纳米晶纯钛电流辅助微成形尺度效应及增塑机制研究

In this proposal, electrical-assisted microforming method is proposed aiming at micro-fabrication of mini-implants in nanocrystalline pure titanium. Micro/nano mechanical properties testing device will be developed under multi-field coupling of electro-thermo-mechanical. Micro-deformation behavior and micro-friction will be investigated during electrical-assisted microforming in nanocrystalline pure titanium. Ductilization induced by interaction of nanocrystalline material and electric pulse will be discussed during micro-deformation in nanocrystalline pure titanium. Effect of interface contact between the surface nanostructures and micro-mould constraint will be analyzed. By considering the interplay of surface layer/interface effect, electroplastic and Joule heating effects, a theoretical model for multi-field coupling size will be established to explain the size effect mechanism of electrical-assisted microforming. In addition, microstructural evolution under multi-field coupling effect will be studied and the thermodynamic and kinetic problems will be discussed in nanocrystalline pure titanium to reveal the thermostability mechanism during electrical-assisted microforming in nanocrystalline pure titanium under multi-field coupling effect. Based on these results, electral-assisted microforming processes of mini-implants will be conducted with nanocrystalline pure titanium and mini-dental-implants will be fabricated with high dimensional accuracy and mechanical properties. The developments of this project are playing important roles of scientific significants in promoting the microforming technology for protential application values in biological and medical fields.

本项目针对纳米晶纯钛微型植入体微制造问题，提出了电流辅助微成形工艺方法，研制了电-热-力多场耦合作用下微纳米力学性能测试装置，研究纳米晶纯钛电流辅助微塑性变形行为和微摩擦行为，探讨纳米晶材料与脉冲电流在微成形过程的增塑机制，分析材料表面纳米结构与微模具约束的界面接触效应，考虑表面层/界面效应、电致塑性效应及焦耳热效应的相互作用，建立纳米晶纯钛微成形多场耦合效应理论模型，揭示纳米晶纯钛电流辅助微成形尺度效应机理。进一步研究多场耦合作用下纳米晶纯钛微观组织演变规律，探讨纳米晶纯钛微塑性变形的热力学和动力学问题，揭示纳米晶纯钛电流辅助微成形热稳定性机理。在此基础上，研究纳米晶纯钛电流辅助微成形工艺，实现微型牙科植入体的高精度和高性能可控制造。项目的开展对于促进塑性微成形技术在生物医疗领域的实际应用具有重要的科学意义和应用价值。

本项目针对纳米晶纯钛微型植入体微制造技术问题，提出了脉冲电流辅助微成形新方法，研制了一台电流辅助微尺度力学性能测试装置，系统研究了纳米晶纯钛电流辅助微塑性变形行为，建立了纳米晶纯钛电流辅助微成形数学本构模型，揭示了纳米晶纯钛电流辅助微成形增塑机制。进一步研究了脉冲电流辅助微成形过程微观组织结构演化规律，提出了基于晶界局部焦耳热效应的微成形尺度效应理论模型，揭示了纳米晶纯钛电流辅助微成形电致塑性效应机理。在此基础上，设计了一套基于脉冲电流辅助微成形模具装置，实现了纳米晶纯钛微型植入体高质量成形。共发表学术SCI收录10篇，包括塑性成形领域TOP1期刊IJP论文1篇。撰写英文专著1章，申请国家发明专利4项，已授权1项，作国际会议特邀报告6次，培养研究生9人。本项目的实施为纳米结构材料在微成形技术的应用提供了重要理论支撑。