Selective laser melting (SLM) is an established additive manufacturing process
which can manufacture intricate parts with almost full density. The competitive
advantages of the process are potential of customization as well as design
optimization for light-weighting. The current state of the art recommends that
utilization of the technology can now be extended from rapid prototyping to serial
production for functional applications. Employment of the technology for
functional applications requires not only the resulting density higher than 99%;
reliability of the structures under mechanical loading is the most important
parameter. To ensure reliability, influence of the processing and post-processing
conditions needs to be understood. As many of the applications of SLM process
are in automotive and aerospace industries, fatigue reliability of the parts plays the
foremost role.
This study focuses on the investigation of process chain on the material properties
and the corresponding mechanical behavior. Metallographic techniques like light
and electron microscopy, non-destructive micro-computed tomography are
employed to investigate the material structural properties which are then used to
comprehend the mechanical behavior in quasistatic, high cycle fatigue (HCF),
very high cycle fatigue (VHCF) as well as in crack propagation. Role of processinduced microstructure and defects in fatigue reliability has been discussed, and a
fatigue prediction methodology has been developed based on cyclic deformation
behavior, statistical analysis of defects and finite element analysis. Additionally,
realizability of manufacturing hybrid structures and their influence on part
reliability is also investigated.
The results indicate that the quasistatic strength of SLM-processed AlSi12 alloy is
higher than that of cast alloy due to process-specific structural features, and the
individual processing conditions need to be customized according to the required
properties. For fatigue testing, combined load increase tests with continuously
varying amplitude and constant amplitude tests help expediting the optimization
procedure. SLM can be used for generation of parts with localized properties.
Combination of conventional and additive manufacturing can be successfully
carried out with appropriate post-processing. The developed fatigue prediction
methodology can be applied for SLM structures to help reduce testing effort.
Finally, the essential aspects, still need to be investigated to fully exploit the
potential of SLM technology, are highlighted.