Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, and State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an, China.
School of Materials Science and Engineering, Sichuan University, Chengdu, China.
Nature. 2024 Sep;633(8030):575-581. doi: 10.1038/s41586-024-07900-4. Epub 2024 Sep 4.
Futuristic technologies such as morphing aircrafts and super-strong artificial muscles depend on metal alloys being as strong as ultrahigh-strength steel yet as flexible as a polymer. However, achieving such 'strong yet flexible' alloys has proven challenging because of the inevitable trade-off between strength and flexibility. Here we report a Ti-50.8 at.% Ni strain glass alloy showing a combination of ultrahigh yield strength of σ ≈ 1.8 GPa and polymer-like ultralow elastic modulus of E ≈ 10.5 GPa, together with super-large rubber-like elastic strain of approximately 8%. As a result, it possesses a high flexibility figure of merit of σ/E ≈ 0.17 compared with existing structural materials. In addition, it can maintain such properties over a wide temperature range of -80 °C to +80 °C and demonstrates excellent fatigue resistance at high strain. The alloy was fabricated by a simple three-step thermomechanical treatment that is scalable to industrial lines, which leads not only to ultrahigh strength because of deformation strengthening, but also to ultralow modulus by the formation of a unique 'dual-seed strain glass' microstructure, composed of a strain glass matrix embedded with a small number of aligned R and B19' martensite 'seeds'. In situ X-ray diffractometry shows that the polymer-like deformation behaviour of the alloy originates from a nucleation-free reversible transition between strain glass and R and B19' martensite during loading and unloading. This exotic alloy with the potential for mass producibility may open a new horizon for many futuristic technologies, such as morphing aerospace vehicles, superman-type artificial muscles and artificial organs.
未来主义技术，如变形飞机和超强人工肌肉，都依赖于金属合金，这些合金既要像超高强度钢一样坚固，又要像聚合物一样灵活。然而，由于强度和灵活性之间不可避免的权衡，实现这种“强而灵活”的合金一直具有挑战性。在这里，我们报告了一种 Ti-50.8at.%Ni 应变玻璃合金，它具有超高屈服强度 σ≈1.8GPa 和聚合物般超低弹性模量 E≈10.5GPa，以及约 8%的超大大橡胶状弹性应变。因此，它具有高灵活性的衡量标准 σ/E≈0.17，与现有结构材料相比。此外，它可以在-80°C 至+80°C 的宽温度范围内保持这种性能，并在高应变下表现出优异的耐疲劳性。该合金通过简单的三步热机械处理制造，该处理可扩展到工业生产线，这不仅导致了超高强度，因为变形强化，而且通过形成独特的“双种子应变玻璃”微观结构，也导致了超低模量，该微观结构由应变玻璃基质嵌入少量对齐的 R 和 B19'马氏体“种子”组成。原位 X 射线衍射表明，该合金的聚合物状变形行为源于在加载和卸载过程中应变玻璃和 R 和 B19'马氏体之间无核可逆转变。这种具有大规模生产潜力的奇特合金可能为许多未来主义技术开辟新的前景，例如变形航空航天飞行器、超人型人工肌肉和人工器官。
