Dissolution and reprecipitation of 14H-LPSO structure accompanied by dynamic recrystallization in hot-extruded Mg_(89)Y_(4)Zn_(2)Li_(5) alloy  

作　　者：Wei Liu Yu Su Yuntao Zhang Liwen Chen Hua Hou Yuhong Zhao 

机构地区：[1]College of Materials Science and Engineering,North University of China,Taiyuan 030051,China

出　　处：《Journal of Magnesium and Alloys》2023年第4期1408-1421,共14页镁合金学报（英文）

基　　金：the assistance from the Provincial and Ministry Collaborative Innovation Center of Development and Application of High-Performance Aluminum/Magnesium Alloy Materials;the financial supports from the Research Project Supported by Shanxi Scholarship Council of China(No.2021-125);Natural Science Foundation of Shanxi Province(No.20210302124631).

摘　　要：We investigate the variation induced in long-period stacking ordered(LPSO)structures,dynamic recrystallization(DRX),and mechanical performance of hot-extruded Mg89Y4Zn2Li5 alloys fabricated at different extrusion speeds(Ve=0.4,0.8,1.0,1.2 mm/s)and die angles(α=30°,60°,90°)under 400℃,the dissolution and reprecipitation of 14H LPSO structure accompanied by DRX process are then clarified in detail.Upon all extrusion conditions,the block 18R LPSO structures elongate in the extrusion direction,while the lamellar 14H LPSO structures dissolve under the deformation strain.In addition,due to discontinuous and continuous DRX mechanisms,all hot-extruded alloys have a full DRX microstructure consisting of equiaxed recrystallized grains,but the DRX grain size reduces when both extrusion speed and die angle decrease.Note that,in the interior of DRX grains,thin LPSO lamellae mixing 14H,18R and 24R structures nucleate and dynamically precipitate due to the dissolution of the original lamellar 14H LPSO structures.Furthermore,the hot-extruded Mg_(89)Y_(4)Zn_(2)Li_(5)alloy becomes stronger as decreasing of the extrusion speed and die angle,whereas the ductility remains nearly constant.Finally,the hotextruded Mg_(89)Y_(4)Zn_(2)Li_(5)alloy achieves an excellent strength-ductility balance at a relatively low extrusion speed(0.4 mm/s)and small die angle(30°)mainly due to the elongated 18R LPSO structure,fine and full DRX microstructure,thin mixed LPSO precipitates in the DRX grains,twins and dislocations.

关 键 词：Magnesium Extrusion LPSO RECRYSTALLIZATION Precipitation 

分 类 号：TG146.22[一般工业技术—材料科学与工程]