Microstructure and deformation behavior of Ti-6Al-4V alloy by high-power laser solid forming

Y. M. Ren, X. Lin, X. Fu, H. Tan, J. Chen, W. D. Huang

Research output: Contribution to journalArticlepeer-review

278 Scopus citations

Abstract

This work investigated the microstructure and tensile deformation behavior of Ti-6Al-4V alloy fabricated using a high-power laser solid forming (LSF) additive manufacturing. The results show that the post-fabricated heat-treated microstructure consists of coarse columnar prior-β grains (630–1000 μm wide) and α-laths (5–9 μm) under different scanning velocities (900 and 1500 mm/min), which caused large elongation (∼18%) superior to the conventional laser additive manufacturing Ti-6Al-4V alloy. The deformation behavior of the LSF Ti-6Al-4V alloy was investigated using in situ tensile test scanning electron microscopy. The results show that shear-bands appeared along the α/β interface and slip-bands occurred within the α-laths, which lead to cracks decaying in a zigzag-pattern in the LSF Ti-6Al-4V alloy with basket-weave microstructure. These results demonstrate that the small columnar prior-β grains and fine basket-weave microstructure exhibiting more α/β interfaces and α-laths can disperse the load and resist the deformation in the LSF Ti-6Al-4V components. In addition, a modified microstructure selection map of the LSF Ti-6Al-4V alloy was established, which can reasonably predict the microstructure evolution and relative grain size in the LSF process.

Original languageEnglish
Pages (from-to)82-95
Number of pages14
JournalActa Materialia
Volume132
DOIs
StatePublished - 15 Jun 2017

Keywords

  • Additive manufacturing
  • Deformation behavior
  • In situ tensile
  • Laser solid forming
  • Ti-6Al-4V

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