中文摘要：

在室温，采用通道夹角为120。的变形模具对工业纯钛（Commercial Pure Titanium，CP-Ti）以Bc方式实施四道次ECAP（Equal Channel Angular Pressing）挤压变形，成功获得表面光滑无裂纹的变形试样。文中主要研究了工业纯钛在室温下进行ECAP多道次变形的组织结构演变，并测试了变形试样的力学性能。微观结构显示工业纯钛在室温下进行多道次ECAP变形时，只在前两道次产生了大量的变形孪晶，且随道次增加变形孪晶逐渐消失。最终获得的试样晶粒平均尺寸由最初的约28岬细化到约250nm，试样断裂强度和显微硬度分别提高到773和2486MPa，而试样仍保持较好的延伸率（可达16．8％）。

英文摘要：

The deformed microstructures and mechanical properties of commercial pure titanium （CP-Ti） with an initial grain size of about 28μm was investigated using equal channel angular pressing （ECAP）. ECAP was conducted at room temperature adopting a die with a channel angle of 120° via route Bc. Special attention was paid on the microstructure evolution and mechanical properties of the ECAP samples. Deformation twins were found in most grains after the first and second pass of ECAP. After four ECAP passes, the original grains were refined from 28μm to about 250 nm, and the ultimate strength and microhardness were significantly enhanced to 773 MPa and 2486 MPa, respectively. Meanwhile good ductility of 16.8% elongation still remained.