## 5 Conclusions  
Hot working is an effective technique for shaping and achieving microstructural control in metallic alloys. However, the most advantageous parameters to achieve the desired microstructure and properties must be established to improve product performance. In addition, these parameters are important for producing semi-finished and finished components with reproducible microstructures and properties. In this study, the combination of parameters for breaking as-cast dendritic structures in two grades of low-density stainless steels, Fe-30.9 Mn-4.9 Al-4.5 Cr-0.4C and Fe-21.3 Mn-7.6 Al-4.3 Cr-1C, was investigated. There is rarely any study considering the hot working of Fe-Mn-Al-C low-density steel with initial dendritic microstructure. Understanding the relationship between deformation parameters and microstructural evolution could enhance processing steps and improve alloys' overall performance. Based on this study's results, the following conclusions are made:  
1. The flow behavior of the two alloys, Fe-30.9 Mn-4.9 Al-4.5 Cr-0.4C and Fe-21.3 Mn-7.6 Al-4.3 Cr-1C, was generally similar to that of most metallic alloys with positive strain rate sensitivity because flow stress increased with decreasing deformation temperatures and increasing strain rate.
2. The complete breakdown of dendritic features can be achieved at deformation temperatures of 800 and 900 \({}^{\circ}\)C and strain rates of 0.1 and 5 s\({}^{-1}\) in both alloys.
3. The breakdown of dendritic structure at 1000 \({}^{\circ}\)C was dependent on strain rate, especially in the austenitic-grade Fe-21.3 Mn-7.6 Al-4.3 Cr-1C low-density stainless steel where 0.1 s\({}^{-1}\) was effective, but 5 s\({}^{-1}\) retained the dendritic structure.
4. Dynamic globularization of ferrite and DRX of austenite grains were identified as the dominant softening mechanisms in duplex Fe-30.9 Mn-4.9 Al-4.5 Cr-0.4C low-density stainless steel except at 1000 \({}^{\circ}\)C at 0.1 s\({}^{-1}\) where dynamic recovery dominated.
5. Dynamic recovery controlled the softening of austenitic-based Fe-21.3 Mn-7.6 Al-4.3 Cr-1C low-density stainless steel, but few globular austenites were seen at 800 and 900 \({}^{\circ}\)C, indicating that some dynamic globularization still occurred.
6. Hot working under all conditions improved the hardness of both alloys owing to the reconstitution and refinement of the microstructural constituents.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app13042310/s1](https://www.mdpi.com/article/10.3390/app13042310/s1)]([https://www.mdpi.com/article/10.3390/app13042310/s1](https://www.mdpi.com/article/10.3390/app13042310/s1)), Figure S1: Fitting corrosion in the dendritic region of low-density stainless steel.  
[PERSON] conducted the experimental analysis and wrote the first draft of the manuscript; [PERSON] co-supervised the work and contributed to funding acquisition; [PERSON] co-conceptualized and co-supervised the study, contributed to funding acquisition, writing, reviewing, and editing the manuscript; [PERSON] co-supervised and contributed to funding acquisition; [PERSON] co-conceptualized and supervised the study, and contributed to funding acquisition as the principal applicant, writing, reviewing, and editing the manuscript. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Faculty Research Council of the University of the Witwatersrand, South Africa.  
Not applicable.  
The raw data obtained from the experiments will be made available on request to readers.  
The authors acknowledge [PERSON] of MINTEK, who is now late, for his assistance with casting the alloys.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.