Longitudinal Ultrasound Velocity Research Articles

Determination of the anisotropy in mechanical properties of laser powder bed fusion Inconel 718 by ultrasonic testing

ABSTRACT This study aims to investigate the effects of build direction on the as-fabricated microstructure and mechanical properties of Inconel 718 specimens manufactured via the Laser Powder Bed Fusion (L-PBF) technique. The microstructures and mechanical properties of the specimens were characterized via SEM, EBSD,ultrasonic wave velocity measurements, hardness and tensile tests. For the as-fabricated condition, the highest tensile strength (1114 MPa) was obtained with the horizontally built specimens while the vertically built ones have the highest 40% elongation. The computational analysis produced results that closely aligned with the measured yield strength values of L-PBFed samples. Additionally, a strong correlation was observed between the hardness values and longitudinal ultrasound velocity of L-PBF Inconel 718 specimens. Consequently, the non-destructive ultrasonic evaluation provided valuable insights into the anisotropy of mechanical properties, complementing information obtained from conventional tensile tests.

Phonon spectra and phase transitions in van der Waals ferroics MM’P2X6

For CuInP2S6 ferrielectrics by Brillouin spectroscopy, the temperature dependence of the longitudinal hypersound velocity was investigated for the acoustic phonons propagated in plane of the crystal layers. Pronounced softening of acoustic phonon branch is observed in the paraelectric phase below T* ≈ 330 K at cooling to temperature Tc ≈ 312 K of the first order phase transition into ferrielectric phase. Below Tc the hypersound velocity growth in correlation with spontaneous polarization rise and its temperature anomaly is similar to earlier observed temperature behavior of longitudinal ultrasound velocity for acoustic wave propagated normally to the structural layers. Determined anomalous part of the CuInP2S6 crystal thermal conductivity in the vicinity of the ferrielectric transition also demonstrates lowering of the heat transferring phonons group velocity with cooling from T* to Tc. Observed acoustic softening obviously is induced by flexoelectric coupling of relaxational soft polar optical and acoustic branches that is related to an in ingomogeneously polarized state appearing between the paraelectric and ferrielectric phases.

Influence of the coordination number and volume of a primitive cell on the vibration frequency of an iron atom during a polymorphic transition

Based on the polymorphic transition of iron from αFe to γFe, theoretical calculations of the longitudinal ultrasound velocity, the relationship between the number and primitive cell with a change in the vibration frequency of the atom was found.

In-situ measurement of the β to α phase transformation kinetics in a Ti-5553 alloy using laser ultrasonics

Ti-5553 alloy (Ti-5Al-5Mo-5V-3Cr wt.%) is one of the newest high strength metastable β-titanium alloys to be used in large section components of aircraft structures. Like other Ti-alloys, Ti-5553 can be strengthened by precipitation of the α-phase during aging heat treatments. In the present study, we explored the potential of laser ultrasonics for metallurgy (LUMet) as an in-situ tool to measure the α precipitation kinetics during high temperature isothermal aging in a Ti-5553 alloy. The observed change in longitudinal ultrasound velocity was seen to be linearly correlated with the α-phase fraction measured via post-mortem electron microscopy. The results are promising for a wider use of LUMet to design optimized heat treatment schedules for commercial Tialloys. Laser ultrasonics offers the potential for real-time monitoring of microstructure evolution in industrial production lines.

Longitudinal Ultrasound Velocity and Attenuation in Isotopically Enriched Cadmium

Longitudinal Ultrasound Velocity and Attenuation in Isotopically Enriched Cadmium

High-field ultrasound measurements inUPt3and the single-energy-scale model of metamagnetism

We report longitudinal ultrasound velocity measurements for magnetic fields up to 33 T applied parallel to the a-axis of the heavy electron compound UPt$_{3}$. A characteristic dip in the sound velocity at the metamagnetic critical field, $H_{c}=20$ T, reported in earlier work is reproduced and shown to be independent of temperature at very low temperatures. We show that the single energy scale model (B.S. Shivaram et al., Phys. Rev. B89, 241107(R), 2014) captures the observed key features of the field dependence in the sound velocity shift, $\delta v_{s}$. The shift $\delta v_{s}$ at $H_{c}$ is found to be inversely dependent on temperature above 3\thinspace K and assumes a fixed value at low T. This saturation in $\delta v_{s}$ below 3 K is accounted for by level broadening of the Uranium spin states.

