloy, has activation energy H = 186 kJ mol −1 and relaxation time τ 0 = 2.3 × 10 −15 s. The peak has been explained by an interstitial-substitutional pair reorientation mechanism in the α phase of Ti6Al4V matrix around the fibres.

Single crystal PWA 1483 superalloy: Dislocation rearrangement and damping phenomena

The structural stability of the single-crystal PWA 1483 superalloy has been investigated by internal friction (IF) and dynamic modulus measurements from room temperature to 1073 K. The examined samples were in the solubilized state. The vibrating reed technique with electrostatic excitation and frequency modulation detection of flexural vibrations has been employed. Frequency was ∼350 Hz. IF spectra recorded in successive test runs on the same samples show a Q −1 maximum (M1) above 623 K, whose intensity and position change from one run to another; in correspondence with M1 the modulus undergoes a slow decrease followed by a sudden increase. Sometimes another maximum (M2) has been observed at lower temperature (∼523 K). After each run the values of the modulus and of Q −1 change indicating that a progressive irreversible transformation occurs. Damping phenomena have been attributed to the rearrangement of dislocation structures in the disordered matrix. This rearrangement modifies the density and the average distance of pinning points. This explanation is supported by transmission electron microscopy (TEM) observations.

Study of PPV Polymer Layers on Si Substrates by Mechanical Spectroscopy

Thin layers of the OLED related polyphenylene-vinylene (PPV) deposited by a precursor on micro-fabricated Si cantilevers were studied by applying the vibrating-reed technique during repeated temperature cycling between 100 and 520 K. By means of the Langmuir-Blodgett method for film production, the dependence of damping and elastic modulus on well defined values of film thickness (16 to 69 nm) was determined. Simultaneous measurements of these quantities showed four damping peaks during heating around 130 K (called γ), 250 K (β), 350 K (β’), and 400 K (called C). Three of them (γ, β’, C) disappeared after heating to the highest temperature (520 K) indicating their presence in the precursor only. The activation parameters of the relaxation peaks (γ, β, β’) were estimated and assigned to specific atomic movements in the molecule. Peak C occurs during the conversion process of precursor to polymer. Earlier results are essentially substantiated, indicating only slight differences to those for layers produced previously by spin coating. The observed thickness dependence of damping for the γ and β peaks suggests a weaker contribution of molecules in the surface region than of those in the bulk, while the β’ peak is supposed to result from molecules in the interface region between layer and substrate.

Comparing Irreversible and Reversible Structural Relaxation in Bulk and Ribbon Metallic Glasses Zr<sub>52.5</sub>Ti<sub>5</sub>Cu<sub>17.9</sub>Ni<sub>14.6</sub>Al<sub>10</sub> and Pd40Cu30Ni10P20 by Mechanical Spectroscopy

By means of the vibrating reed technique, measurements of internal friction have been performed in the temperature range of 120 K < T < Tg (= glass temperature) on two amorphous alloys, each produced as ribbon and bulk material. The different contents of free volume result in an only slight shift of the onset of irreversible structural relaxation to lower temperatures (i.e., lower activation energies) for the ribbons, while considerably different amounts of structural relaxation occur. After correcting for the thermoelastic effect, the reversible structural relaxation, i.e., an approximately exponential increase of damping with rising temperature, is well described by KWW kinetics (β ≈ 0.3). For the Zr-based alloy only, a clear relaxation peak occurs in the range from 270 K to 320 K (for the first flexural vibration mode between 100 Hz and 400 Hz) induced by hydrogenation. In addition, the effect of plastic deformation on the damping behavior by cold rolling of the bulk materials has been examined.

Influence of Al concentration on the short-range and long-range diffusion of carbon in Fe–Al alloys

Internal friction measurements have been performed with Fe–Al alloys in the temperature range of 100–960 K by the vibrating-reed technique. The concentration of Al was varied between 0 (pure iron) and 50 at.% Al (FeAl) to analyze the effect of Al. Four damping peaks have been observed. From the Snoek-type peak, the parameters of the short-range diffusion of carbon in Fe–Al alloys have been determined, while the isothermal annealing at temperatures near the Snoek-type peak has yielded information about the long-range diffusion during precipitation of carbides.

