西安交通大学任晓兵研究团队取得一项新突破。他们开发出一种类似聚合物的超高强度金属合金。2024年9月4日出版的《自然》发表了这项成果。

据悉，未来的技术，如变形飞机和超强人造肌肉，都依赖于金属合金，它们既要像超高强度的钢一样坚固，又要像聚合物一样柔韧。然而，实现这种“强而柔韧”的合金已被证明具有挑战性，因为强度和柔韧之间不可避免的权衡。

在该研究中，课题组研究人员报道了一种Ti-50.8 at.% Ni的应力玻璃合金，具有超高屈服强度σ_y ≈1.8 GPa和类聚合物的超低弹性模量E ≈ 10.5 GPa，加上超大的约8%橡胶样弹性应变。因此，与现有结构材料相比，它具有较高的柔性系数σ_y/E ≈ 0.17。此外，它可以在零下80°C至+80°C的宽温度范围内保持这些性能，在高应力下表现出优异的抗疲劳的性能。

该合金是通过简单的三步热机械处理制成的，可扩展到工业流水线，不仅由于变形强化而具有超高强度，而且通过形成独特的“双种子应变玻璃”微观结构而具有超低模量，该微观结构由应变玻璃基体嵌入少量排列的R和B19'马氏体种子组成。

原位X射线衍射分析表明，合金的类聚合物变形行为源于加载和卸载过程中，应变玻璃与R和B19′马氏体之间的无核可逆转变。这种具有大规模生产潜力的奇异合金可能为许多未来技术开辟新的领域，如变形航天飞行器、超人型人造肌肉和人造器官。

附：英文原文

Title: A polymer-like ultrahigh-strength metal alloy

Author: Xu, Zhizhi, Ji, Yuanchao, Liu, Chang, He, Liqiang, Zhao, Hui, Yuan, Ye, Qian, Yu, Cui, Jin, Xiao, Andong, Wang, Wenjia, Yang, Yang, Ma, Tianyu, Ren, Xiaobing

Issue&Volume: 2024-09-04

Abstract: 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–50.8at.% Ni strain glass alloy showing a combination of ultrahigh yield strength of σy≈1.8GPa and polymer-like ultralow elastic modulus of E≈10.5GPa, together with super-large rubber-like elastic strain of approximately8%. As a result, it possesses a high flexibility figure of merit of σy/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.

DOI: 10.1038/s41586-024-07900-4

Source: https://www.nature.com/articles/s41586-024-07900-4