High-Frequency Fatigue of Metals and Their Cavitation-Damage Resistance

Abstract

In order to verify the strain-rate effects on the correlation between strain energy of metals and their cavitation-damage resistance, high-frequency fatigue tests at 14.2 kcs were conducted using a magnetostriction oscillator. Utilizing Morrow’s theory, it has been shown that fatigue at this frequency can be quantitatively represented if a 15 percent reduction in static strain-hardening factor is made. This result shows that the strain-rate effects are relatively small (for the metals investigated) when plastic-strain energy is used as a criterion. Another result revealed by this study is the influence of corrosion on high-frequency fatigue and cavitation-damage resistance. Present experiments show that fatigue strength can be reduced significantly for SAE 1020 steel in 3 percent NaCl solution even at high frequencies, thus confirming earlier speculations on this aspect.