Scaling analysis of vortex phase transition in HgBa 2Ca 2Cu 3O 8+ x superconductors

Using the vibrating-reed technique, the internal friction (IF) Q −1 as a function of temperature is measured for sing-phase HgBa 2Ca 2Cu 3O 8+ x superconductor at low applied magnetic field up to 0.5 T. An IF peak associated with flux motion can be found below T C . The IF peak becomes higher and shifts towards lower temperature with increasing magnetic field. By using scaling theory we have demonstrated that the internal friction around the transition temperature can be collapsed into a single curve, indicating that the IF peak is originated from a phase transition associated with a vortex glass transition.

Scaling analysis of phase transition in Hg-based superconductor

With the vibrating-reed technique, the internal friction (IF) Q −1 is measured for sing-phase (Hg 0.66Pb 0.34)Ba 2Ca 2Cu 3O 8+ x superconductor as a function of temperature at low applied magnetic field up to 0.5 T and as a function of frequency at normal state temperatures. An IF peak associated with flux motion can be found below T C. The IF peak becomes higher and shifts towards lower temperature with increasing magnetic field. In addition an IF peak is found near 200 K. By scaling analysis we have demonstrated that the internal friction around the peak temperature can be collapsed into a single curve, indicating that the IF peak below T C is originated from a phase transition associated with a vortex glass transition and a structural phase transition occurs at around 200 K in the superconductor.

CHARACTERIZATION OF Al-ALLOYS (50xx) BY USING POSITRON ANNIHILATION, X-RAY DIFFRACTION AND VIBRATING REED TECHNIQUES

A series of Al – Mg x alloys, with x = 0.82, 2.09, 2.28, 2.49 and 4.47 wt.%, respectively were characterized by using positron annihilation lifetime studies (PAL), X-ray diffraction (XRD), and sound velocity and internal friction using a vibrating reed technique (VRT). PAL lifetime values increase linearly as the composition is varied, but texturing or preferential orientation is maximum at an intermediate value of composition (x = 2.49%). The internal friction shows a minimum at the same composition, and the sound velocity changes show the maximum value here too. This means that at this composition the sample is the most ordered and defect free.

H-induced anelasticity as a probe: Application to nanoscale quasicrystals

Anelastic relaxation peaks produced by hydrogen in icosahedral quasicrystals (at c H = 0.001 to 0.2 H/M) have been studied with the vibrating-reed technique in several rapidly quenched Ti/Zr-based alloys. Although a full quantitative theory of the expected Snoek-type mechanism is still missing, the properties of the relaxation peaks are considered as a probe of local atomic order on a more empirical level. Examples are presented which show the distinction between different icosahedral structure types (like Bergman or Mackay clusters), and the development of quasicrystalline order from amorphous and nano-quasicrystalline structures.

Mechanical properties of chemical vapor deposition-grown multiwalled carbon nanotubes

The bending modulus (Young’s modulus) of several chemical vapor deposition-grown multiwalled nanotubes (MWNTs) have been measured using a vibrating reed technique. Three different precursors were used to produce MWNTs with differing densities of defects in the tube walls. Individual MWNTs were electrostatically driven in air over a dark-field light microscope and the bending modulus of the nanotubes was determined from the frequency of the first vibrational resonance. A correlation between the defect density and the bending modulus was found which implies that the bending modulus is relatively more sensitive to wall defects than the nanotube diameter.

Magnetic flux pinning and flux jumps in polycrystalline MgB 2

MgB 2 polycrystalline samples were fabricated under varying conditions of isostatic pressing in argon gas. The critical current densities ( J C) were determined through measurements of hysteresis loops, and the highest value of J C at 10 K was 1.9 × 10 4 A/cm 2 at 4.8 T. The depinning temperatures were measured at various magnetic fields using the vibrating reed technique. Flux jumps appeared below 7.4 K. The hysteresis loops were carefully examined to determine the temperature and magnetic field range where flux jumps appeared.

Piezoelectric properties of lead-free CaBi4Ti4O15 thin films

Ca Bi 4 Ti 4 O 15 (CBTi144) thin films are evaluated for use as lead-free thin-film piezoelectrics in microelectromechanical systems. CBTi144 thin films were prepared on Pt substrates by dip coating a precursor solution of metal alkoxides. We fabricated a piezoelectric bimorph actuator using those films and analyzed the displacement induced by the electric field. Young’s modulus was measured by the vibrating-reed technique and the piezoelectric constant d31 was derived by analysis of bending displacement and measurement of displacement-voltage curve. The measurements revealed that the CBTi144 films had a large piezoelectric constant d31 of 32pm∕V.