What question did this study set out to answer?

The aim is to explore a cost-effective strategy for enhancing the strength of low-rare-earth magnesium alloys.

April 3, 2026Journal of Materials Research and Technology0 citationsOpen Access

High-efficiency strengthening achieved by ultra small-sized and orientation-controlled precipitates in low-rare-earth Mg-Gd-Y-Zr alloys

YZY. G. ZhangTaiyuan University of Technology HNHuihui NieTaiyuan University of Technology HCHongsheng ChenHarbin Institute of Technology

Key Points

The aim is to explore a cost-effective strategy for enhancing the strength of low-rare-earth magnesium alloys.
Selected Mg-5.3Gd-4.1Y-0.13Zr alloy with <10% wt. rare earth content.
Investigated the effects of aging at 200°C for 32 hours.
Analyzed precipitate formation and their impact on dislocation behavior.
Ultimate tensile strength reached 521 MPa after aging.
Strengthening efficiency measured at 12.5 times more than typical Mg-containing rare earth alloys.
Small-sized β' precipitates increased dislocation strengthening and improved precipitation efficiency.

Abstract

High-rare-earth (HRE) magnesium alloys typically enhance strengthening by increasing rare earth (RE) content, but this strategy yields limited efficacy and high cost. In this study, a low-rare-earth (LRE) alloy, Mg-5.3Gd-4.1Y-0.13Zr (<10% wt.) was selected to explore a novel and efficiency strategy of fabricating high-strength LRE Mg alloy. A large cube-shaped compound is observed at grain boundaries, which gradually grows via absorbing dislocations and RE elements during aging period, resulting in a softening effect near the grain boundaries. Despite LRE and softening, the peak-aged(200°C,32h) ultimate tensile strength (UTS) reaches 521 MPa, which is higher than that of most Mg-(9∼15%) RE alloys, which achieves a significant aging strengthening efficiency, 12.5 times that of others. The main strengthening mechanisms originate from several aspects: first, the small-sized(5.7nm) and high-density β' precipitates(3.8%) lower the strengthening threshold and improve the efficiency of precipitation strengthening; second, precipitation-coupled twinning changes the orientation of some β' precipitates, making them orthogonal to each other, leading to a superior strengthening effect compared to single prismatic-plane precipitation; third, the precipitates formed during aging promote continuous dislocation multiplication, resulting in a high dislocation volume fraction and introducing substantial dislocation strengthening. This work paves the way for designing strengthening strategies for magnesium alloys with similar precipitation sequences.

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