| The deformation and fatigue crack growth behavior of amorphous metals are presented. A discussion of magnetic domains, and their influence on magnetostriction is also included. Testing of Metglas 2605SC, utilizing magnetostriction to generate {dollar}Delta{dollar}K, indicated near-threshold (Region I) fatigue crack growth behavior for as-cast and annealed specimens. A {dollar}Delta{dollar}K{dollar}sb{lcub}rm th{rcub}{dollar} on the order of 0.6-1.0 kg/mm{dollar}sp{lcub}3/2{rcub}{dollar} was also indicated. The best crack growth rate behavior was obtained for transverse field-annealed specimens. Significant variability in the data, however, prevented a determination of {dollar}Delta{dollar}K{dollar}sb{lcub}rm th{rcub}{dollar} for this condition. A life prediction model based on a Paris equation was developed. Crack growth data were consistently lower than predicted by the Region II model, which would be expected for near-threshold data. Fractographic analyses supported the influence of domains on crack growth behavior. The scatter in the Region I data appears to be contributed by the effects of domains and domain walls. |
