Structural modifications during heating of bulk nanocrystalline FeAl produced by high-pressure torsion

• Published in: Acta materialia Vol. 58; no. 17; pp. 5631 - 5638
• Main Authors: Mangler, C., Gammer, C., Karnthaler, H.P., Rentenberger, C.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2010; Elsevier; Elsevier Science
• Subjects: Aluminides; Applied sciences; Exact sciences and technology; Ferrous alloys; Heating; High-pressure torsion; Intermetallics; Iron aluminides; Iron compounds; Metals. Metallurgy; Microhardness; Nanocrystalline materials; Nanostructure; Ordering; Recovery; Torsion; Transmission electron microscopy (TEM); Ordering; Nanocrystalline materials; Recovery; Transmission electron microscopy (TEM); High-pressure torsion; Transmission electron microscopy; Torsion; Nanocrystal
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2010.06.036

The deformation-induced nanostructure developed during high-pressure torsion of B2 long-range ordered FeAl is shown to be unstable upon heating. The structural changes were analyzed using transmission electron microscopy, differential scanning calorimetry and microhardness measurements. Heating up to 220°C leads to the recurrence of the chemical long-range order that is destroyed during deformation. It is shown that the transition to the long-range-ordered phase evolves in the form of small ordered domains homogeneously distributed inside the nanosized grains. At temperatures between 220 and 370°C recovery of dislocations and antiphase boundary faults cause a reduction in the grain size from 77 to 35nm. Grain growth occurs at temperatures above 370°C. The evolution of the strength monitored by microhardness is discussed in the framework of grain-size hardening and hardening by defect recovery.