退火对复合变形超细晶TA1纯钛组织性能的影响  

Effect of annealing on microstructure and properties of composite deformed ultrafine grained TA1 pure titanium

作　　者：甘晨 罗雷[1] 杨西荣[1] 刘晓燕[1] 杨博海 闫文文 GAN Chen;LUO Lei;YANG Xi-rong;LIU Xiao-yan;YANG Bo-hai;YAN Wen-wen(College of Metallurgical Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710055

出　　处：《材料热处理学报》2025年第2期106-113,共8页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51474170);陕西省自然科学基金面上项目(2020JM-493);西安建筑科技大学国基金培育专项(X20240094)。

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。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.

关 键 词：超细晶工业纯钛 等通道转角挤压+旋锻 退火温度 微观组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]