Nature Communications (Feb 2024)

Amorphous alloys surpass E/10 strength limit at extreme strain rates

  • Wenqing Zhu,
  • Zhi Li,
  • Hua Shu,
  • Huajian Gao,
  • Xiaoding Wei

DOI
https://doi.org/10.1038/s41467-024-45472-z
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 8

Abstract

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Abstract Theoretical predictions of the ideal strength of materials range from E/30 to E/10 (E is Young’s modulus). However, despite intense interest over the last decade, the value of the ideal strength achievable through experiments for metals remains a mystery. This study showcases the remarkable spall strength of Cu50Zr50 amorphous alloy that exceeds the E/10 limit at strain rates greater than 107 s−1 through laser-induced shock experiments. The material exhibits a spall strength of 11.5 GPa, approximately E/6 or 1/13 of its P-wave modulus, which sets a record for the elastic limit of metals. Electron microscopy and large-scale molecular dynamics simulations reveal that the primary failure mechanism at extreme strain rates is void nucleation and growth, rather than shear-banding. The rate dependence of material strength is explained by a void kinetic model controlled by surface energy. These findings help advance our understanding on the mechanical behavior of amorphous alloys under extreme strain rates.