Hot deformation behavior and microstructure evolution of Ti-38644 titanium alloy

doi:10.13251/j.issn.0254-6051.2025.03.032

Abstract

Abstract: Isothermal thermal compression tests of metastable β titanium alloy Ti-38644 with the strain rate of 0.01-50 s^-1and reduction of 60% at the temperature between 800-1000 ℃ were carried out by a Gleeble-3800 thermal simulation machine. The flow stress curves under different deformation conditions were analyzed to establish the Arrhenius constitutive model and processing maps of the Ti-38644 titanium alloy, and the effect of deformation parameters on the microstructure evolution was systematically studied. The results show that with the increase of strain, the flow curves successively present work hardening and dynamic softening, and the discontinuous yielding occurs after the peak stress. The flow stress decreases as the deformation temperature increases and the strain rate decreases. Combined with the hot processing map, it is found that the instability region is mainly concentrated in the high strain rate area, and the peak efficiency of power dissipation (η) region occurs in the temperature range of 840-1000 ℃ and the strain rate of 0.01-0.1 s^-1, meanwhile the microstructure shows dynamic recrystallization characteristics.

Key words: Ti-38644 titanium alloy, thermal compression, flow curves, microstructure, dynamic recrystallization

CLC Number:

TG146.2

Dong Entao, Teng Aijun, Fang Qiang, Chen Xin, Dai Guanglin, Kang Qiang, Wang Peng, Geng Naitao. Hot deformation behavior and microstructure evolution of Ti-38644 titanium alloy[J]. Heat Treatment of Metals, 2025, 50(3): 201-207.

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