Torsion Pendulum Method Research Articles

Effect of Aging Treatment on Damping Capacity in Mncunife Alloy

M2052 alloys with various aging treatments are obtained in order to investigate the relationship between aging treatment and damping capacity by the torsion pendulum, X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results show that M2052 can obtain high damping capacity (δ>0.2) when aged at a range from 400°C to 450°C, and the damping capacity after aged at a lower temperature is higher than that aged at a higher temperature for the maximum values. TEM and XRD results show that fcc-fct transformation occurs after aging treatment. The volumes of fct structures are one of reason to affect the damping capacity in M2052 alloy. The better understanding aging treatment could promote the applications of M2052 alloy.

Investigation of Damping Characteristics of Metals by the Use of Inverted Torsion Pendulum Method

Damping characteristics of metals are measured by the use of inversed torsion pendulum method. As the materials, aluminum alloys, magnesium alloys, Inconel etc are used with the temperature and frequency parameters. Mild steel is employed as a reference material for calibrating the apparatus. The measured damping coefficient of magnesium alloys is larger than that of aluminum alloys indicating that the HCP crystal structure has more damping effect than the FCC structure. The damping of these metals increases with temperature. The manner of increment of damping is investigated to analyses the microscopic mechanism of damping.

Surface tension and viscosity of the molten (LiF–NaF–KF)eut–K2ZrF6 system

Surface tension and viscosity of the system (LiF–NaF–KF)eut–K2ZrF6 were measured in its entire concentration range. Surface tension was measured by the maximal bubble pressure method, and viscosity was measured using the computerized torsion pendulum method. Concentration dependencies of both quantities were calculated for three selected temperatures T = 1,123, 1,173, and 1,223 K on the basis of the experimental data. The values of the surface tension lie in the region 96–160 mN m−1 and the values of the viscosity are in the region 0.86–3.06 mPa s.

1413 倒立型ねじり振り子試験機を用いたニッケル基超合金の粘弾性挙動に関する研究(OS15-3 諸観点からの物質・材料の特性評価III,OS15 諸観点からの物質・材料の特性評価)

Nickel-based superalloys are widely used as the heat-resistant materials in various engineering fields. Therefore, it is very important to clarify the viscoelastic properties of these materials because they are often used under elevated temperatures. The final object of this study is to clarify the viscoelastic constitutive relation of Inconel 718 which is one of the most popular nickel-based superalloys. As the preliminary research for this final object, the internal friction (logarithmic decrement) has been measured by the inverted torsion pendulum method with changing the atmospheric temperature. Prior to the measurement, three types of specimens with different grain sizes were prepared by changing the annealing temperature. As the results, it has been clarified that the logarithmic decrement of the large grain size superalloy is smaller than that of the small grain size superalloy and that in some cases, the logarithmic decrement takes a peak value at the atmospheric temperature of approximately 820-850K.

Product Design Aspects for Design of Accurate Mass Properties Measurement System for Aerospace Vehicles

Mass properties of aerospace vehicle viz Weight, Center of Gravity (Xcg, Ycg, Zcg) & Mass Moment of Inertia (Ixx, Iyy & Izz) are critical inertial parameters which are vital to meet the intended mission objectives. Accurate mass properties measurement is needed for fast maneuvering aerospace vehicles to meet the Control and Guidance requirements within the tolerable limits generated by the System Designer. Mass properties estimation is vital during the configuration design phase of an aerospace vehicle. Assumptions and Constraints during the configuration design, limits the accuracy of estimations making the mass properties measurement mandatory. The mass properties of the aerospace vehicle can be measured by numerous methods, but for achieving high accuracies within the tolerable limits, the measurement system should have advanced technologies and measurement methodologies. Based on the experience, mass properties measurement systems were designed using Load Cells and Cross-Flexural Pivots in two different systems (Weight and CG in System-1, MOI in System-2), which have limited accuracy and also involves tedious external measurements. Adopting Air-Bearing (T / H / Spherical shape) supported with accurate sensors using Inverted Torsion Pendulum method, Multiple Point Weighing method and a proper measurement methodology, enhances the accuracy of the measurement system. Usage of spherical bearing yields a better accurate system but has the difficulty in realization of the system indigenously, whereas use of T or H-shape bearing is a feasible solution for achieving the desired accurate mass properties specifications. This paper gives an insight into to the product design aspects to be considered for realization of accurate mass properties measurement system.

