Simultaneously enhanced strength-ductility of AlCoCrFeNi2.1 eutectic high-entropy alloy via additive manufacturing

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2022-01, Vol.830, p.142327, Article 142327
• Main Authors: Huang, Liufei, Sun, Yaoning, Chen, Na, Luan, Hengwei, Le, Guomin, Liu, Xue, Ji, Yaqi, Lu, Yiping, Liaw, Peter K., Yang, Xiaoshan, Zhou, Yuzhao, Li, Jinfeng
• Format: Article
• Language: English
• Subjects: Cooling rate; Ductility; Eutectic alloys; Eutectic high-entropy alloy; Eutectics; High entropy alloys; Homogeneous structure; Laser deposition; Laser metal deposition; Mechanical properties; Mechanical property; Microstructure; Strain hardening; Tensile properties; Tensile strength
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2021.142327

The negative effects of thermal cycles in the process of additive manufacture present a challenge for the control of microstructure so as to fabricate the products with improved properties compared with conventional casting technique. In this work, AlCoCrFeNi2.1 eutectic high-entropy alloy (EHEA) was prepared by laser metal deposition (LMD). Compared with conventionally cast EHEA samples, the LMD-fabricated EHEA samples showed significantly enhanced tensile strength (by 19.7%) and increased tensile ductility (by 56.4%). Such enhancement in tensile properties was attributed to the refinement of the uniformly distributed eutectic-structure, which improved the strain hardening/dislocation accumulation capability of the EHEA. The present work provides a new strategy to utilize both the high cooling rates of LMD and the eutectic-structure characteristics for forming refined homogeneous structures and thus achieving superior mechanical properties to those prepared by traditional processing techniques.