Examining with the Sintered Temperature of Mean Grain Size of B₄C-Al-Ni Composites by Ultrasonic Techniques

Abstract

Hard, tough, lightweight boron-carbide-reactive metal composites, boron-carbide-aluminum composites, are produced. The ultrasonic velocity and attenuation were measured on B 4 C-Al-Ni ceramic-metal composites, which are sintered in the temperature range 500-1200• C, by using the pulse echo method. Ultrasonic velocity, ultrasonic attenuation and rate of screen heights of successive peaks were determined according to the pulse-echo method by using 2 MHz and 4 MHz probes. It was observed that the mean grain size of samples has been changed with the sintering temperature. The velocity was found to be pretty sample dependent at room temperature and increased with increasing sintering temperature. The ultrasonic attenuation at room temperature was found to be more sample dependent. The sintering temperature variation of ultrasonic attenuation exhibited broad minimum values around 1200• C and sharp maximum values at 500• C. The increase observed in the temperature variation of longitudinal velocities and attenuation has been qualitatively explained with the help of the temperature variation of decrease value.

Evaluation of mean grain size using the multi-scale ultrasonic attenuation coefficient

“…To verify the effectiveness of the method proposed in this work, it was compared with the traditional velocity evaluation model shown in reference [10] and the traditional attenuation evaluation model shown in reference [12]. Based on the average grain size obtained by metallographic method, the traditional velocity evaluation model is Dðc L Þ ¼ 2316:405 À 0:381c L .…”

“…Attenuation is a frequently used method currently, based on the difference of attenuation of acoustic energy when ultrasound propagates in materials of different mean grain sizes. In application of the attenuation method, not only can the fitting evaluation model based on experiment be established by means of total attenuation coefficient in time domain and average grain size [11,12], but the evaluation model of grain size in the form of power function can be built with the aid of the spectrum of attenuation coefficient in frequency domain [13]. Moreover, there is another method named peak frequency in the amplitude spectrum, which is actually a variation of the frequency dependent attenuation method [14].…”

Influence of heat treatment on the microstructure, ultrasonic attenuation and ultrasonic velocity of GH4169 alloy

“…Ultrasonic attenuation coefficient is sensitive to the average grain size, the grain size increases; the attenuation coefficient increases [4,5,6,7,8]. Sound velocity is affected by grain binding force and residual stress, and is sensitive to content of precipitate [9], precipitated phase [4], phase change [10,11].…”

Correcting the Ultrasonic Scattering Attenuation Coefficient of a Metal Using an Equivalent Medium Layer

“…Therefore, the microstructures of the metals, such as grain size and porosity, can be evaluated by the scattering attenuation coef cient [1][2][3] . However, the coupling and sound eld diffraction can affect the measurement accuracy of the scattering attenuation coef cient in practical applications.…”