Sathish Shamachary, Martin Richard W
University of Dayton Research Institute, OH 45469-0127, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2002 May;49(5):550-7. doi: 10.1109/tuffc.2002.1002453.
An acoustic microscope operating with impulse excitation has been used to perform measurements of the Rayleigh wave velocity by measuring the time difference between the direct reflected signal and the Rayleigh wave signal. The accuracy and precision of the methodology have been examined by performing measurements at a single location on an elastically isotropic sample of E6 glass. The accuracy of the Rayleigh wave velocity measurement has been determined to be better than 0.5%. The measured Rayleigh wave velocity of (3035+/-5) m/s differs by 0.3% from measurements reported in the literature for a similar sample, using two different techniques. The methodology has been extended to acquire the Rayleigh wave velocity while raster scanning the sample to develop a quantitative velocity image. The background noise in the Rayleigh wave velocity image has been investigated by mapping the velocity on elastically isotropic E6 glass. Possible reasons for background noise in the images is discussed. The methodology has been extended to acquire quantitative Rayleigh wave velocity images on Ti-6Al-4V. The contrast in the images is attributed to the variation of the Rayleigh wave velocity in individual grains or regions. Applicability of the technique to investigate crystallographic texture in materials is discussed.
一种采用脉冲激发的声学显微镜已被用于通过测量直接反射信号与瑞利波信号之间的时间差来测量瑞利波速度。通过在E6玻璃的弹性各向同性样品的单个位置进行测量，检验了该方法的准确性和精确性。已确定瑞利波速度测量的准确性优于0.5%。所测得的(3035±5)米/秒的瑞利波速度与文献中使用两种不同技术对类似样品所报道的测量结果相差0.3%。该方法已扩展到在对样品进行光栅扫描时获取瑞利波速度，以生成定量速度图像。通过在弹性各向同性的E6玻璃上绘制速度图，研究了瑞利波速度图像中的背景噪声。讨论了图像中出现背景噪声的可能原因。该方法已扩展到在Ti-6Al-4V上获取定量瑞利波速度图像。图像中的对比度归因于各个晶粒或区域中瑞利波速度的变化。讨论了该技术在研究材料晶体织构方面的适用性。