Internal friction measurement of Zr0.8R0.2O1.9 ceramics (R=Y, Sm, and Nd)

The internal friction in three cubic zirconias, Zr0.8R0.2O1.9 where R=Y, Nd and Sm, was compared in the temperature range of 30-400°C using forced torsion pendulum method. The internal friction of Zr0.8Y0.2O1.9 was characterized to two peaks, however that of Zr0.8Sm0.2O1.9 were shown with low amplitude of high temperature peak, as well as that of Zr0.8Nd0.2O1.9 was shown as a single peak at around 100-300°C at 9Hz. The comparative result suggests the effect of the larger cation doping to cubic zirconia, which induced to suppress some kind of oxygen relaxation in cubic fluorite structured zirconia.

239 竹の減衰特性のねじり振動法による測定(生体・環境適合型材料の創製と特性評価(2),ものづくりにおける基礎研究と先端技術の融合)

The viscous characteristics of bamboo is experimentally studied. Attenuation of the free oscillation is measured in inverted torsion pendulum method. The damping of bamboo is compared with that of steel.

Effect of solution treatment on damping capacity and shape memory effect of a CuAlMn alloy

Abstract The effect of solution temperature on martensite transformation temperatures, damping capacity and shape memory effect of a Cu–7.66Al–9.52Mn alloy was investigated by resistivity–temperature method, reversal torsion pendulum method and bend test. The results showed that with increasing temperature, the transformation temperatures and shape memory effect first remarkably increased and then almost remained constant. The damping capacity significantly increased with temperature up to 1098 K and then decreased. The damping capacity was dependent on not only the amount but also the thickness of the martensite plates, while the shape memory effect was mainly determined by the amount of the martensite.

Internal friction of polycrystalline Zr 0.8R 0.2O 1.9 (R = Nd, Y)

The oxygen relaxation in two cubic zirconias, Zr 0.8R 0.2O 1.9 where R = Nd and Y, was compared with internal friction in the temperature range of 300–685 K using forced torsion pendulum method. The internal friction of Zr 0.8Nd 0.2O 1.9 was shown as a single peak at around 350–450 K at frequencies of 0.32–9 Hz. The activation enthalpy of relaxation in Zr 0.8Nd 0.2O 1.9 was determined to be 1.12 ± 0.1 eV. The amplitude of the high-temperature peak in Y-doped zirconia was not observed for Zr 0.8Nd 0.2O 1.9. The result suggests that the relatively lower mobility of oxygen is due to the doping of larger Nd cation to ZrO 2 lattice.

Vibration damping of high-chromium ferromagnetic steel and its dependence on magnetic domain structure

The aim of the present work is to study the vibration damping capacity of annealed high-chromium (16%) ferromagnetic steel. The alloys were prepared from raw materials of 99.9% purity melted in a high frequency induction furnace under high vacuum. The samples were heat-treated in vacuum at various temperatures (800–1200 °C) for 1 h followed by slow cooling (120 °C/h). The duration of 1 h considered was the same for all the specimens and no other duration was considered for evaluation. The inverted torsional pendulum method was used to evaluate the vibration damping capacity. The results indicated that the vibration damping capacity of the alloys is influenced by annealing and there exists a critical annealing temperature after 1000 °C. When the alloy is annealed over the critical temperature, the size of the magnetic domains becomes larger so that the domain wall area in metal decreases, making the damping capacity decrease as well.

Phase Equilibria, Volume Properties, Surface Tension, and Viscosity of the (FLiNaK)eut + K2NbF7 Melts

Physicochemical properties of the system (FLiNaK)eut (1) + K2NbF7 (2) were investigated. Phase equilibria were studied by a thermal analysis method. Density of the investigated system was measured by the Archimedean method. On the basis of these data, molar volumes were calculated for selected temperatures, and the partial molar volume of K2NbF7 in (FLiNaK)eut was evaluated adopting the value V̅2/cm3·mol−1 = (121.1 ± 0.4) at 1073 K, indicating volume contraction. Surface tension was measured by the maximal bubble pressure method, and viscosity was measured using the computerized torsion pendulum method.

