## 5 Conclusions  
In this work, the LPBF processability of the nickel-copper-based alloy (G-NiCu30 Nb/DIN 2.4365) was successfully demonstrated. After varying process parameters between scanning speed and hatch distance, highly dense cubes of relative density of 99.8% were built at both 80 \(\upmu\)m and 140 \(\upmu\)m hatch distances with scanning speeds of 1000 mm/s and 850 mm/s, respectively. No significant difference in microhardness was recorded for both as-built hatch distance print sets (247 HV\({}_{0.2}\) for ys = 80 \(\upmu\)m and 244 HV\({}_{0.2}\) for ys = 140 \(\upmu\)m). This was significantly higher than the as-cast microhardness of 179 HV\({}_{0.2}\) of the same material. PHT resulted in a further drop in microhardness of the as-built cubes to 221 HV\({}_{0.2}\) (80 \(\upmu\)m ys) and 210 HV\({}_{0.2}\) (140 \(\upmu\)m ys) after 1000 \({}^{\circ}\)C for 1 h. Tensile properties of both vertical and horizontal orientation-built tensile specimens showed superior properties to as-cast specimens (UTS 450 MPa, YS 170 MPa, El 25%). The UTS of vertical orientation-built specimen was higher (739 MPa)than that of the horizontal orientation-built specimen (731 MPa) but recorded a lower YS (531 MPa) compared to the horizontal orientation-built specimen (567 MPa). Similarly, anisotropy was observed with regard to the elongation and the building orientation. Elongation was observed to be higher (20%) in the vertical orientation-built specimen than in the horizontal orientation-built specimen (16%). PHT deteriorated both the UTS (674 MPa--V orientation, 665 MPa--H orientation) and YS (408 MPa--V orientation, 417 MPa--H orientation) compared to the as-built condition but also recorded a higher elongation (31%--V orientation, 25% MPa--H orientation).  
Epitaxial growth does not require sufficient nucleation energy for nucleus formation. In additive manufacturing, the growth of epitaxy is associated with remelted areas which typically arise from overlapping melt pools. This phenomenon which also occurs in single-phase alloys leads to the formation of columnar structures which introduces anisotropic properties. Columnar-oriented structures are by their nature coarser than equiaxed structures and may not be fit for use in multipronged stress applications compared to a preferred equiaxed or combination of columnar-equiaxed structures [50]. Further work, therefore, needs to be done to minimize the level of epitaxy to achieve equiaxed or columnar-equiaxed structure necessary for the production of reproducible AM parts with isotropic properties. This could be attained through the introduction of heterogeneous nucleation sites which act as grain refiners and the slowing of solidification speed through in situ heat treatment techniques for nuclei formation.  
After successful LPBF processability, the G-NiCu30 Nb alloy proved to be a good material candidate for AM fabricated components but, however, requires further research to understand and optimize the microstructure for enhanced mechanical properties. This study significantly opens the door for industrial applications of additively manufactured parts from the G-NiCu30 Nb alloy after demonstrating successful LPBF processability. This means that not only does the G-NiCu30 Nb alloy add up to the scope of AM applicable materials, but also that this Monel 400 variant, which according to this study shows very good mechanical properties via LPBF processing, presents itself as an alternative to the cast in the building of convoluted or complex geometrical parts and in the elimination of tooling cost.  
Conceptualization, I.R.; data curation, F.A.-K. and A.H.; investigation, F.A.-K. and A.H.; methodology, I.R.; project administration, I.R.; resources, E.W. and S.B.; supervision, I.R.; validation, U.V.; writing--original draft, I.R. and F.A.-K.; writing--review and editing, I.R., U.V., A.H., and A.B.-P. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors declare no conflicts of interest.