Increased fatigue resistance of metals by metastable phase transformations

The beneficial effect of metastable phases to overcome the common strength-ductility trade-off during static loading has been demonstrated for a range of different alloys.

However, the fatigue behaviour of metastable materials has been only rarely studied with both positive and negative effects reported depending on alloy system and process condition.

Some preliminary studies by the applicant clearly indicate a considerable improvement in fatigue resistance if the metastable phase transformation can be controlled in an optimal way, i.e. the transformation should takes place in the right place at the right time.

This is indeed a very promising but also challenging for route to develop extremely fatigue resistant materials that can be used to increase the fatigue life of structural components.

Therefore, the fatigue behaviour of metastable alloys needs to be explored further to utilize the full potential of this effect on the fatigue resistance.The aim of this project is to get a deeper understanding of the deformation and fatigue damage mechanism active in metastable materials and to establish strategies and modelling tools that can be used to enhance the fatigue resistance of metals by controlling the metastable phase transformation.