@article{Ren2025, 
author = {Lingbao Ren and Yurong Zhao and Jinjin Li and Fei Liu and Boyu Liu and Ge Wu and Carl J. Boehlert and Zhiwei Shan},
title = {Inhibiting creep in fine-grained Mg–Al alloys through grain boundary stabilization},
year = {2025},
journal = {Journal of Magnesium and Alloys},
volume = {13},
number = {5},
pages = {2072-2083},
keywords = {Segregation, Creep, Microalloying, Wrought Mg alloys, Discontinuous precipitation},
url = {https://www.sciopen.com/article/10.1016/j.jma.2024.04.033},
doi = {10.1016/j.jma.2024.04.033},
abstract = {The limited creep resistance of wrought Mg–Al alloys restricts their lightweight applications at intermediate temperatures due to the softening effect of discontinuous precipitation (DP) on the dislocation-controlled creep. Here, we developed a creep-resistant wrought Mg–Al alloy through microalloying of Y and Ca. The resulting alloy exhibited an order of magnitude enhancement in the creep resistance at 125 ℃/50–100 MPa. In contrast to the grain boundary instabilities by DP in the previously reported wrought Mg–Al alloys, we show that the addition of 0.21Y+0.15Ca wt% produces a (Zn+Ca) co-segregation at the grain boundaries as a result of their segregation energy and the activation energy of grain boundary migration, thereby stabilizing the grain boundaries. The (Zn+Ca) co-segregation inhibits the dynamic DP and promotes the formation of intragranular Al-enriched clusters, which favorthe formation of Al2Y, Mg17Al12 nano precipitates, thereby impeding intragranular dislocation motion during creep. Furthermore, the addition of 0.21Y+0.15Ca wt% facilitates the formation of a fine and uniform recrystallization structure in the microalloyed alloys compared to AZ80 due to the high activation energy of mobility for the (Zn+Ca) segregated grain boundary. Therefore, the microalloyed alloys exhibit good tensile properties with 380 MPa tensile strength and 18% elongation. Our constitutive analysis revealed that the (Y+Ca) microalloying decreased the creep stress exponent by 29% and increased the creep resistance in the medium to high-stress range. Microalloying provides a promising way to develop low-cost creep-resistant wrought Mg–Al alloys.}
}