发表机构
Czech Technical University in Prague; FZU - Institute of Physics of Czech Academy of Sciences; Faculty of Mechanical Engineering, Czech Technical University in Prague; University of Chemistry and Technology（布拉格捷克理工大学; 捷克科学院物理研究所; 布拉格捷克理工大学机械工程学院; 化学技术大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过直接挤压制备了纯锌及Zn-Mg、Zn-Mg-Sr细线，发现合金化显著细化晶粒并提升强度，但所有线材循环弯曲性能差，归因于孪晶-去孪晶机制，阻碍了弯曲关键型生物医学应用。
AI 中文摘要
锌基合金是有前景的可生物降解植入材料，然而在细线形态下强度、延展性和弯曲性之间的权衡仍知之甚少。为解决这一问题，通过直接挤压制备了直径约290微米的纯锌（PZ）、Zn-0.15Mg（ZM）和Zn-0.8Mg-0.2Sr（ZMS）线材，并表征了其微观结构、织构、拉伸和弯曲行为。Mg2Zn11和SrZn13相促进了粒子刺激形核，将晶粒尺寸从PZ中的35.8微米细化至ZM和ZMS中的6.8和3.3微米，削弱了基面纤维织构，并在37°C下将极限抗拉强度从PZ的约119 MPa分别提高至ZM和ZMS的291和334 MPa。PZ通过弱取向差晶粒间的孪晶传递发生变形，在拉伸曲线中产生锯齿状应力下降，进一步的应变由非基面滑移容纳。ZM表现出单一的、对时效敏感的应力下降，源于局部孪晶形核和颗粒开裂，而ZMS表现出分布式的颗粒开裂而无相关应力下降，与其在37°C下19%的较高断裂伸长率一致。在37°C下时效20天后，力学性能大体保持稳定，7天后纳米级析出物无可测量变化。然而，所有成分均表现出显著较差的循环弯曲性能，并伴随首次在锌中通过EBSD直接观察到的孪晶-去孪晶机制。这些结果表明，单步直接挤压是制备高强度、细晶粒可生物降解锌线材的可行途径，同时确定较差的弯曲性是弯曲关键型生物医学器件的主要障碍。
英文摘要
Zinc-based alloys are promising biodegradable implants, yet the trade-off between strength, ductility, and bendability in thin-wire form remains poorly understood. To address this, pure Zn (PZ), Zn-0.15Mg (ZM), and Zn-0.8Mg-0.2Sr (ZMS) wires of ~290 um diameter were produced by direct extrusion, and their microstructure, texture, tensile, and bending behavior were characterized. Mg2Zn11 and SrZn13 phases promoted particle-stimulated nucleation, refining the grain size from 35.8 um in PZ to 6.8 and 3.3 um in ZM and ZMS, respectively, weakening the basal-fiber texture, and raising the ultimate tensile strength at 37 °C from about 119 MPa for PZ to 291 and 334 MPa for ZM and ZMS, respectively. PZ deformed through twin transmission across weakly misoriented grains, producing serrated stress drops in tensile curves, with further straining accommodated by non-basal slip. ZM showed a single, aging-sensitive stress drop from localized twin nucleation and particle cracking, while ZMS showed distributed particle cracking without associated stress drops, consistent with its higher elongation to failure of 19 % at 37 °C. Mechanical properties remained broadly stable after 20 days of aging at 37 °C, with no measurable change in the nanoscale precipitates after 7 days. All compositions, however, showed markedly poor cyclic bendability accompanied by a twinning-detwinning mechanism directly observed by EBSD for the first time in zinc. These results establish single-step direct extrusion as a viable route to strong, fine-grained biodegradable Zn wires, while identifying poor bendability as the principal obstacle to bending-critical biomedical devices.
