Early detection of damage and analysis of damage development in metal structural components

The topics of these short lectures on the subject of cyclic stress were: Microstructural mechanisms of damage accumulation under a multistage cyclic stress until incipient cracking; influence of surface decarbonizing phenomena on the failure behaviour of steel construction parts subjected to cyclic stress; thermocyclic fatigue of pipe samples of austenitic steel 1.4436; studies on surface structuring, microstructure and fatigue in LCF area. The short lectures on effects of quasi-static and creep stress were: Shear fracture in AlMg alloys as a result of local plastic instability; study of formation and growth of pores for an early recognition of damage and the course of damage in heat-resistant steels under creep test; experimental and numeric studies of the infuence of the microstructure on the course of damage during shear fractures of steel; numerical modelling of ductile fractures on the basis of micromechanical models. Under the topic of tribological stress the following lectures were held: Pitting after previous mechanical damage of the testing surface on samples of 100Cr6 and 16MnCr5; radiographic and microscopic studies on the damage when rolling over locally pre-damaged rolling elements; radiographic and metallographic studies of rolling fatigue on locally thermally influenced angular ball-bearing rings; studies on early recognition of damage and on damage-time course of pitting on spur wheels. (orig./MM)