Metallic thin film fatigue dominated by interface character

Metallic thin films are used in many applications like sensors and micro electronic mechanical sensors (MEMS) where they are often subjected to cyclic loading. Due to their low thickness in the range of several nanometers to a few micrometers the properties and failure mechanisms of thin films are different comparing to bulk material. The interface character plays an dominant part in how fatigue damage and failure occurs in thin films. The interfaces between thin film and substrate can be considered as hard (thin film on metal or ceramic substrate), soft (thin film on polymer) or free-standing (thin film without substrate).

Different micromechanical test – like bulge test, X-ray diffraction and transmission electron microscopy – will be used to investigate the role of the interface character on the fatigue properties of thin films. Furthermore, the results are modelled to design criteria for fatigue-restistant metallic thin films.

This project is funded by the DFG and in collaboration with the Erich Schmid Institute Leoben.