南京理工大学学报（自然科学版）2025，Vol.49Issue(2)：233-243,11.DOI:10.14177/j.cnki.32-1397n.2025.49.02.011
纳米层片组织纯铌的制备、组织演化与力学性能研究
Preparation,microstructure evolution and mechanical properties of pure niobium with nanolamellar structure
摘要
Abstract
The physical and chemical properties of the material can be significantly improved after the microstructure of the material is transformed into nanolamellar structure.This paper successfully prepared a pure niobium block with an average lamellar spacing of 28±8nm and a tensile strength of 1.1 GPa by a two-step deformation method of equal channel angular pressing(ECAP)followed by liquid nitrogen rolling.The study on the evolution of microstructure and mechanical properties during rolling process found that with the increase of rolling reduction ratio,the microstructure gradually changed from the near-equiaxed ultrafine grain structure after ECAP to the nanolamellar structure.As the lamellar spacing decreased to a size lower than that which inhibited the activation of the Frank-Read dislocation source,the Frank-Read dislocation source in the lamellar gradually failed.The deformation mechanism shifted from dislocation multiplication slip within the lamellar to dislocation emission at the lamellar interface,resulting in a decrease in the mean free path of dislocations,which caused a sharp decrease in the tensile plasticity of pure niobium after the rolling reduction ratio was greater than 90%.This change in deformation mechanism causes the work hardening mechanism to shift from dislocation pile-up mechanism to dislocation source activation hardening mechanism,resulting in a significant increase in the slope of the Hall-Petch relationship of nanolamellar pure niobium as the lamellar spacing is refined.关键词
剧烈塑性变形/晶粒细化/力学性能/Hall-Petch关系Key words
severe plastic deformation/grain refinement/mechanical properties/Hall-Petch relationship分类
金属材料引用本文复制引用
刘昱玮,王楷甯,蒋尧,刘瑛,王经涛..纳米层片组织纯铌的制备、组织演化与力学性能研究[J].南京理工大学学报（自然科学版）,2025,49(2):233-243,11.基金项目
国家自然科学基金(52074160 （）
52301052) （）
中央高校基本科研业务费专项资金(30923010211) （30923010211）
