Abstract
Using ultrasonic frequencies offers a possibility to investigate the fatigue properties of materials in a very economic way. High cycle fatigue tests of the die-cast magnesium alloy AZ91 hp were performed. The endurance limit of this material is affected by the maximum size of cast voids and may be predicted on the basis of LEFM-principles. Near threshold constant amplitude and random amplitude fatigue crack growth measurements of metastable austenitic-ferritic steel are presented and interpreted on the basis of crack closure effects.

Key words
ultrasonic frequencies, fatigue properties, austenitic-ferritic steel, LEFM-principles

Full text (2568 KB)