Achieving outstanding heat-resistant properties in Mg alloy via constructing stable solute-network

Abstract

A new Mg–Sm–Ce–Mn-based alloying system with a large miscibility gap was uncovered, and multi-solute co-segregations at high-angular grain boundaries (HAGBs), dislocations and low-angular grain boundaries (LAGBs) are obtained after the proper extrusion process. During following long-term thermal exposure, the solute along HAGBs gradually evolves into nano-precipitates, while the precipitation process along LAGBs is obviously suppressed due to the intrinsically low-energy character, and numerous G. P. zones and γ” phases are formed in deformed regions, which always keep the limited size and reticular distribution. Consequently, the bimodal-grain structure is thermally stable, and the excellent high-temperature strength can be well maintained.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

A new strategy of constructing a stable solute-network to achieve outstanding heat-resistant properties can be realized in low-alloyed Mg wrought alloy, and high-temperature UTS (∼291 MPa) can even exceed conventional Mg-RE alloys.

KEYWORDS:

• Mg wrought alloy
• heat resistance
• segregation
• precipitation
• strengthening

Acknowledgment

This work is supported by the National Key Research and Development Program of China (2021YFB3701002), the National Natural Science Foundation of China (Nos. U2167213 and 51971053). H.C. Pan acknowledges the financial assistance from Young Elite Scientists Sponsorship Program by China Association for Science and Technology (2019-2021QNRC001-003), and the fund from the Fundamental Research Funds for the Central Universities (N2202020). Special thanks are due to Dr. Na Xiao in the Analytical and Testing Center of Northeastern University for the assistance with EBSD analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Key Research and Development Program of China: [Grant Number 2021YFB3701002]; National Natural Science Foundation of China: [Grant Number 51971053,U2167213]; Fundamental Research Funds for the Central Universities: [Grant Number N2202020]; Young Elite Scientists Sponsorship Program by CAST: [Grant Number 2019-2021QNRC001,2019-2021QNRC002,2019-2021QNRC003].