Materials Research Letters (Dec 2024)

Simultaneously improving strength and ductility of laser-powder-bed-fused Al–Zn–Mg–Cu–Ti alloys by controlling phase structure of Al3Ti

  • Zhendong Jia,
  • Qiaonan Shu,
  • Biao Chen,
  • Minghao Hou,
  • Lei Jia,
  • William Yi Wang,
  • Xin Lin,
  • Pingxiang Zhang,
  • Jinshan Li

DOI
https://doi.org/10.1080/21663831.2024.2441334

Abstract

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Titanium (Ti) addition enabled the laser-powder-bed-fusion (LPBF) fabrication of 7075 (Al–Zn–Mg–Cu) alloys under the heterogeneous nucleation effect of in-situ Al3Ti phase. However, brittle D022 structured Al3Ti easily formed during LPBF, leading to unpleasant tensile properties. In this study, suppression of D022–Al3Ti was explored by adding a small amount of carbon (C) in LPBF Al–Zn–Mg–Cu–Ti alloys. It was found that C addition resulted in 118% improvement in elongation and simultaneous 23% improvement in ultimate tensile strength. The effect of C on the L12 → D022 transformation was studied by aberration-corrected transmission electron microscope and density functional theory.

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