Zhu Wenqing, Li Zhi, Shu Hua, Gao Huajian, Wei Xiaoding
State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, 100871, China.
Institute of High Performance Computing, Agency for Science, Technology and Research (A*STAR), Singapore, 138632, Republic of Singapore.
Nat Commun. 2024 Feb 26;15(1):1717. doi: 10.1038/s41467-024-45472-z.
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 CuZr amorphous alloy that exceeds the E/10 limit at strain rates greater than 10 s 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.
材料理想强度的理论预测值在E/30至E/10之间（E为杨氏模量）。然而，尽管在过去十年中人们对此兴趣浓厚，但通过实验获得的金属理想强度值仍是个谜。本研究通过激光诱导冲击实验展示了CuZr非晶合金卓越的层裂强度，该强度在应变速率大于10 s时超过了E/10的极限。这种材料的层裂强度为11.5 GPa，约为E/6或其纵波模量的1/13，这创造了金属弹性极限的记录。电子显微镜和大规模分子动力学模拟表明，在极端应变速率下的主要失效机制是空穴形核与生长，而非剪切带。材料强度的速率依赖性由表面能控制的空穴动力学模型来解释。这些发现有助于推进我们对非晶合金在极端应变速率下力学行为的理解。
