Deformation Mechanism and Constitutive Consideration for Ti-5Al-5Mo-5V-3Cr-1Zr Alloy Compressed at Elevated Temperatures
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JMEPEG https://doi.org/10.1007/s11665-020-04929-0
Deformation Mechanism and Constitutive Consideration for Ti-5Al-5Mo-5V-3Cr-1Zr Alloy Compressed at Elevated Temperatures Yuting Zhou, Jie Zhou
, Qian Shu, Shishan Li, Fanjiao Gongye, Shuai Long, and Heping Deng
(Submitted April 6, 2020; in revised form May 26, 2020) To investigate hot deformation behavior of a Ti55531 alloy, a series of isothermal compression tests were performed on a Gleeble-3500 simulator at the temperature range of 1033–1153 K and constant strain rates of 0.001–1 s21. Based on the experimental flow stress data, processing map and grain morphology, the deformation mechanism map was summarized. In this study, the dominant microstructural mechanism processed near or above b-transus temperature was considered to be deformation characteristic of b phase, where dynamic recovery was in dominant and at mediate strain rate dynamic recrystallization was also observed. Superplasticity was found at 1003–1033 K and 0.001 s21, correlating with dislocation glide and grain boundary slide (GBS). Undesirable plastic flow such as flow localization and flow rotation was found at high strain rate of 0.1-1 s21 and at the entire test temperature range. The optimum working window of this alloy was finally obtained at 1003–1063 K and 1093–1153 K and at 0.001–0.1 s21. Keywords
activation energy, deformation mechanism map, microstructural observation, strain rate sensitivity, Ti55531 alloy
1. Introduction Near-b Titanium alloys have good workability, high fatigue and corrosion resistance, and superior balance of mechanical properties, resulting in their widespread use in producing critical components for aerospace, automotive, and offshore industry (Ref 1, 2). Many publications (Ref 3-5) have reported that processing parameters and grain morphology have significant effects on the deformation behavior of near-b Titanium alloys. In this regard, processing maps accommodated by isothermal compression tests are usually applied to characterize the microstructural mechanisms under different deformation conditions for adjusting mechanical properties and obtaining appropriate microstructures. For example, Seshacharyulu et al. (Ref 6) previously performed a process map and estimated the apparent activation energies on the basis of experimental flow stress data to determine the deformation mechanisms of Ti-6Al4V in a + b phase field and b phase field. Fan et al. (Ref 7) investigated the mechanism of microstructural evolution in Ti7333 alloy through constructing processing map. It has concluded that, the microstructural changes of this material were controlled by dynamic recovery, dynamic recrystallization, superplasticity and spheroidization of a grains. Stable plastic flow domain exhibited at 1043–1243 K and 0.001–1 s1 with high efficiency in power dissipation about 60%. Based on Yuting Zhou, Jie Zhou, Qian Shu, Shishan Li, Fanjiao Gongye, Shuai Long, and Heping Deng, School of Material Science and Engineering, Chongqing University, Chongqing 400044, China. Contact e-mails: zhouyuting@cq
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