摘要
采用OM、扫描电镜、维氏硬度计和拉伸试验机研究了大塑性变形条件下稀土La对8021铝箔坯料组织及性能的影响。结果表明:稀土La可增加凝固过程中的晶核数量,可以显著细化晶粒。稀土La比Al具有更大的空位结合能,抑制了Al原子向空位进行热扩散,使得再结晶晶粒的尺寸较小。添加稀土La后在粒子表面含形成了富稀土膜层,抑制了Fe原子的扩散行为,使得退火过程中富铁相粒子沿长度方向的生长动力不足。轧制变形后原本的针状富铁相粒子在剪应力作用下断裂成几段,经退火处理后,断裂后的针状富铁相粒子逐渐粗化,最终演化成短杆状的细小粒子,均匀分布于晶界。稀土La能显著细化铸态组织,又能抑制退火时的晶粒长大,提升了合金的抗拉强度、延伸率和显微硬度。同时短棒状富铁相可以钉扎更多的位错,更能承受拉伸过程中所产生的剪切应力,能够更好的协调塑性变形,提高了合金的延伸率。
The effects of rare earth La on the microstructure and properties of 8021 aluminum foil blank under large plastic deformation are studied by OM,SEM,vickers hardness tester and Tensile testing machine.The results show that rare earth La can increase the number of crystal nucleus during the solidification process and significantly refine the grains.Rare earth La has greater vacancy binding energy than Al,which inhibits Al atoms thermal diffusing to vacancies and makes the size of recrystallized grains smaller.After adding rare earth La,a film with rich rare earth is formed on the particle surface,which inhibits the diffusion behavior of Fe atoms and leads the growth momentum of iron-rich particles in the length direction insufficient during annealing.After rolling deformation,the original needle-like iron-rich phase particles are broken into several sections under shear stress.After annealing,the broken needle-like iron-rich phase particles gradually coarsen and eventually evolve into short rod-shaped fine particles,which are evenly distributed at grain boundaries.Rare earth La can significantly refine the as-cast structure and inhibit the grain growth during annealing,thus improving the tensile strength,elongation,and microhardness of the alloy.At the same time,the short rod-shaped iron-rich phase can anchor more dislocations and more capable to withstand the shear stress during the tensile process,can better coordinate the plastic deformation and improve the elongation of the alloy.
作者
谭国寅
TAN Guoyin(Kunming Metallurgical Research Institute Co.,Ltd.,Kunming 650031,Yunnan,China)
出处
《金属功能材料》
CAS
2024年第2期114-118,共5页
Metallic Functional Materials
基金
云南省重大科技专项计划(202202AB080004)。
关键词
大塑性变形
富铁相粒子
再结晶
组织与性能
large plastic deformation
iron-rich phase particles
recrystallization
microstructure and properties
