Effect of Cu-Rich Phase Precipitation on the Microstructure and Mechanical Properties of CoCrNiCux Medium-Entropy Alloys Prepared via Laser Directed Energy Deposition
富铜相沉淀对激光定向能量沉积制备的 CoCrNiCux 中熵合金组织和力学性能的影响
レーザー指向性エネルギー堆積によって調製されたCoCrNiCux中エントロピー合金の微細構造と機械的性質に及ぼすCuリッチ相析出の影響
레이저 유도 에너지 증착을 통해 제조된 CoCrNiCux 중간 엔트로피 합금의 미세 구조 및 기계적 특성에 대한 Cu-풍부 상 침전의 영향
Efecto de la precipitación en fase rica en Cu sobre la microestructura y las propiedades mecánicas de las aleaciones de entropía media CoCrNiCux preparadas mediante deposición de energía dirigida por láser
Effet de la précipitation de phase riche en Cu sur la microstructure et les propriétés mécaniques des alliages à entropie moyenne CoCrNiCux préparés par dépôt d'énergie dirigé par laser
Влияние осаждения богатой медью фазы на микроструктуру и механические свойства сплавов со средней энтропией CoCrNiCux, полученных методом лазерного наложения энергии
¹ Shagang School of Iron and Steel, Soochow University, Suzhou, 215131, China
中国 苏州 苏州大学沙钢钢铁学院
² School of Mechanical and Electric Engineering, Soochow University, Suzhou, 215131, China
中国 苏州 苏州大学机电工程学院
Acta Metallurgica Sinica (English Letters), 12 September 2021
Abstract
To shed light into the application potential of high-entropy alloys as "interlayer" materials for Al-steel solid-state joining, we investigated the nature of the CoCrFeMnNi/Fe and CoCrFeMnNi/Al solid/solid interfaces, focusing on the bonding behavior and phase components. Good metallurgical bonding without the formation of hard and brittle IMC can be achieved for CoCrFeMnNi/Fe solid/solid interface.
In contrast to the formation of Al₅Fe₂ phase at the Fe/Al interface, Al₁₃Fe₄-type IMC, in which the Fe site is co-occupied equally by Co, Cr, Fe, Mn and Ni, dominates the CoCrFeMnNi/Al interface. Although the formation of IMC at the CoCrFeMnNi/Al interface is not avoidable, the thickness and hardness of the Al₁₃(CoCrFeMnNi)₄ phase formed at the CoCrFeMnNi/Al interface are significantly lower than the Al₅Fe₂ phase formed at the Fe/Al interface. The activation energies for the interdiffusion of Fe/Al and CoCrFeMnNi/Al static diffusion couple are 341.6 kJ/mol and 329.5 kJ/mol, respectively.
Despite this similarity, under identical static annealing condition, the interdiffusion coefficient of the CoCrFeMnNi/Al diffusion couple is significantly lower than that of the Fe/Al diffusion couple. This is thus mainly a result of the reduced atomic mobility/diffusivity caused by the compositional complexity in CoCrFeMnNi high-entropy alloy.