## 4 Conclusions  
The investigation conducted in this study aimed to explore the influence of sub-recrystallization and recrystallization temperature during solution treatment on the mechanical performance of LPBF-produced Inconel 939 alloy. The verification of hypotheses provided valuable insights into the behavior of the alloy under varying thermal conditions and shed light on the critical aspects influencing its mechanical properties.  
* Impact of Solution Treatment Temperature on Carbide Redistribution: The analysis confirmed that higher solution treatment temperatures significantly impact carbide redistribution within LPBF-produced Inconel 939 parts. A microstructural examination revealed distinct changes in grain structure and precipitation distribution, particularly the migration of carbides from grain boundaries to intragranular regions. This finding underscores the importance of precise control over heat treatment parameters to achieve the desired microstructural evolution.
* Effect of Solution Treatment Temperature on Mechanical Performance: Contrary to initial expectations, this study found that an increase in solution treatment temperature does not necessarily lead to improved mechanical performance for LPBF-produced Inconel 939 parts. Tensile tests revealed that higher heat treatment temperatures resulted in inferior mechanical properties, particularly in terms of tensile strength at room temperature. The formation of larger recrystallized grains with intragranular carbides in the HT2 state contributed to this decline in mechanical performance.
* Prerequisites for Optimal Mechanical Behavior: This research underscores the importance of precise control over heat treatment parameters to achieve optimal mechanical behavior in LPBF-produced Inconel 939 components. It highlights the need for a comprehensive understanding of the interplay between alloy composition, initial microstructure, and specific heat treatment conditions. This knowledge is essential for guiding future efforts aimed at enhancing the mechanical performance of the alloy.
* Recommendations for Further Studies: Building upon the insights gained from this study, several recommendations for further research are proposed. These include investigating alloy modifications using  
Figure 9: SEM micrographs of Inconel 939 oxidized edges for HT1 state SE detector **(A)**; YAGBSE detector **(B)**; EDS scanning line direction marked with red, with blue graph for weight% of Cr **(C)**; EDS graph for marked line **(D)**; HT2 state SE detector **(E)**; YAGBSE detector **(F)**; EDS scanning line direction marked with red, with yellow graph for weight% of Cr **(G)**; EDS graph for marked line **(H)**.  
elements such as Re and ODS to improve high-temperature performance and optimizing solution treatment times with aging parameters to enhance tensile performance.  
Conceptualization, P.P. and J.M.; Methodology, P.P., D.M. and J.M.; Software, P.P.; Formal analysis, P.P., D.M. and J.M.; Investigation, P.P., D.M., K.P. and M.W.-C.; Data curation, P.P. and D.M.; Writing--original draft, P.P.; Writing--review & editing, D.M., K.P. and J.M.; Visualization, P.P.; Supervision, J.M.; Project administration, J.M.; Funding acquisition, J.M. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Faculty of Materials Science and Engineering, Warsaw University of Technology's subsidy \"Materials for working in extreme conditions\"--2023.  
Not applicable.  
All data included in this study are available upon request by contact with the corresponding author.  
The authors declare no conflicts of interest.