A Systematic Study of Sample Preparation-Induced Martensitic Phase Formation in 304L Austenitic Stainless Steel

Published

September 4, 2026

Author(s)

Xingshuo Zhang, Anish Rajan, Matthew Luebbe, Fan Zhang, Haiming Wen

Abstract

Routine sample preparation may unintentionally induce martensitic transformation on the surface of metastable 304 L stainless steel, potentially affecting accurate microstructural characterization. This study systematically investigates the effects of common sample preparation methods such as mechanical cutting, electrical discharge machining (EDM), grinding, and polishing on deformation-induced martensitic transformation on the surface of 304 L stainless steel. Using in-house X-ray diffraction (XRD) and synchrotron-based high-energy XRD, we demonstrate that martensitic transformation is confined primarily to the near-surface region and strongly influenced by the interplay between strain rate and temperature. Mechanical cutting promotes α′-martensite formation with increasing strain rates, whereas thermal effects arising from cutting can suppress transformation by elevating surface temperature above the upper temperature limit for deformation-induced martensite formation. Depending on the preparation route, the measured surface α′-martensite fraction varied from nearly undetectable levels to approximately 0.453. EDM introduced approximately 0.137 vol fraction α′-martensite, likely due to local thermal shock and residual stresses within the resolidified layer. Grinding generated substantial surface α′-martensite because of severe plastic deformation, resulting in α′-martensite volume fraction of 0.286 following mechanical cutting and grinding. In contrast, fine and prolonged polishing largely removed the transformed surface layer, reducing the α′-martensite volume fraction to approximately 0.020 and thereby minimizing its influence on microstructural characterization. These findings emphasize the critical role of sample preparation protocols in accurately characterizing metastable stainless steels. The study provides practical guidelines to minimize preparation-induced artifacts, thereby improving reliability in surface-involved characterizations/investigations.

Citation

Materials Characterization

Pub Type

Journals

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Citation

Zhang, X. , Rajan, A. , Luebbe, M. , Zhang, F. and Wen, H. (2026), A Systematic Study of Sample Preparation-Induced Martensitic Phase Formation in 304L Austenitic Stainless Steel, Materials Characterization, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=960778 (Accessed September 13, 2026)

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