Analysis of Phase Transformations and Structural Properties in Stainless Steel 316L Powder

Abstract

Using X-Ray Diffraction (XRD), this research characterized phase contents and structural validity of SS316L stainless steel powder. SS316L features enhanced corrosion resistance, mechanical strength, and heat tolerance making it a universal selection across challenging environments. XRD identified SS316L powder crystallographic structure and also identified any unwanted secondary phases that may negatively impact its capability to function in actual world applications.The XRD pattern of the powder included 3 distinct peaks at 2? = 43.5°, 50.6°, and 74.6° for the (111), (200), and (220) planes of a face centered cubic (FCC) crystal structure indicating it is in the austenitic phase (?-Fe). The three distinctive peaks likewise imply no undesirable secondary phases (ferrite, sigma phase, or chromium carbides) existed meaning high structural integrity in the powder.The structural integrity of the SS316L powder is vital, considering its value addition in the form of corrosion resistance, mechanical stability over a wide service performance, and performance dependability for use in applications such as; biomedical implants and aerospace parts. XRD results support the SS316L powder can and will work for additive manufacturing, and other high-performance fabrication performance-based processes wherein structural integrity is the priority. Thus, XRD analysis offers itself as a useful tool for verification of powder phases and quality control for high performance engineering metal powders as additive manufacturing increases in popularity.

Introduction

1. Overview of SS316L

• SS316L is a low-carbon austenitic stainless steel known for:

  • Excellent corrosion resistance

  • High mechanical strength

  • Good weldability

• Commonly used in biomedical, aerospace, marine, and chemical industries.

• Its performance depends heavily on its microstructure, especially the presence of the austenitic (γ-Fe) phase with a face-centered cubic (FCC) crystal structure.

2. Importance of Phase Purity

• In additive manufacturing (AM) methods like Selective Laser Melting (SLM), the powder quality is critical.

• The presence of undesirable secondary phases (e.g., ferrite, sigma phase, chromium carbides) can:

  • Lower corrosion resistance

  • Reduce ductility

  • Compromise mechanical performance

3. Purpose of the Study

• To verify the phase purity of SS316L powder using X-Ray Diffraction (XRD).

• Ensure the presence of only the austenitic FCC phase and no secondary phases before powder is used in AM.

4. Methodology

• XRD analysis conducted using Cu Kα radiation (λ = 1.5406 Å).

• Scanning range: 2θ = 20° to 100°

• Setup: Bragg–Brentano geometry (θ–2θ configuration)

• Resolution: 0.02° step size, 1–2°/min scan pace

• Objective: Detect γ-Fe (FCC) peaks and check for absence of secondary phases.

5. Results

• Three strong XRD peaks were observed at:

  • 43.5° → (111) plane

  • 50.6° → (200) plane

  • 74.6° → (220) plane

• All peaks match the FCC (γ-Fe) austenitic structure.

• No signs of secondary phases like ferrite, sigma, or carbides.

• Indicates high structural purity and excellent crystallinity of the powder.

Conclusion

X-Ray Diffraction (XRD) analysis was utilized in this study to characterize the phase composition and crystallographic structure of SS316L powders, a commercially available material that is used in high-end industries (biomedical, aerospace, and additive manufacturing). All three obtained XRD representative diffraction peaks of the SS316L powder occurred at 2? values of 43.5° 50.6°, and 74.6°, which respectively are related to the (111), (200), and (220) planes of a FCC structure, indicating that the material is in a stable austenite (?-Fe) form. More importantly, there were no other secondary phases (ferrite, sigma phase, or chromium carbides) observed, indicating structural purity and overall quality of the SS316L powder. The absence of these detrimental phases supported the materials known advantages; including corrosion resistance, mechanical integrity, and soundness at elevated temperatures, meaning the material is suitable for high performance and precision reliant applications.

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Copyright

Copyright © 2025 Pragya Srivastava, D. P. Singh, Rohit Srivastava. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.