Deformation mechanism diagram of a Ti-2.5Zr-2Al titanium alloy forged in the α plus β region and grain refinement

The alpha+beta forging is a key pass for the hot forging process of a Ti-2.5Zr-2Al titanium alloy. In this paper, the hot deformation mechanism of a Ti-2.5Zr-2Al titanium alloy was obtained by the double-cone compression test, which provides a theoretical basis for designing reasonable alpha+beta forging process to obtain ideal microstructure. A wide range of gradient strains and corresponding microstructure were obtained by using the double-cone compression test. The double-cone compression process was simulated by the finite element software. Electron backscatter diffraction technique (EBSD) and transmission electron microscope (TEM) were used to characterize the deformed microstructure of the double-cone specimen. The hot deformation mechanism diagram in the strain range of 0.2-1.2 and the temperature range of 700 degrees C-850 degrees C was constructed. At 800 degrees C, in the low strain region (<0.476), the main deformation mechanism is dynamic recovery (DRV), and continuous dynamic recrystallization (CDRX) begins to occur. In the medium strain region (0.476-1.006), the deformation mechanism is mainly CDRX, accompanied by a small amount of the deformation bands (DBs). Nevertheless, in the large strain region (>1.006), a large number of the DBs occur. The ultra-fine grains with an average size of about 0.46 um were obtained according to the hot compression under the strain of about 0.717 at 800 degrees C. The ultra grain refinement mechanism during hot deformation was summarized.

Automated summary

The hot deformation mechanism of a Ti-2.5Zr-2Al titanium alloy was investigated using the double-cone compression test, providing a theoretical basis for designing an optimal alpha+beta forging process. Ultra-fine grains were obtained through hot compression at 800 degrees C, with a detailed analysis of the deformation mechanisms involved.