Papers by Keyword: Resonant Ultrasound Spectroscopy (RUS)

Abstract: The structure, thermal stability and elasticity of Zr50Cu40Al10 bulk metallic glass (BMG) have been investigated with reference to Zr70Cu30 and Zr70Cu20Al10 amorphous alloys. The thermal stability of Zr50Cu40Al10 is significantly enhanced in comparison compared with those of the others. The large total coordination numbers more than 11 around all constituent elements are observed in Zr50Cu40Al10. A change of the bulk modulus in the crystallization is extremely small in Zr50Cu40Al10. The present experimental results indicate that atoms in the Zr50Cu40Al10 glass are closely packed and its microstructure is fairly uniform. This results in the much higher thermal stability of Zr50Cu40Al10.

Abstract: Zirconium alloys are used for many applications in nuclear components, such as the pressure tube material in a pressurized heavy water reactor, nuclear fuel cladding, etc. One of the problems during the operation of a nuclear reactor is the degradation of the zirconium alloys, which is due to an increase of the hydrogen content in the zirconium alloy. Therefore a non-destructive determination of the hydrogen concentration in zirconium alloy is one of the important issues that need to be addressed. The resonant ultrasound spectroscopy (RUS) technique is evaluated for a characterization of the hydrogen concentration in Zr-2.5Nb alloy. Referring to the terminal solid solubility for dissolution (TSSD) of Zr-2.5Nb alloy, the plot of the mechanical damping coefficient (Q-1) versus the temperature or the deviation of the resonant frequency for the temperature (df/dT) versus the temperature was correlated for the hydrogen concentration in Zr-2.5Nb alloy. It was found that the temperature at an abrupt change of the slope can be correlated with the hydrogen concentration of the Zr-2.5Nb alloy.

Abstract: This study evaluates cracks in a ceramic ferrule. When an optical fiber is connected to machinery, a ferrule is used to precisely set the optical axes of an optical fiber. A ferrule is a cylinder of 10.5mm in length and 2.5mm in diameter. The crack size of a ferrule can range from 10.40
m to 32.35
m. An acceptable ferrule must have no cracks. In this paper, we predicted and examined defects by Resonant Ultrasound Spectroscopy (RUS). To verify the data obtained from the experiment, we carried out simulation by explicit finite elements method, and compared the experimental results with simulation results. The average error range is 1~2 percent between the experimental resonant frequency of the acceptable specimens and the simulated FEM resonant frequency. Also, we compared the resonant frequencies of specimens with a crack with those of acceptable specimens. The histogram drawn from these data and the available mode surveyed were used to classify the specimens in the plant as either cracked or non-cracked specimens.