Dynamic visco-elastic analysis of silicone maxillo-facial prosthetic material using custom-made dynamic visco-elastometer and LASER measuring device

Purpose : The dynamic mechanical properties of silicone maxillo-facial prosthetic material are very important for the successful rehabilitation of patients with facial defects. Moreover, it is equally important to determine these properties under conditions similar to those observed in the natural movement of facial tissues. This study evaluates the dynamic mechanical properties of silicone maxillo-facial prosthetic material using the classical Torsional pendulum method and high precision laser based measurement system. Materials and Methods : Five commercially available silicone maxillofacial prosthetic materials A-2002, A-2186, A-VST-50, A-588V-1and MDX4-4210 were taken as sample in the form of cylinders measuring 8X80 mm. A custom-made dynamic visco-elastometer was used to determine the Storage modulus, Loss modulus and Loss tangent over a frequency range of 0.5 to 1.0 Hertz at 37΀Celsius. Results : A-VST-50, A-588V-1 had low loss tangent (P less than 0.05), further they had lower storage modulus than other tested material, which is an added advantage over MDX4-4210 and A-2186. At all test frequencies A-2002 was found to have the highest loss modulus as well as the highest loss tangent (damping factor) among all the five kinds of material tested (P less than 0.05) which indicates its slow response to load but large capacity to absorb energy. Conclusion : Custom-made dynamic visco-elastometer has proved to be reliable, low cost and a convenient instrument to evaluate silicone maxillo-facial prosthetic material. No single material was found to have all the desirable dynamic mechanical properties necessary for maxillo-facial prosthesis applications. Therefore, layering of two or more such kind of materials is recommended to achieve desirable properties.

Evaluation of the mechanical spectrum of the deposited materials in a composite system in torsion pendulum

Previously, an approximate way to subtract the mechanical spectra (complex Young's modulus) of deposited materials from a composite reed vibration was proposed [X. N. Ying, Physica B 387, 376 (2007)]. In this article, the way of subtraction of mechanical spectra of deposited materials was extended to the complex shear modulus by a composite torsion pendulum method. Previous approximate formulas to calculate the mechanical spectra of deposited materials were found still to be valid except that new parameters were used. This deduction shows that previous approximate formulas are very applicable in the mechanical spectrum measurement. At last, the experimental result of glycerol was shown in approximate formulas.

Concentration dependence of Fe segregation near the surface in V-Fe alloys after V+ ion irradiation

The effect of Fe segregation near the free surface of V model alloys containing 2, 5, or 7 at % Fe is investigated by x-ray photoelectron spectroscopy. Segregation is induced by 50-keV V+ ion irradiation at a temperature of 30–40°C with fluences ranging from 1019 to 1021. Young’s moduli in these alloys are measured by the torsion pendulum method. The degree of Fe segregation is estimated, and its dependence on the irradiation dose and iron concentration in these alloys is analyzed. Correlation is found between the behavior of Young’s moduli and the degree of iron surface segregation as functions of the Fe concentration in the alloys.

