lEffect of the primary O phase on thermal deformation behavior of a Ti2AlNb-based alloy

The effect of primary O phase on thermal compressive deformation behavior of a Ti2AlNb-based alloy are investigated at temperatures from 990 degrees C to 1020 degrees C and strain rate range from 0.001 s(-1) to 1 s(-1). The results indicated that the primary O phase has a significant effect on the hot deformation behavior of the studied alloy. The peak stress and the degree of the stress descent of the specimen with primary O lath and Widmanstatten O + B2 structures are higher than those of the specimen with Widmanstatten O + B2 structures under higher strain rate. Besides, both the critical stress and critical strain for the onset of dynamic recrystallization (DRX) of the studied alloy upsurge with increasing the strain rate or decreasing the deformation temperature. The specimen with primary O lath and Widmanstatten O + B2 structures exhibits greater critical stress and critical strain than the specimen with Widmanstatten O + B2 structures. The strain rate sensitivity exponents of the investigated alloy with primary O lath and Widmanstatten O + B2 structures is higher than that of the alloy with Widmanst_atten O + B2 structures at low temperature (990 degrees C), while the reverse is true at high temperature (1020 degrees C). Beyond that, the DRX mechanisms of the explored alloys with different morphologies of O phase were also investigated by EBSD and TEM analysis. (C) 2020 Elsevier B.V. All rights reserved.