Consolidation of carbonate stones: Influence of treatment procedures on the strengthening action of consolidants

This article demonstrates the importance of treatment application procedures on the consolidation effectiveness obtained by comparison of the results obtained using three different consolidants on four carbonate stone types, and proposes a general methodology for assessing the potential effectiveness of consolidants in laboratory conditions. It stresses the relevance of taking into account the treatment methodology, given the influence application protocols can have on the overall behaviour of the consolidated material. Several mechanical properties were assessed to demonstrate this influence on the performance of the consolidant. The results demonstrate that the strengthening action achieved with a specific product can only be defined in a strict relation to the treatment protocol used to produce it. The results also contribute towards the definition of standard testing protocols on stone consolidation. The application of a consolidant by direct contact capillary absorption is a reliable procedure and the results are easier to interpret than others obtained by brushing or by full immersion, thus making this procedure a good candidate for an eventual standard laboratory assessment method of the consolidation action of any specific stone/consolidant combination. This study also showed that the best test method to assess the strengthening action of stone consolidants in soft stones is DRMS (Drilling Resistance Measuring System). Moreover, the collection of longitudinal ultrasound velocity profiles determined in stones specimens treated by contact capillary absorption was shown to be a useful non-destructive method to assess the depth of the strengthening action achieved.

Tricritical Behavior of Sn2P2S6 Ferroelectrics at Hydrostatic Pressure

For Sn2P2S6 ferroelectrics with three-well potential under hydrostatic compression the second order phase transition approaches tricritical point as expected according to Blume-Emery-Griffiths (BEG) model. Joint consideration of BEG model and known ANNNI model, describing the incommensurate phase appearing as a result of competitive interactions, allows one to draw conclusion about possibility of tricritical point presence on temperature-pressure diagram of Sn2P2S6 without incommensurate phase appearing. Investigations of temperature dependences of longitudinal ultrasound velocity at different pressures for Sn2P2S6 crystals confirm such conclusion.

Characterization of cortical bone fracture with scanning confocal ultrasound and longitudinal acoustic velocity.

Non-invasive assessment of fracture, particularly in non-typical fracture, is a critical health problem. As a promising alternative to the x-ray, ultrasound has demonstrated potentials in early fracture diagnosis. A real-time scanning confocal ultrasound image was developed to evaluate bone defect and bone loss. The objectives of this study were to evaluate the cortical fracture gap size using quantitative ultrasound imaging and the longitudinal ultrasound velocity in bone to predict the fracture gap size. The total fractures were created by MTE compression at the middle diaphysis, with gap size varied from 1–5 mm (N=4). Fractures were tested with the ultrasound scanning with 0.5-mm resolution. The measured ultrasound signals were analyzed to calculate BUA (dB/MHz), ATT (dB), and transverse velocity (m/s). The longitudinal wave velocity was tested using three surface transducers. Strong correlations were observed between ultrasound and x-ray images in fracture size (R2=0.91). High correlation was found between gap size and the longitudinal velocity from 4000 to 3000-m/s for 0–5-mm gaps (R2=0.93). These results suggest that ultrasound is capable to predict bone fracture and provide useful information for longitudinal assessment of complications, such as non-union fracture, and for evaluating healing. [Work supported by NSBRI/NASA and NIH.]

Influence of power density on the setting behaviour of light-cured glass-ionomer cements monitored by ultrasound measurements

Objectives To monitor the influence of the power density of the curing unit on the setting behaviour of light-cured glass-ionomer cements (LCGICs) using ultrasound measurements. Methods The ultrasound equipment comprised a pulser–receiver, transducers and an oscilloscope. The LCGICs used were Fuji II LC, Fuji II LC EM and Fuji Filling LC. The cements were mixed according to the manufacturer's instructions and then inserted into a transparent mould. The specimens were placed on the sample stage and cured with power densities of 0 (no irradiation), 200 or 600 mW/cm 2. The transit time through the cement disk was divided by the specimen thickness and then the longitudinal ultrasound velocity ( V) within the material was obtained. Analysis of variance and Tukey's Honestly Significantly Different test were used to compare the V values between the set cements. Results When the LCGICs were light-irradiated, each curve displayed an initial plateau at ∼1500 m/s and then rapidly increased to a second plateau at ∼2600 m/s. The rate of increase of V was retarded when the cements were light-irradiated with a power density of 200 mW/cm 2 than with a power density of 600 mW/cm 2. Although sonic echoes were detected from the beginning of the measurements, the rates of increase of the sonic velocity were relatively slow when the cement was not light-irradiated. Conclusions The ultrasound device monitored the setting processes of LCGICs accurately based on the longitudinal V. The polymerization behaviour of LCGICs was shown to be affected by the power density of the curing unit.