N--H Interaction in Nitrided Fe--Nb Alloys

Internal friction of nitrogen in α iron has known as Snoek peak of N atom resolv ed in the octahedral interstitial site of bcc. When M atom ( Mn, Mo, Si, et.al) which has the affinity bigger than Fe were added ,another peaks due to the jump of N from Fe-Fe site to Fe-M site appear in the upper temperature side and complicate the Snoek peak curve of N. In this paper, the Snoek peak curve was studied in Fe-0.4wt%Nb-0.02wt%N alloys. This alloy showed no other peaks in the upper side to 373K and had only the single peak of N in Fe-Fe site. Internal friction measured by torsion pendulum method at about 1 Hz. After that this alloy was cooled from 373K to room temperature and reheated to 373K, but Snoek peak of N which showed on the first measurement just after nitriding disappeared completely and internal friction was only background. One of the reasons of it is the precipitation of Fe16N2 under heating and resolved N atoms disappeared. So these specimens were reheated to 873K and quenched, but Snoek peak of N was not measured. This shows the disappearance of N atom from Fe-Fe site. The mixture gas of a few % NH3 and H2 was used in this study. Therefore after nitriding much of H atoms were resolved in α iron alloys. Because the diffusion rate of H atom in α iron is bigger than N atom , it expected that H atoms can combine with Nb atoms before coming N atoms. And the appearance of Snoek peak of N in these alloys is considered. After that, in the heating to 373K H atom leave Nb and go away from the surface, and N atoms combine with Nb in place of H atoms. Nb has the very strong affinity with N, so these alloys have no peaks. When they reheated to the nitriding temperature N atoms can not diffuse from Fe-Nb site to Fe-Fe site. Then Snoek peak of N can not appears again in these alloys. Therefore, when Fe-Nb alloys were nitrided in NH3 and H2 mixture gas H atom plays very important part and it needs that the interaction of N-H atoms will be considered in these nitrided Fe-Nb alloys.

Density and Viscosity of the (LiF + NaF + KF)eut (1) + K2TaF7 (2) + Ta2O5 (3) Melts

The density and the viscosity of the melts of the system (LiF + NaF + KF)eut (1) + K2TaF7 (2) + Ta2O5 (3) have been investigated up to x3 = 0.02 and x2 = 0.15. The density of the melts has been measured using an Archimedean method. On the basis of the measured densities, the molar volumes of the melts and the partial molar volume of K2TaF7 in binary (LiF + NaF + KF)eut (1) + K2TaF7 (2) system have been calculated. The viscosity of the melts of the investigated system has been measured using the computerized torsion pendulum method. The viscosity data was fit to modified Redlich−Kister's equation.

Viscosity of the System KF–K2NbF7–Nb2O5

Abstract The viscosity of melts of the system KF–K2NbF7–Nb2O5 has been measured using computerized torsion pendulum method. An equation describing the dependency of the viscosity in logarithm values on composition at 1173 K was calculated by multiple linear regression analysis. The sum of viscosities of pure components in logarithm values multiplied by their mole fraction was used as an “additive” behaviour. In the concept of modified Redlich–Kister's type equation binary interactions of the particular components were found.

Torsional method for evaluating hair damage and performance of hair care ingredients

In this study, we have developed a single hair fiber torsional pendulum method to determine the role of the cuticle and the cortex on torsional properties with respect to fiber cross-sectional area, fiber rigidity, and energy dissipation at 65% RH and in the wet state. Our results demonstrate that in fine diameter fibers with a high cuticle-to-cortex ratio, the cuticula exert a significant effect on the torsional deformation behavior of hair fibers at both normal humidities and in the wet condition. In addition, our data indicate that energy dissipation is confined to fibers with a high cuticle-to-cortex ratio, and the amount of energy dissipated becomes more pronounced with increasing water content. The torsional properties of hair spray-treated fibers suggest that the deposited hair spray film masks the properties of the base fiber and imparts its own dissipative character to the measurement. Since tensile mechanical properties are often used to make claims about the performance of hair care products, we have compared the results obtained from torsional and tensile measurements on over-processed bleached hair fibers conditioned with Polyquaternium-10 and cetyl trimethylammonium bromide (CETAB) to evaluate which method is more advantageous. Our data demonstrate that torsional measurements can distinguish hair care products which reinforce the cuticle from those which affect the cortex, while tensile measurements showed no significant differences.

Structural and thermodynamic aspects in the molybdenum melts of the system KF–K2MoO4–SiO2

