Abstract
Previous studies have indicated the possibility of using ultrasonic attenuation as a nondestructive tool for predicting fracture toughness of metals. In all these studies, the fracture toughness was varied by changing the microstructure or composition. In the present paper, ultrasonic attenuation measurements and an ultrasonic frequency spectrum analysis were conducted on a sample of constant microstructure (AISI 4137 steel) in which the fracture toughness is changed through a tempering process. Results show that within the frequency range considered, frequency dependence on attenuation does not correlate with changes in fracture toughness. Using the frequency spectrum analysis technique, however, possible correlations were found between the upper half power point on the FFT (Fast Fourier Transform) output and the fracture toughness values, in conjunction with the yield strength.
McGrath, Scott Phillip (1997). Using ultrasonic techniques to predict fracture toughness of AISI 4137 alloy steel. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1997 -THESIS -M325.