Ti-B20合金冷轧板材的再结晶行为

Recrystallization behavior of Ti-B20 alloy cold rolled sheet

对固溶态Ti-B20合金进行70%压下量的冷轧变形,然后在800℃下进行不同时间的退火处理。采用电子背散射衍射(EBSD)技术和X射线衍射(XRD)研究了Ti-B20合金冷轧板材在退火过程中的静态再结晶行为和力学性能演变。结果表明:在退火过程中,合金的再结晶晶粒优先在晶界处和变形带处形核,导致退火初期组织不均匀;随退火时间的延长,晶粒逐渐等轴化,几何必要位错(GND)密度逐渐减小并趋于稳定,抗拉强度逐渐降低,而伸长率逐渐增加;在退火30 min后,Ti-B20合金冷轧板材的抗拉强度和伸长率分别为828 MPa和23.9%。合金再结晶体积分数与退火时间之间的关系可用Johnson-Mehl-Avrami-Kolmogorov(JAMK)方程来描述(X_(800)=1-exp(-0.26×t^(0.74)))。

The solution treated Ti-B20 alloy was cold rolled with 70% reduction,and then annealed at 800℃ for different time.The static recrystallization behavior and mechanical property evolution of the Ti-B20 alloy cold rolled sheet during annealing were studied by means of electron backscatter diffraction(EBSD)technique and X-ray diffraction(XRD).The results show that during the annealing,the recrystallized grains of the alloy nucleate preferentially at the grain boundary and deformation zone,resulting in the inhomogeneous microstructure at the initial stage of annealing.With the increase of annealing time,the grains are gradually equiaxed,the density of geometrically necessary dislocations(GND)is gradually reduced and stabilized,the tensile strength is gradually reduced,and the elongation is gradually increased.After annealing for 30 min,the tensile strength and elongation of the Ti-B20 alloy cold-rolled sheet are 828 MPa and 23.9%,respectively.The relationship between the volume fraction of recrystallization of the alloy and annealing time can be described by Johnson-Mehl-Avrami-Kolmogorov(JAMK)equation:X_(800)=1-exp(-0.26×t^(0.74)).