摘要
采用单辊快速凝固法制备了厚度为50—70μm的Cu_(25)Al_(10)Ni_(25)Fe_(20)Co_(20)高熵合金箔材,并研究了其微观结构、抗拉强度、伸长率及电容储能焊特性.结果表明,Cu_(25)Al_(10)Ni_(25)Fe_(20)Co_(20)高熵合金为fcc结构的单一相,快速凝固使合金组织显著细化.在电容储能焊条件下,快速凝固高熵合金箔材点焊接头形成了形态规则的椭球状熔核,熔核形核率较低,晶体依附于母材局部半熔化的晶粒向熔核心部生长,最终形成发达的树枝晶组织;熔合线清晰;与熔核毗邻的母材组织未观察到粗化迹象.电容储能焊条件下,贯穿性裂纹是高熵合金焊接接头中的主要焊接缺陷,其与高熵效应导致的熔核区晶粒粗化、晶体生长方向及电极压力密切相关.
High-entropy alloys are prospective functional and structural materials owing to their excellent electromagnetic and mechanical properties.In this paper,the quenched Cu_（25）Al_（10）Fe_（20）Co_（20）Ni_（25） high-entropy alloy foils with the thickness of 50—70μm were obtained via a single roller experimental apparatus,and the microstructure,tensile strength,elongation and capacitor discharge welding（CDW） characteristics of the alloy were studied.The results show that the high-entropy alloy has a simple single-phase fcc structure,and the microstructure is refined remarkably by rapid solidification.Under CDW condition,the joint with a regular spheroidicity nugget forms. Due to lower nucleation rate and epitaxial growth based on semi-molten grains of base metal to the center of nugget,the microstructure of nugget consists of coarse dendrite crystals.The fusion line is clear between nugget and base metal,and the microstructure adjacent to nugget has no evidence of coarsening.Penetrated crack is the main defect during welding of high-entropy alloy,which relates to grain coarsening and crystal orientation resulting from high-entropy effects as well as electrode press.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第11期1378-1381,共4页
Acta Metallurgica Sinica
基金
陕西省科学技术研究发展计划资助项目2009K06-14~~
关键词
高熵合金
电容储能焊
微观结构
力学性能
high-entropy alloys
capacitor discharge welding
microstructure
mechanical property
