Use of friction stir processing to synthesize nanocrystalline, grain boundary segregating Fe-Ti alloys

Journal Article · Fri May 01 00:00:00 EDT 2026 · Materials Science and Engineering: A

DOI:https://doi.org/10.1016/j.msea.2026.150050· OSTI ID:3030484

Tang, Wei ^[1]; Herbert, Erik ^[1]; Anand, Amrita ^[1]; Boebinger, Matthew ^[1]; Poplawsky, Jonathan D ^[1]; Yang, Ying ^[1]; Perrin, Alice ^[1]

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1. ORNL

Grain boundary segregating alloys, a class of alloys designed such that nanocrystalline grain sizes are thermodynamically stabilized by the presence of high segregation energy solutes at the grain boundaries, are typically produced through geometrically limited processing techniques such as equal channel angular extrusion or thin film sputtering. This study explores the use of friction stir processing (FSP) as a novel means of studying and producing these alloys using a test system of Fe-6at%Ti. Spot FSPs with a range of processing parameter sets were produced on bulk, coarse grained bars of material and optimal parameters were identified. Microscopy identified a range of processed materials which achieved nanocrystalline grains on the order of 100 nm, delineating a critical window of processing parameters which limit heat input while inducing sufficient plastic deformation for grain refinement. The finest grained nanocrystalline Fe-Ti achieved a hardness of 7.68 GPa, a significant increase in hardness over pure Fe with a similar microstructure due to increased dislocation density from FSP as well as several strengthening mechanisms produced through the presence and segregation of Ti. These results demonstrated the feasibility of using FSP to produce nanocrystalline grain boundary segregating alloys.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 3030484
• Journal Information: Materials Science and Engineering: A, Journal Name: Materials Science and Engineering: A Vol. 959
• Country of Publication: United States
• Language: English