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选取热轧退火态的工业纯钛(CP-Ti)板材为研究对象,采用通道夹角Φ=135°的模具,在室温下进行CP-Ti板状试样1~8道次等径弯曲通道变形(ECAP),利用金相显微镜(OM)和透射电镜(TEM)观察并分析了纯钛板材在不同道次变形后的组织演变过程。通过力学性能测试实验,分析了X,Y,Z面硬度的变化过程,研究了ECAP变形对CP-Ti力学性能的影响规律。结果表明:CP-Ti板材经过ECAP变形,晶粒逐渐拉长,组织位错大量增加,出现板条状组织;8道次ECAP变形后CP-Ti板材的晶粒明显细化,晶粒尺寸由原始的57.000μm细化到0.668μm;随着挤压道次的增加,组织位错逐渐消失,小角度晶界逐渐转变为大角度晶界,晶粒越来越细,最终达到纳米级别。CP-Ti板材1道次ECAP变形后硬度变化程度最大,X,Y,Z面的硬度增幅分别达32.6%,33.8%和32.9%;随着道次增加,8道次ECAP变形后,力学性能显著提高,X,Y,Z面的硬度最终达到1910,1943和1911 MPa。
The hot rolled and annealed industrial pure titanium (CP-Ti) sheet was chosen as the research object. The CP-Ti plate sample was tested at room temperature for 1 ~ 8 times of equal diameter curved channel (ECAP). The microstructure evolution of pure titanium plate after different passes was observed and analyzed by OM and TEM. The change of hardness of X, Y and Z surfaces was analyzed through mechanical properties test. The influence of ECAP deformation on the mechanical properties of CP-Ti was studied. The results show that the CP-Ti sheet undergoes ECAP deformation, the grains are gradually elongated, and the dislocation of the structure increases a lot, and the lath-like structure appears. The grains of the CP-Ti sheet are refined obviously after ECAP deformation of 8 passes, The original 57.000μm thinned to 0.668μm. With the increase of extrusion pass, the dislocations gradually disappeared, the small-angle grain boundaries gradually transformed into large-angle grain boundaries, and the grains became finer and finer, finally reaching nanometer level. The hardness changes of the CPAP-Ti sheet after ECAP deformation are the largest, and the hardness increases by 32.6%, 33.8% and 32.9% after ECAP deformation respectively. With the increase of pass, the mechanical properties The hardness of X, Y and Z surfaces finally reached 1910, 1943 and 1911 MPa.