Ti6Al4V钛合金的变形组织及织构

摘要

在温度850~930°C、应变速率0.01~1 s-1的条件下，对初始组织为等轴组织的Ti6Al4V钛合金进行变形程度为70%的热压缩变形实验，研究合金的变形组织及织构。结果表明，当温度低于900°C、应变速率高于0.1 s-1时，合金的组织主要是拉长的α晶粒；而在高于900°C以及低应变速率下，则会发生动态再结晶。电子背散射衍射(EBSD)结果显示，合金在再结晶过程中亚晶界吸收位错，最终形成大角晶界。在930°C时动态再结晶已基本完成，水冷至室温时形成针状α相。与原始组织相比，合金在930°C变形时织构得到增强，低于930°C变形时织构变弱。%Microstructure and texture evolution during hot compression of Ti6Al4V alloy with an initial equiaxed microstructure were studied in the temperature range of 850-930 °C, strain rate range of 0.01-1 s-1 and engineering compressive strain of 70%. The results indicate that when temperature is below 900 °C and strain rate is higher than 0.1 s-1, the microstructure is mainly composed of elongatedα grains. While deforming at higher temperatures and lower strain rates, dynamic recrystallization takes place. Electron back scattered diffraction (EBSD) result shows that during dynamic recrystallization, subgrain boundaries absorb dislocations and the recrystallized grains with high angle grain boundary form. At 930 °C dynamic recrystallization has basically completed, and needlelikeα phase forms after water quenching. Pole figure analysis indicates that compared with the initial specimen, textures below 930 °C are weaker, while at 930 °C they are stronger.