Xu Sheng, Odaira Takumi, Sato Shunsuke, Xu Xiao, Omori Toshihiro, Harjo Stefanus, Kawasaki Takuro, Seiner Hanuš, Zoubková Kristýna, Murakami Yasukazu, Kainuma Ryosuke
Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba-yama, Sendai, 980-8579, Japan.
J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan.
Nat Commun. 2022 Sep 27;13(1):5307. doi: 10.1038/s41467-022-32930-9.
Crystalline metals can have large theoretical elastic strain limits. However, a macroscopic block of conventional crystalline metals practically suffers a very limited elastic deformation of <0.5% with a linear stress-strain relationship obeying Hooke's law. Here, we report on the experimental observation of a large tensile elastic deformation with an elastic strain of >4.3% in a Cu-based single crystalline alloy at its bulk scale at room temperature. The large macroscopic elastic strain that originates from the reversible lattice strain of a single phase is demonstrated by in situ microstructure and neutron diffraction observations. Furthermore, the elastic reversible deformation, which is nonhysteretic and quasilinear, is associated with a pronounced elastic softening phenomenon. The increase in the stress gives rise to a reduced Young's modulus, unlike the traditional Hooke's law behaviour. The experimental discovery of a non-Hookean large elastic deformation offers the potential for the development of bulk crystalline metals as high-performance mechanical springs or for new applications via "elastic strain engineering."
晶体金属可具有较大的理论弹性应变极限。然而，传统晶体金属的宏观块体实际上仅承受非常有限的弹性变形，即小于0.5%，其应力-应变关系呈线性，遵循胡克定律。在此，我们报告了在室温下对一种铜基单晶合金在体尺度上进行的实验观察，该合金表现出大于4.3%的弹性应变的大拉伸弹性变形。通过原位微观结构和中子衍射观察证实，这种大的宏观弹性应变源自单相的可逆晶格应变。此外，这种弹性可逆变形是非滞后且准线性的，与明显的弹性软化现象相关。与传统胡克定律行为不同，应力增加会导致杨氏模量降低。非胡克型大弹性变形的实验发现为开发作为高性能机械弹簧的块状晶体金属或通过“弹性应变工程”实现新应用提供了潜力。
