摘要
通过添加碱土元素Ca和稀土元素Ce,结合挤压工艺制备了适用于轨道客车的新型挤压态Mg-6Al-Zn-1.7Ca-0.5Ce-0.3Mn合金板材。合金在加工过程中发生了显著的动态再结晶形核过程,经过热挤压后板材中形成了异质结构,并伴有强的基面织构;组织中分布有大量的微米级和纳米级第二相。透射电镜分析结果表明,在变形过程中粗大变形晶粒和细小的动态再结晶晶粒内部形成了高密度位错、层错和小角度晶界。沿板材挤压方向屈服强度为230.45 MPa,抗拉强度为273.85 MPa,伸长率为5.08%。织构强化、细晶强化、异构强化和第二相强化为合金的主要强化机制,但是粗大的微米级第二相和强基面织构导致板材的伸长率较低。经燃点测试,合金的燃点为840℃。高温氧化实验结果表明,稀土元素Ce和碱土元素Ca起主要的阻燃作用。
A novel as-extruded Mg-6Al-Zn-1.7Ca-0.5Ce-0.3Mn alloy sheet suitable for rail vehicles was fabricated by adding alkaline earth element Ca and rare earth element Ce combined with an extrusion process.During processing,significant dynamic recrystallization nucleation occurred,and a heterogeneous structure with a strong basal texture was formed after hot extrusion.The microstructure contained a large number of micron-and nano-sized second-phase particles.Transmission electron microscopy(TEM)analysis reveals that high-density dislocations,stacking faults and low-angle grain boundaries were formed within both coarse deformed grains and fine dynamically recrystallized grains during deformation.Along the extrusion direction,the alloy exhibits the yield strength of 230.45 MPa,the ultimate tensile strength of 273.85 MPa,and the elongation of 5.08%.The primary strengthening mechanisms include texture strengthening,grain refinement strengthening,hetero-deformation-induced strengthening and second-phase strengthening.However,the coarse micron-sized second phases and strong basal texture result in relatively low ductility.Ignition point testing results show that the ignition temperature of alloy is 840℃.High-temperature oxidation experiments results confirm that the rare earth element Ce and alkaline earth element Ca play a dominant role in flame retardancy.
作者
徐涵
王胜
马国强
董飞虎
薛春
王子
程丽任
车朝杰
楚志兵
XU Han;WANG Sheng;MA Guo-qiang;DONG Fei-hu;XUE Chun;WANG Zi;CHENG Li-ren;CHE Chao-jie;CHU Zhi-bing(Department of Materials Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;State Key Laboratory of Rare Earth Resources Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;Department of Materials Science and Engineering,Harbin Engineering University,Harbin 150001,China;Jilin Province Product Quality Supervision and Inspection Institute,Changchun 130103,China)
出处
《塑性工程学报》
北大核心
2025年第10期246-258,共13页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(521353)
山西省科技重大专项计划“揭榜挂帅”项目(202101110401009)
长春市科技发展计划(21GD03)
吉林省科技发展计划(SK2202302038)。
