Post-fire residual service performance of magnesium alloys reinforced by rare earths  

作　　者：Jiaxuan Han Bo Hu Zhenfei Jiang Mingdi Yu Fanjin Yao Zixin Li Bensong Chen Wanzhang Yang Dejiang Li Xiaoqin Zeng Wenjiang Ding 

机构地区：[1]National Engineering Research Center of Light Alloy Net Forming and the State Key Laboratory of Metal Matrix Composites,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai,200240,China [2]Yunnan Aluminium Co.,Ltd.,Kunming,650500,China

出　　处：《Journal of Rare Earths》2024年第12期2374-2384,I0007,共12页稀土学报（英文版）

基　　金：Project supported by the National Key Research and Development Program of China(2021YFB3501002);the National Science and Technology Major Project(J2019-Ⅷ-0003-0165);the National Natural Science Foundation of China(52301059);the Shanghai Post-doctoral Excellence Program(2023372)。

摘　　要：The flammability of magnesium alloys continues to be a significant barrier to their extensive application,and alloying with rare earth elements(REs)is an effective way to enhance the ignition and fire resistance of Mg alloys.Three commercial as-extruded Mg alloys(AZ80 and two Mg-RE alloys:EZ30K and WE43)were directly exposed to flame heating for revealing the evolutions of microstructure and mechanical properties,which is valuable in assessing the post-fire residual service performance of Mg alloy components.Results show that secondary phase dissolution,grain growth,grain boundary melting,alloy melting,and defects generation successively occur during the heating process.After short-term heating for 30 s,the elongation of AZ80 alloy increases significantly by 214%,from 3.82%to 12.01%,with minimal change in strength compared to the initial unheated state.This transformation is attributed to the recovery,grain growth,Mg17Al12 dissolution and dislocation density reduction.Conversely,EZ30K and WE43 alloys exhibit minimal changes in mechanical properties after short-term heating for 60 s,attributed to the pinning effect of REs.However,in subsequent heating states,resolidified microstructure and the presence of defects lead to a noteworthy decrease in both strength and elongation.Among these three alloys,the fire resistance follows this ranking:EZ30K>WE43>AZ80,primarily due to the high thermal conductivity of EZ30K alloy and the thermal stability improved by the addition of REs.

关 键 词：Magnesium alloys Rare earths FIRE Residual service performance Microstructure Mechanical properties 

分 类 号：TG146.22[一般工业技术—材料科学与工程]