Dynamic recrystallization behavior of an as-cast TiAl alloy during hot compression

被引:69
作者
Li, Jianbo [1 ]
Liu, Yong [1 ]
Wang, Yan [2 ]
Liu, Bin [1 ]
He, Yuehui [1 ]
机构
[1] Cent S Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China
[2] Cent S Univ, Sch Aeronaut & Astronaut, Changsha 410083, Hunan, Peoples R China
基金
中国国家自然科学基金;
关键词
TiAl alloy; Hot deformation; Constitutive equation; Dynamic recrystallization; TEMPERATURE DEFORMATION-BEHAVIOR; TITANIUM ALUMINIDE ALLOYS; HIGH NB; EVOLUTION; KINETICS; DESIGN; FLOW;
D O I
10.1016/j.matchar.2014.09.013
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
High temperature compressive deformation behaviors of as-cast Ti-43Al-4Nb-1.4W-0.6B alloy were investigated at temperatures ranging from 1050 degrees C to 1200 degrees C, and strain rates from 0.001 s(-1) to 1 s(-1). Electron back scattered diffraction technique, scanning electron microscopy and transmission electron microscopy were employed to investigate the microstructural evolutions and nucleation mechanisms of the dynamic reaystallization. The results indicated that the true stress-true strain curves show a dynamic flow softening behavior. The dependence of the peak stress on the deformation temperature and the strain rate can well be expressed by a hyperbolic-sine type equation. The activation energy decreases with increasing the strain. The size of the dynamically recrystallized beta grains decreases with increasing the value of the Zener-Hollomon parameter (Z). When the flow stress reaches a steady state, the size of beta grains almost remains constant with increasing the deformation strain. The continuous dynamic recrystallization plays a dominant role in the deformation. In order to characterize the evolution of dynamic recrystallization volume fraction, the dynamic recrystallization kinetics was studied by Avrami-type equation. Besides, the role of beta phase and the softening mechanism during the hot deformation was also discussed in details. (C) 2014 Elsevier Inc. All rights reserved.
引用
收藏
页码:169 / 177
页数:9
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