The complex physico-chemical analysis of the system KF–K 2 MoO 4 –SiO 2 , based on the phase diagram, density, surface tension and viscosity measurements, was performed. The phase diagrams of the binary systems as well as that of the ternary system in the range up to 50% SiO 2 were measured using the thermal analysis method. The results proved the presence of the congruently melting compound K 3 FMoO 4 at 751 °C in the binary melt KF–K 2 MoO 4 . The strong positive deviation from ideal behaviour of the ternary system KF–K 2 MoO 4 –SiO 2 was ascribed to the formation of heteropolyanions [SiMo 12 O 40 ] 4− in the melt. In the investigated concentration range of the ternary system, no eutectic point has been found. It lies most probably beyond the investigated part of the system. The probable inaccuracy in the calculated ternary phase diagram is 5.9 °C. The density of the melts of the system KF–K 2 MoO 4 –SiO 2 was measured using the Archimedean method. Based on the obtained density data the molar volume, partial molar volume and excess molar volume of the melts were calculated in order to consider the possible chemical interactions of components. The degree of thermal dissociation of the additive compound K 3 FMoO 4 was calculated based on both the thermodynamic analysis of the phase diagram and the volume properties of the investigated system. It was found that the degree of the thermal dissociation of K 3 FMoO 4 at the melting point attains the value α o =0.81. The dissociation enthalpy, calculated on the basis of the density values is Δ H (dis, K 3 FMoO 4 )=18.8 kJ mol −1 . The surface tension of the molten system KF–K 2 MoO 4 –SiO 2 has been determined using the maximum bubble pressure method. Based on the obtained data the concentration dependence of the surface tension and of the surface tension excess of the investigated system was calculated. The viscosity of melts of the system KF–K 2 MoO 4 –SiO 2 has been measured using the computerised torsional pendulum method. The sum of viscosities of pure components in logarithm values multiplied by their mole fraction was used as an ‘additive’ behaviour. A multiple linear regression analysis was performed to obtain coefficients of the modified Redlich–Kister's type equation. Binary and ternary interactions of the particular components were found. X-ray powder diffraction patterns and IR spectra of the certain quenched powdered samples of both binary and ternary mixtures were recorded. By both techniques the presence of starting compounds and the presence of another compounds, as well, was detected. Some of these compounds were recognized based on the known data. The remaining data were attributed to the possible expected compounds.

Structural and thermodynamic aspects in the molybdenum melts of the system KF–K 2MoO 4–SiO 2

The complex physico-chemical analysis of the system KF–K 2MoO 4–SiO 2, based on the phase diagram, density, surface tension and viscosity measurements, was performed. The phase diagrams of the binary systems as well as that of the ternary system in the range up to 50% SiO 2 were measured using the thermal analysis method. The results proved the presence of the congruently melting compound K 3FMoO 4 at 751 °C in the binary melt KF–K 2MoO 4. The strong positive deviation from ideal behaviour of the ternary system KF–K 2MoO 4–SiO 2 was ascribed to the formation of heteropolyanions [SiMo 12O 40] 4− in the melt. In the investigated concentration range of the ternary system, no eutectic point has been found. It lies most probably beyond the investigated part of the system. The probable inaccuracy in the calculated ternary phase diagram is 5.9 °C. The density of the melts of the system KF–K 2MoO 4–SiO 2 was measured using the Archimedean method. Based on the obtained density data the molar volume, partial molar volume and excess molar volume of the melts were calculated in order to consider the possible chemical interactions of components. The degree of thermal dissociation of the additive compound K 3FMoO 4 was calculated based on both the thermodynamic analysis of the phase diagram and the volume properties of the investigated system. It was found that the degree of the thermal dissociation of K 3FMoO 4 at the melting point attains the value α o=0.81. The dissociation enthalpy, calculated on the basis of the density values is Δ H(dis, K 3FMoO 4)=18.8 kJ mol −1. The surface tension of the molten system KF–K 2MoO 4–SiO 2 has been determined using the maximum bubble pressure method. Based on the obtained data the concentration dependence of the surface tension and of the surface tension excess of the investigated system was calculated. The viscosity of melts of the system KF–K 2MoO 4–SiO 2 has been measured using the computerised torsional pendulum method. The sum of viscosities of pure components in logarithm values multiplied by their mole fraction was used as an ‘additive’ behaviour. A multiple linear regression analysis was performed to obtain coefficients of the modified Redlich–Kister's type equation. Binary and ternary interactions of the particular components were found. X-ray powder diffraction patterns and IR spectra of the certain quenched powdered samples of both binary and ternary mixtures were recorded. By both techniques the presence of starting compounds and the presence of another compounds, as well, was detected. Some of these compounds were recognized based on the known data. The remaining data were attributed to the possible expected compounds.