TC17钛合金热变形过程中片状组织演变规律

Research on the Microstructure Evolution of TC17 Titanium Alloy during Hot Deformation

通过等温锻造试验和有限元模拟,研究了TC17钛合金在α+β两相区变形过程中热加工工艺参数对显微组织演变的影响规律。通过组织观察分析发现:随着变形程度和变形温度的增加,TC17钛合金中的片层组织逐渐向球化组织转变。变形量对片状组织的球化起决定作用,当变形量为小于20%时,仅有少数片状α相发生了弯折或扭曲,球化现象不明显;随着变形量的增加,片状组织被不同程度的弯曲、破碎,球化程度随着变形量的增加逐渐变大。变形温度对球化过程也起一定的作用,随着变形温度的升高,球化效果越来越明显,这与较高的变形温度会提高位错或原子的迁移能力使片状组织有足够的能量通过界面迁移实现断裂、球化有关。

The effects of the hot -working parameters on the microstructure of TC17 titanium alloy in the two phases have been investigated by the isothermal forging test and combined with finite element simulation. The results show that with the increasing strain and temperature, the lamellar αchange into globular αgradually. Deformation is crucial in the globularization process. At the deformation less than 20% only a few lamellar α are kinked or buckled and the globularization process is conducted incompletely. With the increasing strain, the lamellar α are broken -up and change into globular α, and the globularization process conducted completely. The deformation temperature also plays an important role in the globularization process and with the increasing temperature the globularization process be- come obviously. It indicates that the high deformation temperature can improve the migration ability of dislocation or atomic, then the interface can migrate to achieving the dynamic globularization of the lamellae.