Improvement of fatigue properties of duplex-treated ELI Ti6Al4V fabricated by laser powder bed fusion: heat treatment and W-DLC coating under various temperature conditions

Tekdir H., Yetim A. F., Yildiz F., EFEOĞLU İ., GÜLTEN G.

JOURNAL OF MATERIALS SCIENCE, 2026 (SCI-Expanded, Scopus) identifier

  • Yayın Türü: Makale / Tam Makale
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1007/s10853-026-12488-3
  • Dergi Adı: JOURNAL OF MATERIALS SCIENCE
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, MEDLINE, Public Affairs Index
  • Atatürk Üniversitesi Adresli: Evet

Özet

This study investigates the effects of a duplex surface treatment, consisting of sub-beta-transus heat treatment followed by W-DLC coating via closed-field unbalanced magnetron sputtering (CFUBMS), on the fatigue behavior of Ti6Al4V ELI alloy fabricated using laser powder bed fusion (L-PBF). Post-processing techniques were analyzed for their influence on fatigue performance under diverse ambient conditions (steady and cyclic). Fatigue tests were conducted using the stress-life methodology at 25 degrees C (room temperature), 50 degrees C, 250 degrees C, -50 degrees C, and cyclic conditions ( -50/ + 50 degrees C). Structural, morphological, and mechanical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Vickers hardness testing. The microstructural analysis highlighted significant strain accumulation near fracture sites and the presence of micropores, which contributed to microcrack initiation. Results demonstrated that test temperature notably influenced fatigue life, significantly reducing under cyclic conditions ( -50/ + 50 degrees C) compared to room temperature. Heat treatment and W-DLC coating notably enhanced fatigue performance across all test conditions by forming a protective barrier and reducing residual stresses.