Microstructure evolution and static recrystallization during hot rolling and annealing of an equiaxed-structure TC21 titanium alloy
Microstructure evolution and static recrystallization during hot rolling and annealing of an equiaxed-structure TC21 titanium alloy
复制标题
等轴组织TC21钛合金热轧和退火过程中的显微组织演变和静态再结晶
DOI：
10.1016/j.jallcom.2018.04.148
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发表时间：
2018-07-05
影响因子：
6.2
通讯作者：
Liu, Qing
中科院分区：
文献类型：
--
作者：
Wang, Ke;Wu, Mingyu;Liu, Qing
将由主要等轴α晶粒和剩余β相组成的等轴结构TC21钛合金在750 ℃下热轧，随后在不同温度下退火。利用电子背散射衍射（EBSD）技术研究了该合金在轧制和退火过程中的微观组织演变和静态再结晶（SRX）。在轧制和退火过程中，晶粒形貌发生了明显的演变。在热轧过程中，等轴α晶粒沿横向（TD）沿着被拉长，退火过程中由于SRX和晶界分裂而获得等轴形貌。相反，随后的退火对织构的影响有限。核平均取向差（KAM）计算表明，β相比α相承受更大的变形量，这导致β相更优先的SRX。同时，α相和β相的不同SRX机制导致了SRX和晶粒形貌随退火温度的不同演化。随着退火温度的升高，α相的连续SRX（cSRX）使SRX分数增加，晶粒尺寸减小，但在940 ℃时晶粒长大。而SRX则通过亚晶合并发生在β相中，随着退火温度的升高，晶粒尺寸增大，SRX分数降低。因此，880 ℃是获得均匀和细化的组织的热轧TC21钛合金的合适退火温度。(C)2018 Elsevier B.V.版权所有。
An equiaxed-structure TC21 titanium alloy, consisting of predominant equiaxed alpha grains and remained beta phase, was hot rolled at 750 degrees C, and subsequently annealed at different temperatures. Based on electron back-scattered diffraction (EBSD) observation, the microstructure evolution and static recrystallization (SRX) during rolling and annealing were investigated. An apparent evolution of grain morphology occurred during rolling and annealing. The equiaxed a grain was elongated along the transverse direction (TD) during hot rolling, and then got an equiaxed morphology due to the SRX and boundary splitting during annealing. In contrast, subsequent annealing had a limited effect on the textures. The Kernel Average Misorientation (KAM) calculation showed that the beta phase endured a larger deformation amount than alpha phase, which induced a more preferential SRX in beta phase. Meanwhile, the different SRX mechanism between alpha and beta phases caused a different evolution of SRX and grain morphology with increasing annealing temperature. The continuous SRX (cSRX) in alpha phase made the SRX fraction increase and grain size decrease with increasing annealing temperature, with an exception of a grain growth at 940 degrees C. However, SRX occurred in beta phase by subgrain coalescence, which induced the increase of grain size and decrease of SRX fraction with increasing annealing temperature. Conclusively, 880 degrees C was an appropriate annealing temperature to get a uniform and refined microstructure for the hot-rolled TC21 titanium alloy. (C) 2018 Elsevier B.V. All rights reserved.