Theory-guided materials design of multiphase alloys with superior stiffness at finite temperatures

Jinhui Huang, Shuhong Liu, Martin Friák, Chengliang Qiu, Shun Li Shang, Zi Kui Liu, Yong Du

Research output: Contribution to journalArticlepeer-review

Abstract

Aiming at designing Mg alloys with a significantly increased stiffness at elevated temperatures, we propose a high-precision multi-scale methodology to compute temperature-dependent elastic modulus of homogeneous multiphase alloys. The proposed method combines (i) first-principles calculations of temperature- and solid solubility-dependent elastic properties in individual phases with (ii) a two-level multiphase homogenization at the continuum level and (iii) a phenomenological thermodynamic modeling by the CALPHAD approach. According to the post-average approximation during the calculation, the stresses and strains of individual phases in the alloy are superimposed before undergoing the average approximation. This is different from the traditional method which consider forces as acting axially assumptions of isostrain and isostress model and followed by numerical averaging. We applied the proposed method in light-weight Mg-alloys, in particular, a three-phase alloy with the composition Mg0.878Al0.083Si0.039, and verified it through experimental measurements. The present work identifies that MgxAlySi1-x-y with 0 ≤ x ≤ 0.87 and 0 ≤ y ≤ 0.87-x are candidate compositions with Young's modulus exceeding 60 GPa at 623 K.

Original languageEnglish (US)
Article number119796
JournalActa Materialia
Volume269
DOIs
StatePublished - May 1 2024

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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