Enhancement of fatigue resistance by direct aging treatment in electron beam welded Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy joint

Hanqing Liu, Jun Song, Xiaojian Cao, Luopeng Xu, Yaohan Du, Lang Li, Qingyuan Wang, Qiang Chen

Research output: Contribution to journalArticlepeer-review

Abstract

In most cases, welding processes promote the application of structural materials at the expense of strength and ductility. Post-weld treatment is proposed to regain mechanical properties of weldment, which necessitates that microstructural and the associated mechanical behavior evolutions being clearly understood. In this study, post-weld heat treatment was conducted to enhance the mechanical properties of the electron beam welded Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy joint. Microstructural evolutions and monotonic mechanical properties were characterized to optimize the post-weld heat treatment parameters. It was found that direct aging at 630 °C for 2 h can upraise the strength and ductility of the joint by ∼31% and ∼511% respectively. Metastable needle-shaped martensite α′ within rapidly solidified fusion zone had been completely decomposed, and thin recrystallized α lamella precipitated in the prior β phase without forming consecutive coarse grain boundary α after above direct aging treatment. Such microstructural characteristics enable the direct-aged joint to exhibit a higher fatigue strength from high to very high cycle region than the as-welded joint. Moreover, the fatigue crack nucleation resistance was enhanced significantly through direct aged treatment.

Original languageEnglish
Article number142168
JournalMaterials Science and Engineering A
Volume829
DOIs
Publication statusPublished - Jan 1 2022

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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