退火温度对纯钛TA1织构及各向异性的影响

Effect of annealing temperature on texture and anisotropy of mechanical properties of pure titanium(TA1) sheet

通过X线衍射(XRD)和电子背散射衍射(EBSD)等分析技术,研究退火温度对冷轧态TA1钛板显微组织及织构的影响规律。研究结果表明:TA1钛板冷轧退火后,微观组织发生再结晶并形成典型的双峰分裂基面织构特征。在退火温度不大于700℃时,组织变化主要以回复与再结晶的形核生长为主,生成■和■类型再结晶织构组分,此时轧制织构组分逐渐消失;当退火温度达到800℃时,晶粒变化以合并长大为主,再结晶织构组分■的强度也继续增强。同时,织构组分对板材的各向异性有着直接影响,由于棱锥型织构■再结晶织构组分特征的作用,可开动的滑移系统分别为易激活的柱面<a>滑移和较难开动的基面<a>滑移或棱锥面<c+a>滑移,从而导致板面内TD方向的拉伸强度比RD方向的拉伸强度大,而45°方向强度最低,从而产生较大的板面各向异性。

The effect of evolution of microstructure and texture of commercially pure titanium (TA1) annealed at different temperatures was investigated by X-ray diffraction (XRD), and electron backscattered diffraction (EBSD). The results show that recovery and recrystallization of the cold rolled TA1 titanium sheet occur during the annealing process, and typical TD-split basal texture was formed. When the annealing temperature is below 700 ℃, the microstructure is characterized by recovery and recrystallization, and recrystallization texture components are presented. The as-rolled texture component is gradually weakened and disappears with the increase of the heat treatment temperature. When the annealing temperature reaches 800 ℃, the grain growth is dominated by merged-growth and the intensity of (0113)<2130> and (1122)<1100 > recrystallized texture component continue to increase. In addition, anisotropy of mechanical properties of TA1 sheet is related to the texture components. Due to pyramid textures (0113)<2130> and (1122)<1100 > recrystallization textures, the cylinder <a> slip is respectively easier to be activated and the base <a> slip or pyramidal plane <c+a> slip becomes more difficult to be activated respectively, which leads to greater tensile strength in the TD direction than the RD direction of the sheet. As a result, the anisotropy of mechanical properties of TA1 sheet is caused.