Novel high-strength Al-Cu-Cd alloy fabricated by arc-directed energy deposition: Precipitation behavior of the Cd phase and grain evolution

Zhennan Wang, Xin Lin, Lilin Wang, Haiou Yang, Yinghui Zhou, Julia Kristin Hufenbach, Konrad Kosiba, Tianchi Zhang, Weidong Huang

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

In this study, a simple and efficient method for obtaining high strength and ductility, i.e., microalloying with Cd, was used for the Al-Cu alloy fabricated by the arc-directed energy deposition (Arc-DED). The resulting deposits exhibited fully equiaxed grain characteristics, and the higher growth restriction factor caused by the higher content of Ti and large nucleation density of Al3Ti precipitates led to the formation of fully α-Al equiaxed grains during solidification, unlike other Arc-DED-deposited Al alloys. A relationship between the number of Al3Ti nuclei and the cooling rate during the Arc-DED process was established. Furthermore, the orientation relationship between the Cd phase and α-Al matrix was defined. The Arc-DED-fabricated material was T6 heat-treated (solution + artificial aging). In the aging stage, the metastable nanoscale Cd particles precipitated with a spherical shape (2 nm in diameter) into a face-centered cubic structure with lattice parameters similar to the α-Al matrix, as suggested by the in-depth transmission electron microscopic analysis. The T6-treated Arc-DED-deposited Al-Cu-Cd alloy shows a superior balance of strength and ductility (yield strength of 414.0 MPa, ultimate tensile strength of 475.8 MPa, and elongation to failure of 11.9%) and outperforms other additively manufactured Al-Cu-based materials. This superior tensile mechanical performance is attributed to its finely distributed and equiaxed grains, and the high density of the strengthening θ′-Al2Cu phase.

Original languageEnglish
Article number103278
JournalAdditive Manufacturing
Volume60
DOIs
StatePublished - Dec 2022

Keywords

  • Al-Cu-Cd alloy
  • Arc-directed energy deposition
  • Cadmium precipitation behavior
  • High strength and ductility
  • Microstructure formation mechanism

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