Additive manufacturing of high-strength and ductile high entropy alloy CoCrFeNiW0.2 composites via laser powder bed fusion and post-annealing

• Published in: Journal of alloys and compounds 2022-06, Vol.906, p.164288, Article 164288
• Main Authors: Ng, Chee Koon, Bai, Kewu, Wuu, Delvin, Lau, Kwang Boon, Lee, Jing Jun, Cheong, Augustine Kok Heng, Wei, Fengxia, Cheng, Baisong, Wang, Pei, Tan, Dennis Cheng Cheh, Zhang, Yong-Wei
• Format: Article
• Language: English
• Subjects: Annealing; Diffusion; Ductility; Grain boundaries; High entropy alloys; Laser processing; Materials engineering; Mechanical analysis; Metal matrix composites; Metals and alloys; Microstructure; Powder beds; Powder metallurgy; Solid solutions
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.164288

•CoCrFeNiW0.2 metal-matrix composites (MMC) fabricated via additive manufacturing.•MMC exhibits comparable tensile properties to casted high entropy alloys with higher W.•Diffusion between unmelted W and metal-matrix investigated by thermo-kinetic simulations.•Combination of strength and ductility attributed by synergistic strengthening mechanisms.•Unique roles of W in the as-fabricated and post-annealed MMCs are explored. [Display omitted] A CoCrFeNiW0.2 metal-matrix composite (MMC) was fabricated by laser powder bed fusion (LPBF) and post-annealing, which exhibited comparable tensile ductility (44%) and yield strength (385 MPa) to as-casted CoCrFeNiW high entropy alloys with much higher W concentration. An Integrated Computational Materials Engineering (ICME) framework coupled with thermo-kinetic simulations was built to investigate the microstructure evolution and mechanical response of the as-fabricated and post-annealed MMCs. The combination of strength and ductility of the MMC can be attributed to the synergistic combination of dislocation, solid solution and grain boundary strengthening due to the multiple roles of W in the LPBF and post-annealing processes.