“…Aging at 1073K results in precipitation of both y' and M 23 C 6 • The heat treated specimens were made plane parallel to within ± 3 pm after removing the oxide layer. Ultrasonic velocity measurements by cross correlation technique [7,8) were carried out using 5, 8.8 and 13 MHz longitudinal and 5 MHz shear waves. The measurement procedure is the same as that reported by Panakkal et al [8].…”