Additive manufacturing (AM) distinguishes itself in materials engineering by its exceptional capacity
for processing metals under diverse conditions. This transformative technology allows for precise
layer-by-layer fabrication of intricate metal structures directly from digital models. This uniqueness
not only facilitates the creation of complex geometries but also enables tailored mechanical
properties. To harness AM's ability to optimize metal structures under varying processing conditions
enhances material efficiency and reduces waste, contributing to cost-effectiveness, is vital to reduce
post processing steps such as heat treatments. Therefore, in this work we investigated the short-range
ordering (SRO) phenomena in additively manufactured highly alloyed steels and multi-principal
element alloys (MPEAs), with the objective of reducing the amount of post processing required, by
optimizing as-built microstructure.
Using the DED-LB process, augmented by controlled substrate preheating, X110MnAl30-8 HMnS
samples were manufactured. The additional layer of control over the process temperature, allowed
for formation of κ-carbides, and thereby SRO, directly during deposition. This strategy eliminates the
need for separate heat treatment steps and enables tailored control over the distribution and
morphology of κ-carbides, thereby improving the mechanical properties. Furthermore, the occurrence
of the strain-age-cracking mechanism, commonly seen in Ni-based alloys, was observed during
manufacturing, posing challenges but also opportunities for increased robustness in AM processes.
In similar fashion, SRO phenomena in the CoFeMnNiAlC MPEA were investigated during the PBF-LB
process. MPEAs present a unique combination of elements that can exhibit complex ordering
phenomena at the atomic scale. Our work sheds light on the intricate atomic arrangements within the
alloy matrix and their correlation with the mechanical properties. The findings provide valuable
insights into tailoring the SRO in CoFeMnNiAlC alloys through additive manufacturing, offering a
pathway for optimizing material performance for applications in advanced structural components. In
this case high solid solution strengthening, high dislocation density and SRO resulted in an as-built
single phase fcc material, boasting 1.1 GPa in tensile strength, while retaining 13% total elongation.
Both results display interesting and promising avenues for furthering the potential of additively
manufactured alloy systems by incorporating microstructure design down to atomic scale.