Ce和Zr对新型Al-Cu-Li合金微观组织与拉伸性能的影响（英文）

Effects of Cerium and Zirconium Microalloying Addition on the Microstructures and Tensile Properties of Novel Al-Cu-Li Alloys

通过微观观察和拉伸测试的手段,对比研究了在一种高Cu/Li比的新型Al-5.8Cu-1.3Li合金(质量分数,%)中分别加入Ce,Zr或者两者共同添加对其合金微观组织与力学性能的影响。微观观察表明:Ce和Zr共同添加合金与单一添加Ce或者Zr的合金比较,金属间化物弥散体由粗大的多边形颗粒转变成无规则的细小粒子,相应的拉伸断口断裂模式由脆性的沿晶断裂向塑性穿晶断裂转变。进一步微观分析表明:Ce的添加促进了Al-Cu-Li合金中主要强化相T1的析出。Ce和Zr共同添加合金与单一添加Ce合金相比,由于相对较少的Cu被束缚在尺寸较小的AlC uC e弥散体中,该合金基体中的Cu过饱和度在固溶淬火后相对更高。因此,Al-Cu-Li-Ce-Zr合金与Al-Cu-Li-Ce合金相比较,其析出相种类向T1转变,尺寸变得更小,晶粒更加细化,从而导致了该合金在峰时效时抗拉强度和屈服强度分别相对提高了19.6%和16.1%,并具有与之相当的延伸率。

Effects of Ce and Zr additions（combinative addition and single addition） on the microstructures and tensile properties of novel Al-5.8wt%Cu-1.3wt%Li alloys with an elevated Cu/Li ratio were investigated comparatively by a microscopy method and tensile test. The microstructural observation shows that the intermetallic dispersoid in the case of combinative addition of Ce and Zr is more significantly refined from coarse polygonal shape to fine irregular particles compared to that in the case of single addition of Ce or Zr. Due to the refinement and the modification of intermetallic dispersoid, the corresponding fracture mode changes from brittle intergranular fracture to ductile transgranular fracture during tension. In addition, microstructural analysis reveals that the addition of Ce promotes the precipitation of the T_1 phase which is the predominant strengthening phase in Al-Cu-Li alloy. In comparison to Ce containing Al-Cu-Li alloy, Ce＋Zr-containing Al-Cu-Li alloy raises the degree of supersaturation of Cu in matrix due to less Cu atoms being trapped in finer AlCu Ce dispersoid after solution treatment. Thus it is found that the ultimate tensile strength（UTS） and yield strength（YS） for the later alloy are increased by 19.6% and 16.1%, respectively. And the elongation（El） is similar, owing to decreasing of the phase size, changing of precipitation type to T_1 phase only and further grain refinement.