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为实现钛合金初生带状α相的球化,以具有这种组织的TA15钛合金为对象,研究其在热加工中的组织演变。结果表明:带状α相形态演变的机理与片层组织球化机理相同。由于带状α相尺寸较大,界面分离和末端物质迁移机制较粗化更为重要。带状α相在退火中较为稳定,主要原因是:内部晶界的几何取向不利于球化、带状组织的宽度较大和α粒子几何稳定性高。预变形和低速变形通过以下方式加速球化:直接改变α相的几何形状、通过增加大角度晶界以及相界的面积促进界面分离和末端物质迁移、通过形成位错结构促进粗化。采用大预变形结合高温退火是球化带状α相的有效途径。
In order to realize the spheroidization of primary ribbon α phase of titanium alloy, TA15 titanium alloy with this kind of structure was taken as the object to study its microstructure evolution during hot working. The results show that the mechanism of ribbon α morphology evolution is the same as that of lamellar organization. Due to the larger size of the ribbon α phase, it is more important to separate the interfaces and coarser the terminal material migration mechanism. The main reason that the ribbon α phase is relatively stable during annealing is that the geometric orientation of the internal grain boundaries is not conducive to spheroidization, the width of the ribbon structure is large and the α-particle geometry stability is high. Pre-deformation and low-speed deformation accelerate spheroidization by directly changing the geometry of the alpha phase, promoting interfacial separation and terminal material migration by increasing the large-angle grain boundaries and phase boundary areas, and promoting coarsening by forming dislocation structures. The use of large pre-deformation combined with high-temperature annealing is an effective way to spheroidized α-phase.