Chemically Induced Phase Transformation in Austenite by Focused Ion Beam

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 45; no. 3; pp. 1189 - 1198
• Main Authors: Basa, Adina, Thaulow, Christian, Barnoush, Afrooz
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-03-2014; Springer; Springer Nature B.V
• Subjects: Applied sciences; Austenite; Austenitic transformations; Characterization and Evaluation of Materials; Chemistry and Materials Science; Exact sciences and technology; Ferrite; Ion beams; Ions; Materials Science; Metallic Materials; Metallurgy; Metals. Metallurgy; Nanotechnology; Phase transformations; Phase transitions; Physical metallurgy; Plastic deformation; Structural Materials; Surfaces and Interfaces; Thin Films; Transformations; Ferrite; Duplex Stainless Steel; Martensite; Austenite Phase; Austenite; Ion beam; Phase transformation
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-013-2101-4

A highly stable austenite phase in a super duplex stainless steel was subjected to a combination of different gallium ion doses at different acceleration voltages. It was shown that contrary to what is expected, an austenite to ferrite phase transformation occurred within the focused ion beam (FIB) milled regions. Chemical analysis of the FIB milled region proved that the gallium implantation preceded the FIB milling. High resolution electron backscatter diffraction analysis also showed that the phase transformation was not followed by the typical shear and plastic deformation expected from the martensitic transformation. On the basis of these observations, it was concluded that the change in the chemical composition of the austenite and the local increase in gallium, which is a ferrite stabilizer, results in the local selective transformation of austenite to ferrite.