Amorphous alloys surpass E/10 strength limit at extreme strain rates.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38403631.
- Also identified by DOI 10.1038/s41467-024-45472-z and PMC identifier 10894860.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 Cu<sub>50</sub>Zr<sub>50</sub> amorphous alloy that exceeds the E/10 limit at strain rates greater than 10<sup>7</sup> s<sup>-1</sup> 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.