| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1759128 | Ultrasonics | 2013 | 9 Pages |
•In situ thermography in combination with SEM fractography is applied during ultrasonic fatigue testing.•Different fracture types were identified and discussed by this method.•The method enables the exact identification of local crack initiation point as well as the crack propagation path.
The present paper illustrates the application of infrared thermal measurements for the investigation of crack initiation point and crack propagation in the high-cycle and the very high-cycle fatigue range of cast AlSi7Mg alloy (A356). The influence of casting defects, their location, size and amount was studied both by fractography and thermography. Besides internal and surface fatigue crack initiation as a further crack initiation type multiple fatigue crack initiation was observed via in situ thermography which can be well correlated with the results from fractography obtained by SEM investigations. In addition, crack propagation was studied by the development of the temperature measured via thermography. Moreover, the frequency influence on high-cycle fatigue behaviour was investigated. The presented results demonstrate well that the combination of fractography and thermography can give a significant contribution to the knowledge of crack initiation and propagation in the VHCF regime.
