Hot deformation and dynamic recrystallization behaviors of Mg-Gd-Zn alloy with LPSO phases

摘要

The hot deformation and dynamic recrystallization (DRX) behaviors of the homogenized Mg-5.6Gd-0.8Zn (wt.%) alloy with high density lamellar long period stacking ordered (LPSO) phases were investigated. The hot compression tests were conducted at temperatures (T) ranging from 350 degrees C to 500 degrees C and strain rates (epsilon(over dot)) ranging from 0.001 s to 1 to 1 s(-1), by which the hot deformation behavior was characterized by true stress-strain curve and the constitutive equation was calculated. Except for the deformation conditions of T = 350 degrees C and epsilon(over dot) = 0.1-1 s(-1), the true stress-strain curves show DRX characteristics. The LPSO phases had inserted great influences on the deformation and DRX mechanisms of the alloy: (i) when deformed at T = 350-450 degrees C, the LPSO phases had good thermal stability while both twinning and kinking played an important role under various strain rates. The degree of DRX was low and DRXed grains were small. (ii) When deformed at T = 500 degrees C, the LPSO phases were almost melted into the matrix and slip played a dominant role while the degree of DRX was high and its grains were significantly grown. (C) 2019 Elsevier B.V. All rights reserved.