Self healing of creep damage in iron-based alloys by supersaturated tungsten

When metals are mechanically loaded at elevated temperatures for extended periods of time, creep damage will occur in the form of cavities at grain boundaries. In the present experiments it is demonstrated that in binary iron-tungsten alloys creep damage can be self healed by selective precipitation of a W-rich phase inside these cavities. Using synchrotron X-ray nano-tomography the simultaneous evolution of creep cavitation and precipitation is visualized in 3D images with a resolution down to 30 nm. The degree of filling by precipitation is analysed for a large collection of individual creep cavities. Two clearly different types of behaviour are observed for isolated and linked cavities, where the isolated cavities can be filled completely, while the linked cavities continue to grow. The demonstrated self-healing potential of tungsten in iron-based metal alloys provides a new perspective on the role of W in high-temperature creep-resistant steels.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Novel Aerospace MaterialsRST/Fundamental Aspects of Materials and Energy(OLD) MSE-1QN/Afdelingsburea