摘要
High-entropy alloy composites(HEACs)have attracted significant attention due to their exceptional mechanical properties and chemical stability.By adjusting the content of reinforcing particles in the high-entropy alloy and by employing advanced additive manufacturing techniques,high-performance HEACs can be fabricated.However,there is still considerable room for improvement in their performance.In this study,CoCrFeMnNi HEA powders were used as the matrix,and NiCoFeAlTi high-entropy intermetallic powders were used as the high-entropy reinforcement(HER).CoCrFeMnNi/NiCoFeAlTi HEACs were fabricated using selective laser melting technology.The study results indicate that after aging,the microstructure of HEACs with HER exhibits Al-and Ti-rich nano-oxide precipitates with an orthorhombic CMCM type structure system.After aging at 873 K for 2 h,HEACs with HER achieved excellent overall mechanical properties,with an ultimate tensile strength of 731 MPa.This is attributed to the combined and synergistic effects of precipitation strengthening,dislocation strengthening,and the high lattice distortion caused by high intragranular defects,which provide a multi-scale strengthening and hardening mechanism for the plastic deformation of HEACs with HER.This study demonstrates that aging plays a crucial role in controlling the precipitate phases in complex multi-element alloys.
高熵合金复合材料以其优异的力学性能和化学稳定性而备受关注。通过调节增强体颗粒的含量以及结合先进的增材制造技术,可以获得优异性能的高熵合金复合材料。本研究旨在通过选择性激光熔化和短时时效处理,制备出具有优异力学性能的CoCrFeMnNi/NiCoFeAlTi高熵合金复合材料。研究结果表明,时效处理后,高熵合金复合材料析出一种正交CMCM型结构体系的富含Al、Ti的纳米氧化物。高熵合金复合材料在经873K时效处理2h后获得了优异的力学性能,极限抗拉强度达到731 MPa。这归因于沉淀强化、位错强化以及晶内缺陷导致的高晶格畸变的共同协调效应,为高熵合金复合材料的塑性变形提供了一个多尺度的强化和硬化机制。研究表明,时效处理对调控复杂元合金析出相具有重要意义。
基金
Project supported by ClassⅢPeak Discipline of Shanghai-Materials Science and Engineering(High-Energy Beam Intelligent Processing and Green Manufacturing),China。
