新型Mg-Bi-Al-Zn变形镁合金的微观组织与力学性能

发布时间：2018-11-25 08:35

【摘要】：基于开发低成本非稀土型变形镁合金的目的,利用XRD、SEM、EDS、TEM和EBSD等检测手段对新型Mg-7Bi-1Al-1Zn(质量分数,%,BAZ711)合金的微观组织进行相关表征,同时采用万能试验机测试了其铸态及挤压态试样的力学性能。结果表明:铸态BAZ711合金中粗大的Mg_3Bi_2相呈连续网状分布于α-Mg枝晶晶界处,其平均二次枝晶臂间距约为50μm;挤压态BAZ711合金发生完全再结晶,平均晶粒尺寸减小为3μm,微米级Mg_3Bi_2相沿挤压方向呈条带状断续分布,同时,基体中弥散分布有大量50~200 nm的近球状或短杆状Mg_3Bi_2相;挤压后合金表现出典型挤压织构特征。由于组织细化和微/纳双尺度第二相的综合强化作用,挤压态合金力学性能较铸态显著提高,其拉伸屈服强度、抗拉强度和伸长率分别达到244 MPa、305 MPa和14%。
[Abstract]:For the purpose of developing low cost non-rare earth wrought magnesium alloys, the microstructure of new Mg-7Bi-1Al-1Zn (mass fraction,%, BAZ711) alloys was characterized by XRD,SEM,EDS,TEM and EBSD. At the same time, the mechanical properties of as-cast and extruded samples were tested by universal testing machine. The results show that the coarse Mg_3Bi_2 phase in the as-cast BAZ711 alloy is distributed in a continuous network at the 伪-Mg dendrite boundary, and the average secondary dendritic arm spacing is about 50 渭 m. The extruded BAZ711 alloy is recrystallized completely and the average grain size decreases to 3 渭 m. The micrometer Mg_3Bi_2 phase distributes along the extruding direction in a strip-like manner, and at the same time, the average grain size decreases to 3 渭 m. A large number of subspherical or short rod-like Mg_3Bi_2 phases of 50 ~ 200 nm were distributed in the matrix. The extruded alloy shows typical extrusion texture. The mechanical properties of the extruded alloy are significantly improved than that of the as-cast alloy due to the effect of microstructure refinement and micro- / nanoscale second phase strengthening. The tensile yield strength, tensile strength and elongation of the extruded alloy are up to 244 MPa,305 MPa and 14%, respectively.
【作者单位】：河北工业大学材料科学与工程学院;韩国材料科学研究院轻合金组;山东理工大学材料科学与工程学院;江苏科技大学冶金与材料学院;
【基金】：河北省教育厅基金资助项目(QN2015035) 河北省研究生创新项目(220056) 河北工业大学优秀青年科技创新基金资助项目(2015002);河北工业大学引进人才项目(208002) 河北省自然科学基金优秀青年科学基金资助项目(E2016202130) 科技部“中韩青年科学家”交流计划资助项目(201510)~~
【分类号】：TG146.22

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