TY  - JOUR
AU  - Li, Jingli
AU  - Wen, Chen
AU  - Han, Xiuzhu
PY  - 2025
TI  - Unveiling anomalous strengthening and deformation mechanism evolution in a Mg-Gd-Y-Zr alloy under rate-temperature coupling effects
JO  - Journal of Magnesium and Alloys
SN  - 2213-9567
SP  - 2913
EP  - 2926
VL  - 13
IS  - 6
AB  - While the deformation behavior of rare-earth magnesium alloys at high temperatures has been extensively studied, the deformation mechanisms under moderate-to-low temperatures and high strain rates remain insufficiently understood. To address this gap, hot compression tests were conducted on a Mg-11Gd-3Y-0.5Zr (wt.%) alloy over a temperature range of 150 ℃–450 ℃ under strain rates of 10−3 s−1 (low strain rate (LSR)) and 10 s−1 (high strain rate (HSR)) to explore the strain rate-temperature coupling effects during hot deformation. The results revealed an anomalous increase in peak stress at 150 ℃–250 ℃ as the strain rate decreased, attributed to the combined effects of nano-precipitates, dislocation cell structures, and serrated flow induced by dynamic strain aging. At higher temperatures, strain rate influences softening pathways: under HSR at 450 ℃, the effect of twinning shifts from strengthening to facilitating dynamic recrystallization (DRX), resulting in substantial grain refinement (~4 µm, 81% area fraction at a strain of 0.6). In contrast, at LSR, softening is dominated by dynamic recovery at 350 ℃, with limited DRX (~4 µm grains, 10% area fraction at a strain of 0.6) occurs at 400 ℃. These findings clarify the dual role of twinning and its interaction with rate-temperature conditions, providing valuable insights into optimizing the hot processing of rare-earth magnesium alloys.
UR  - https://doi.org/10.1016/j.jma.2025.03.018
DO  - 10.1016/j.jma.2025.03.018