退火温度对ECAP+CR制备的超细晶钛组织及性能影响

Effect of Annealing Temperature on Microstructure and Properties of Ultra-fine Grained Commercial Purity Titanium by ECAP+CR

工业纯钛经105°模具1道次ECAP(equal channel angular pressing,ECAP)变形与冷轧(cold rolling,CR)复合变形获得超细晶钛,通过透射电子显微镜(TEM)、单向拉伸测试及显微硬度测试等方法,研究退火温度对ECAP+CR制备的超细晶钛组织及性能的影响。结果表明:超细晶钛平均晶粒尺寸约为130 nm,抗拉强度高达813 MPa;当试样的退火温度低于400℃时,组织内部无明显变化,强度、硬度下降缓慢,延伸率提高幅度不大;退火温度高于400℃时,晶粒尺寸逐渐长大,晶粒内部位错密度降低,强度、硬度快速下降;当退火温度达到500℃时,晶粒急剧长大,平均晶粒尺寸约为2μm。

Ultra-fine grained commercial purity（CP） Titanium was processed by equal channel angular pressing（ECAP） at room temperature and ECAP followed by cold rolling（CR）. Effect of annealing temperature on microstructure and properties of ultra-fine grained commercial purity Ti were investigated by transmission electron microscopy（TEM）,uniaxial tensile test and microhardness test. The results show that the average size of ultra-fine grain is about 130 nm,and ultimate tensile strength is 813 MPa. When the annealing temperature is below 400 °C,the microstructure has no obvious change. Ultimate tensile strength and microhardness slightly decrease. At the same time,elongation increases. When the annealing temperature is higher than 400 °C,grain size of ultra-fine grained CP Ti grows slowly,and dislocation density decreases; besides,ultimate tensile strength and microhardness decreases obviously. When the annealing temperature is 500 °C,grain size of ultra-fine grained CP Ti grows rapidly,and the average grain size is ~2 μm.