【摘要】 采用四道次等通道转角挤压(Equal channel angular pressing, ECAP)和旋锻(Rotary swaging, RS)复合变形工艺将TA1纯钛(CP-Ti)制备成超细晶工业纯钛(UFG CP-Ti),研究了不同退火温度(200～500℃)对UFG CP-Ti显微组织及力学性能的影响。结果表明：经ECAP+RS工艺处理后，CP-Ti的晶粒尺寸明显细化，平均晶粒尺寸从28μm细化至180 nm,抗拉强度和屈服强度显著增加，分别从255和310 MPa提高到816和835 MPa,但伸长率从20%降低到15%。在200～350℃退火时，UFG CP-Ti的位错密度降低，显微硬度缓慢下降，晶粒发生回复过程。在400℃退火时，发生了再结晶和晶粒长大，退火温度升高到500℃时，晶粒长大至2μm,显微硬度显著下降。经350℃退火后，UFG CP-Ti的力学性能较好，其屈服强度、抗拉强度和伸长率分别为604 MPa、618 MPa和24%,拉伸试样的断口存在大量的韧窝，韧窝的平均直径小于2μm,表现出典型的韧性断裂特征。更多还原

【Abstract】 TA1 pure titanium(CP-Ti) was prepared into ultrafine grained industrial pure titanium(UFG CP-Ti) using a composite deformation process of four passes of equal channel angular pressing(ECAP) and rotary swaging(RS). The effect of different annealing temperatures(200-500 ℃) on microstructure and mechanical properties of the UFG CP-Ti was studied. The results show that after ECAP+RS process treatment, the grain size of the CP-Ti is significantly refined with the average grain size decreasing from 28 μm to 180 nm, the tensile strength and yield strength significantly increase, from 255 and 310 MPa to 816 and 835 MPa, respectively, but the elongation decreases from 20% to 15%. When annealed at 200-350 ℃, the dislocation density of the UFG CP-Ti decreases, the microhardness slowly decreases, and the grains undergo a recovery process. When annealed at 400 ℃, the recrystallization and grain growth occur. When the annealing temperature increases to 500 ℃, the grains grow to 2 μm and the microhardness significantly decreases. After annealing at 350 ℃, the mechanical properties of the UFG CP-Ti are good, with yield strength, tensile strength, and elongation of 604 MPa, 618 MPa, and 24%, respectively. The fracture surface of the tensile specimen contains a large number of ductile dimples, with an average diameter of less than 2 μm, exhibiting typical ductile fracture characteristics.更多还原