Structural relaxation and defect dynamics in Fe<sub>92</sub>Si<sub>6</sub>C<sub>2</sub> amorphous alloys under controlled annealing

Samadov S. F., Abdullayev A., Abiyev A. S., Ahmadov V. I., Sidorin A. A., Trung N. V. M., ...More

JOURNAL OF MATERIALS SCIENCE, vol.61, no.7, pp.4668-4682, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 61 Issue: 7
  • Publication Date: 2026
  • Doi Number: 10.1007/s10853-025-12132-6
  • Journal Name: JOURNAL OF MATERIALS SCIENCE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, MEDLINE, Public Affairs Index
  • Page Numbers: pp.4668-4682
  • Azerbaijan State University of Economics (UNEC) Affiliated: No

Abstract

This study investigates the defect evolution, structural relaxation, and crystallization behavior of Fe92Si6C2 amorphous alloys subjected to controlled thermal annealing between 373 and 973 K. A multi-technique approach-Doppler broadening spectroscopy (DBS), positron annihilation lifetime spectroscopy (PALS), X-ray diffraction (XRD), and Raman spectroscopy-was employed to analyze the temperature-dependent transformations in free volume, vacancy clusters, and carbon bonding structure. DBS measurements revealed a systematic reduction in free-volume-type defects up to 573 K, followed by nanocrystalline alpha-Fe(Si) nucleation at higher temperatures. PALS analysis showed a decrease in tau 1 and tau 2 lifetimes and a significant increase in I2, confirming the growth of vacancy clusters and defect migration toward grain boundaries during crystallization. XRD confirmed the transition from an amorphous halo to well-defined crystalline peaks, accompanied by a substantial reduction in microstrain from 604 x 10-4 to 17 x 10-4 with annealing. Raman spectroscopy indicated enhanced graphitization and the emergence of a D2 band above 773 K, evidencing structural reorganization of carbon. Overall, the findings provide a comprehensive understanding of defect dynamics and structural evolution in Fe92Si6C2 amorphous alloys, highlighting the effectiveness of thermal treatment in improving their structural integrity and potential for advanced magnetic and technological applications.