中文摘要：

采用等径弯曲通道变形（Equal Channel Angular Pressing,ECAP）技术制备了不同晶粒尺寸的超细晶工业纯钛,通过纳米压痕测试技术对ECAP变形工业纯钛的力学性能进行研究,讨论了加载应变速率和晶粒尺寸对工业纯钛硬度测试结果的影响,进一步分析了ECAP变形工业纯钛的应变硬化能力和残余应力。结果表明：随着加载应变速率的增大和晶粒尺寸的减小,工业纯钛的硬度值增加。硬度-位移曲线表现出具有硬化效应的压痕尺寸效应（Indentation Size Effect,ISE）。纳米压痕形貌表明：ECAP变形工业纯钛的应变硬化能力降低,存在残余压应力。

英文摘要：

Ultrafine grained commercially pure Ti with different grain sizes was prepared by Equal Channel Angular Pressing（ECAP）. The mechanical properties of the commercially pure Ti were investigated by a nanoindentation technique. The effects of loading strain rate and grain size on the nanoindentation measurement of commercially pure Ti were discussed. Strain hardening capacity and residual stress of commercially pure Ti were analyzed. The results indicate that the hardness of commercially pure Ti increases with the loading strain rate increasing and the grain size decreasing. The hardness-dislocation curves exhibit the Indentation Size Effect（ISE） with the incorporated hardening effect. The indentation morphology shows that commercially pure Ti processed by ECAP has low strain hardening capacity and compressive residual stress compared to the coarse-grained sample.