Possible Sound Mode Conversion in “Superfluid 4He-97% Open Aerogel” System

We have studied the acoustic properties of liquid helium filled in various aerogels. The longitudinal ultrasound velocity and attenuation were measured at the frequency of 10 MHz with aerogels that had porosity from 92 to 97%. The mode intermediate between first and fourth sound was observed. The attenuation of this mode decreased with decreasing temperature for dense aerogels. However, an attenuation maximum was observed around 1.6 K for 97% open aerogel at various liquid pressures. In the present work, we discuss the possibility of the sound modes conversion between first, second sound in superfluid and aerogel sound mode in this composite system.

The laterally varying ultrasonic velocity in the dentin of human teeth

There is no quantitative description available that numerically relates any acoustic parameter pattern or the local elastic behaviour to any standardized geometrical positions within human teeth. However, the speed of ultrasound at 20 MHz varies in different parts of teeth. Great differences occur between the values attributed to longitudinal waves that propagate in the three mineralized human hard tissues at identical relative tooth width portions [John, C., 2004. The corono-apically varying ultrasonic velocity in human hard dental tissues. Journal of the Acoustical Society of America 116, 545–556]. The aim of this work was to investigate the distribution of the longitudinal ultrasound velocity (LUV) at distinct relative tooth width portions and at a height level of 8 mm relative to the coronal reference. Individual tooth widths w were accounted for, and a standardized, dimensionless radial distances variable X = | x / w - 0.5 | was utilized to express the radial position of measurements in a unified way. The observed lateral increase in LUV of 21 specimens along X was approximated. A Padé shape function predicts the lower contour of the envelope curve of all the individual LUV distributions. Individual residuals and coefficients are provided for LUV = a + b · ln ( X ) · X · X , where a and b represent individual intercepts and slope factors (e.g. a = 3206 m / s and b = - 4184 m / s ), respectively.

Pressure dependence of the sound velocity of 4He in aerogel

Acoustic properties have been studied in 4He–aerogel system. The longitudinal ultrasound velocity and attenuation have been measured in 92.6 and 94.0% porous aerogels at elevating pressures from the saturated vapor pressure to the melting point for both normal and superfluid phase. The temperature dependence of the sound velocity was similar to that of bulk liquid. The superfluid transition temperature was determined by a dip in velocity and a sharp peak in attenuation. The sound velocity was analyzed using a hydrodynamic theory for both phases. The pressure and temperature dependencies of the sound velocity in the normal phase can be rather well explained by a simple hydodynamic theory. However, at the lowest temperature where no normal component is expected, the sound velocity behavior differs significantly from the case of bulk case. It is shown that coupling mechanism between acoustic phonons in the liquid and aerogel matrix other than viscosity is necessar to elucidate the sound velocity below 1 K.

The corono-apically varying ultrasonic velocity in human hard dental tissues.

The speed of ultrasound at 20 MHz is measured for hard dental tissues inside human teeth. This includes the cementum, for which no data are available. The spatial distribution, extrema, and means of the longitudinal ultrasound velocity (LUV) are determined with an emphasis on the apical thirds and an extended spectrum. Tissue areas are investigated by optical means and by acoustical scanning, in order to compare apical regions-of-interest with the complete mineralized wet porous tissue that lies beneath the enamel cap. The maximal LUV in a single dentin specimen varies from 3903 m/s to 4226 m/s. The dentin's frequency distribution of LUV at 20 degrees C exhibits a predominant peak feature comprising several Voigt functions. Introducing standardized relative tooth width portions, the corono-apical decrease in LUV of 21 specimens is approximated by LUV=4224 - (257* ln(y)) along reduced distances in dentin. Abnormal teeth require a higher resolution and an approximate equation of the form LUV= (sigma(ai*yi))/(1 + sigma(bi+1*y(i+1. It can be used each time the corono-apical variation has to be quantified in each of the three tissues. Ten coefficients are numerically exemplified. An error evaluation is performed, which denotes errors of 0.2% +/- 1.3% (enamel), -0.1% +/- 1.6% (cementum), and acceptable residual errors for dentin.

Investigation of elasto-mechanical properties of alginate microcapsules by scanning acoustic microscopy.

