Multi-material additive manufacturing allows the preparation of novel hierarchically-structured bulk and composite materials with enhanced properties or property combinations that cannot easily be prepared by conventional processing techniques. This holds for combinations of different classes of materials with tailored length-scale modulation of different phases that can be artificially tuned and distributed throughout the material. Such multi-material hybrid structures can be designed as structurally tuned or functionally graded materials providing an optimized response at specific positions for particular applications. However, due to constraints with the compatibility of different classes of materials and/or phases with different intrinsic properties as well as the need of proper adjustment of interfaces and interphase boundaries, multi-materials additive manufacturing imposes significant challenges on optimized processing in order to avoid building defects, internal stresses or crack evolution, which may deteriorate the otherwise achievable properties of the materials.

In this study, results on (liquid dispersed) laser powder bed fusion of different metals (e.g. combinations of Inconel and steel) without and with micro-/nanoscale ceramic reinforcements (e.g. Al- and Ti-based metal matrix composites reinforced with ZrC, TiC, TiB2, TiN, AlN etc.) will be presented and discussed concerning phase and microstructure evolution under varying process parameter variations. Special emphasis will be placed on possible defects, how they can be avoided or at least minimized, and how the correlation between processing parameters, structure formation and resulting properties can be optimized. These results may be used for a material design approach for creating hierarchically-structured additively manufactured multi-materials and structurally/functionally tailored advanced composites with improved mechanical properties.