## 4 Discussion  
To investigate if the AM processing parameters would impact resulting magnetic properties, DED samples of different build parameters were created and the same SOQ, MA and FHT were completed on all of the samples of the same composition. Overall, as the AM parameters varied, no large shift occurred in the final magnetic properties in the full-Co alloy nor in the Co-lean alloy (see Table 9; Table 10), with the exception of the full-Co B-2 sample. The lack of strong texture in both compositions of the as-printed DED samples is also likely a source of the consistent magnetic properties across AM processing parameters. Possible minor \(<\)001\(>\) texturing could be the reason why the full-Co B-2 sample had superior magnetic properties; however this would have to be concluded with destructive analysis (i.e., cross section and polishing) of the B-2 sample. It is worth noting that during the SOQ process of both alloys that were built by DED, accelerated, uniform grain growth occurred in both the Co-lean and full-Co. The grain growth that was observed is likely a product of residual stresses in the as-printed specimens. This uniform grain growth is beneficial for the coercivity since larger grains would suppress the total volume of grain boundaries present, limiting the total \(\gamma\)-phase that could form during the MA heat treatment [6]. Future, more complete investigation of the SOQ parameters will be conducted to reach larger grain sizes. Additionally, powder-based alnico magnets can achieve enhanced texture control in the presence of uniform uni-axial stress, thus future investigations could be attempted to utilize the residual stresses from the as-printed state to promote the texture of the post-SOQ microstructure in the desired \(<\)001\(>\) direction [33]. If a \(<\)001\(>\) texture could be developed utilizing the preexisting residual stress, the DED AM method could be part of a logical approach to fully textured alnico magnets. The challenges of build cracking, porosity and defects seen in some materials processed via DED were not evident in these sets of alnico samples. Two different compositions were successfully built over a range of processing parameters, albeit some parameters resulted in qualitatively better builds. Other advanced systems and controls, including laser PBF, could be applied to further optimize the build quality and microstructure of this alnico family of permanent magnet materials, which have proven their potential for being processed by the laser DED method of AM. The focus of most EBM/PBF AM process development research is on the combination of melting parameters (beam speed, power, overlap, etc.) that will lead to dense components. The significant influence of spot size variation on local energy density across the build area, which is difficult to directly measure in situ, is generally not known but can be inferred from corresponding variation in density associated with the known effects of changes in beam focus. Similarly, the preheating parameters are rarely reported. In EBM/PBF the transfer of energy and charge from the beam to the powder bed are  
Figure 19: Coercivity and remanence of the EBM/PBF run#5 samples as a function of hold length for different MA temperature. FHT were kept identical between all samples. inherently coupled. Without sufficient dissipation of charge and adequate preheating, electrostatic repulsion will overcome the mass of discrete adjacent powder particles causing a catastrophic scattering of charged powder throughout the build chamber (i.e., \"smoking\"). Within the powder bed the objective is for the powder to be lightly sintered (i.e., the initial stages of necking). This both dissipates charge by forming an electrically conductive pathway to ground within the powder bed and by providing mechanical resistance to electrostatic repulsion by powder charging. Thus, preheating to have the proper amount of light sintering is necessary to maintain process stability.