Study on the preparation principle and strengthening mechanism of in-situ synthesized Mg-Li matrix composites through the La_(2)O_(3)→La→Al_(m)La_(n)routeOA
In this study,low-cost La_(2)O_(3)powder modified with LiF-LiCl flux was used as a precursor and introduced into Mg-5Li-3Al-2Zn(LAZ532)alloy melt.Through a series of reactions,in-situ formed Al_(m)La_(n)phase-reinforced LAZ532 matrix composites were successfully prepared.The surface modification of La_(2)O_(3)powder by molten salt and the related reduction reaction mechanism in the alloy melt,as well as the effects of different La_(2)O_(3)additions on the microstructure and mechanical properties of the composites,were systematically investigated.First-principles calculations revealed that during precursor preparation,the Cl/F heteroatoms in the flux chemically destabilize La-O bonds,forming LaOF/LaOCl intermediates.Subsequently,Li atoms with low electronegativity and high reactivity in the melt preferentially combined with O/Cl/F,driving the reduction reactions.The reduced La then preferentially bonded with Al,predominantly forming the stable Al3La phase,along with small amounts of Al11La3 and Al2La phases.Microstructural analysis showed that as the La_(2)O_(3)content increased from 0.3%to 2.0 wt.%,the yield rate of La in the composite rose from 8%to 23%.Furthermore,the dispersed micro/nano-sized Al_(m)La_(n)phases formed an atomically bonded interface with the matrix,and their size initially decreased and then slightly increased with increasing volume fraction.These phases promoted recrystallization through heterogeneous nucleation and grain boundary pinning,leading to texture weakening and grain refinement in the composites.The mechanical properties of the composites first improved and then deteriorated with increasing La_(2)O_(3)addition.Among them,the composite with 0.7 wt.%La_(2)O_(3)exhibited excellent comprehensive mechanical properties,with tensile strength,yield strength,and elongation reaching 278.3 MPa,182.5 MPa,and 23.6%,respectively.The enhancement in yield strength was mainly attributed to the synergistic effects of grain refinement,precipitation strengthening,and texture strengthening.This study offers a novel design concept for in-situ synthesized Mg-Li matrix composites,holding significant scientific value.
Xiaoqiang Li;Xinlian He;Junze Zhang;Daohe Zhang;Dandan Li;Qichi Le;Jinhui Wang;Dexue Liu
School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China Salt Lake Chemical Engineering Research Complex,Qinghai University,Xining 810016,China Key Laboratory of Salt Lake Chemical Material of Qinghai Province,Xining 810016,ChinaSchool of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,ChinaSchool of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,ChinaSchool of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,ChinaSchool of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,ChinaKey Laboratory of Electromagnetic Processing of Materials,Ministry of Education,Northeastern University,Shenyang 110819,ChinaSalt Lake Chemical Engineering Research Complex,Qinghai University,Xining 810016,China Key Laboratory of Salt Lake Chemical Material of Qinghai Province,Xining 810016,ChinaSchool of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China School of Materials Science and Engineering,Xi’an Shiyou University,Xian 710065,China
通用工业技术
Mg-Li matrix compositesLa_(2)O_(3)powderIn situ synthesisPreparation principleStrengthening mechanism
《Journal of Magnesium and Alloys》 2026 (6)
P.505-520,16
financially supported by the Natural Science Foundation for Young Scientists of Gansu Province(grant no.25JRRA103)the Open Project of Salt Lake Chemical Engineering Research Complex,Qinghai University(grant no.2024-DXSSKF-04)Lanzhou University of Technology Projects for Research Initiation and Interdisciplinary Cultivation Exploration for Young Faculty and Postdoctoral Fellows(grant no.062603,062513 and 2A1187).
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