High-frequency scanning acoustic microscopy (SAM) was used for investigation of acoustic impedance and 3D-surface topography of full alginate microspheres that act as model of artificial biological cells. Elasto-mechanical properties of the investigated specimens have been characterized by acoustic impedance. Mean surface impedance of microspheres (diameter: 300 microm) was measured with SAM at 900 MHz with a spatial resolution of 1.5 microm. The sensitivity and reproducibility of SAM had to be increased considerable to receive and quantify signals in the very low impedance region. The multilayer analysis method was used to get quantitative data of acoustic impedance with SAM at a microscopic level. 3D images show details of structure and surface topography. As a reference, bulk measurements were performed on full alginate cylinders. The acoustical impedance and the mechanical stiffness c(11) were obtained from mass density and longitudinal ultrasound velocity at 6 MHz. The impedances received with both methods are in close agreement. The results demonstrate the SAM as a powerful tool for characterizing mechano-elastical parameters as well as surface structure and topography of microspheres with high spatial resolution.

Isothermal compressibility and elastic properties of TlInS 2 -TlDyS 2 alloys

The isothermal compressibility of TlIn1 – xDyxS2 (x= 0.01, 0.02, 0.05, 0.08) solid solutions is measured in the range 77–400 K and is found to increase with temperature. The compressibility data are used to evaluate the shear modulus, Young's modulus, Poisson's ratio, and longitudinal ultrasound velocity of the solid solutions. The elastic constants of TlIn1 – xDyxS2 are shown to increase with Dy content, which is attributable to a weakening of chemical bonding.

Ultrasonic Studies of (CH3)2NH2Al(SO4)2 · 6H2O crystals irradiated by γ quanta and electrons

The temperature dependence of the longitudinal-ultrasound velocities in (CH3)2NH2Al(SO4)2 · 6H2O crystals was studied using the echo-pulse technique in the 90–300 K range. The measurements were carried out along mutually perpendicular crystallographic directions X, Y, Z on samples both unirradiated and irradiated to various doses by γ quanta and an electron beam. The ultrasound velocity V in this crystal was shown to be anisotropic, with V YY >V XX >V ZZ . The V XX =f(T), V YY =f(T), and V ZZ =f(T) curves exhibit anomalies in the form of breaks at the ferroelectric phase transition (PT) at T c1=152 K, as well as in the region of T c2=218 K. It was established that as the irradiation dose increases, the PT temperature T c1 decreases and the anomalies in the temperature dependences of the ultrasound velocities are smeared.

Ultrasonic studies of para-ferroelectric phase transition in DMAGaS crystal

Longitudinal ultrasound velocity was measured for DMAGaS crystal along the x, y and z direction, where x is parallel to spontaneous polarization direction and y is parallel to the two-fold crystallographic axis. Anomalous changes of ultrasound velocity give evidence for the first-order phase transition at Tc1 = 135 K, close to the tricritical point.

Ultrasonic behavior in La 2−xBa xCuO 4−y polycrystalline superconductor

Measurements of longitudinal ultrasound velocity and attenuation in polycrystalline single-phase La 2−xBa xCuO 4−y (0 ≤ x ≤ 0.18) were performed. A clear discontinuity of sound velocity was observed near 60K for all samples. This discontinuity was also accompanied by a peak in the attenuation.

Tibial ultrasound velocity measured in situ predicts the material properties of tibial cortical bone

Quantitative ultrasound (QUS) is currently being investigated as a possible alternative or adjunct to X-ray-based methods for assessing osteoporosis and fracture risk. It has been proposed that QUS may allow measurement of bone “quality,” such as bone architecture or material properties. In this study, we used human cadaveric specimens to evaluate whether ultrasound velocity measurements performed in situ at the midtibia were correlated with the mechanical properties of tibial cortical bone. We obtained 26 human lower limbs (10 men and 16 women) with a mean (± SD) age of 81 ± 12 and range of 53–98 years. The longitudinal ultrasound velocity of the cortical bone at the anteromedial midtibia (tUV, meters per second) was assessed in the intact legs (SoundScan 2000, Myriad Ultrasound, Rehovot, Israel). Then, a cylinder of cortical bone was removed from the anterior tibia at the site of QUS scanning, scanned using peripheral quantitative computed tomography to determine bone density, and mechanically tested in tension to failure. We found that tUV of the intact legs correlated strongly with bone density of the cortical bone specimens ( r 2 = 0.74, p < 0.0001). Both bone density ( r 2 = 0.89, p < 0.0001) and tUV ( r 2 = 0.84, p < 0.0001) were very strongly correlated with the cortical bone elastic modulus. In addition, both tUV ( r 2 = 0.75) and bone density ( r 2 = 0.80) were highly correlated with the ultimate strength of the cortical bone specimens. In summary, tibial ultrasound velocity measured in situ correlated with the material properties of tibial cortical bone nearly as strongly as did bone density.