Microstructure refinement and wear resistance enhancement of cost-effective Fe 50 2x Mn 30 Co 10 Cr 10 Ni x Cu x (x = 0, 5 at%) high-entropy alloys through cyclic closed-die forging process Majid Naseri a,* , Alena Myasnikova a , Omid Imantalab b,* , Davood Gholami c , Dmitry Mikhailov a , Mostafa Amra d , Nataliya Shaburova a , Aleksandr Orlov a , Seyedmehdi Hosseini e , Yong-Cheng Lin f , Ehsan Borhani g , Abdel-Hamid I. Mourad h,i , Evgeny Trofimov a a South Ural State University, 76 Lenin Av., Chelyabinsk 454080, Russia b Department of Materials Engineering, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran c School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, Iran d Padideh Sanat Ouj Co., Tehran, Iran e Brunel Centre for Advanced Solidification Technology (BCAST), Brunel University London, Uxbridge UB8 3PH, UK f School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China g Nanomaterials Department, Faculty of New Sciences and Technologies, Semnan University, Semnan, Iran h Mechanical and Aerospace Engineering Department, College of Engineering, United Arab Emirates University, Al-Ain 15551, United Arab Emirates i National Water and Energy Center, United Arab Emirates University, Al-Ain 15551, United Arab Emirates HIGHLIGHTS • Novel low-cost Fe 50 2x Mn 30 Co 10 Cr 10 Ni x Cu x (x = 0, 5 at%) HEAs were subjected to CCDF. • The newly produced HEAs were single-phase FCC solid-solution bulk metallic materials. • CCDF significantly improved the microhardness and wear resistance of the HEAs. • Plastic deformation and adhesive wear were significantly reduced in the CCDF-processed alloys. • CCDF is suggested as an effective approach for developing nanostructured HEAs. A R T I C L E INFO Keywords: High-entropy alloy Cyclic closed-die forging Microstructure evolution Hardness Wear resistance ABSTRACT Novel low-cost Fe 50 2x Mn 30 Co 10 Cr 10 Ni x Cu x (x = 0, 5 at%) high-entropy alloys (HEAs) were produced by vacuum melting and then processed by the cyclic closed-die forging (CCDF) process. It was found that both the as- homogenized and CCDF-processed specimens primarily consisted of a single face-centered cubic (FCC) struc- ture, and the severe plastic strain through CCDF did not result in phase transformations. The microstructure of the CCDF-processed Fe 50 Mn 30 Co 10 Cr 10 alloy after the sixth pass demonstrated a uniform structure with ultrafine grains measuring 285 nm in size, whereas for the CCDF-processed Fe 40 Mn 30 Co 10 Cr 10 Ni 5 Cu 5 alloy, the grain size was 135 nm, with a relatively uniform distribution. The CCDF-processed Fe 50 Mn 30 Co 10 Cr 10 and especially the Fe 40 Mn 30 Co 10 Cr 10 Ni 5 Cu 5 alloy exhibited significantly higher microhardness compared to the as-homogenized state, with microhardness values being 2.42 and 2.72 times higher, respectively. Furthermore, the wear test results indicated that the CCDF processing effectively increased the wear resistance of the alloys, which was attributed to the changes in morphology and distribution of as-cast dendrites, along with the grain refinement of the matrix phase during CCDF. The CCDF-processed Fe 40 Mn 30 Co 10 Cr 10 Ni 5 Cu 5 alloy exhibited the lowest wear rate, i.e., (1.2 ± 0.2) × 10 –5 mm 3 .N  1 .m  1 , whereas that for the Fe 50 Mn 30 Co 10 Cr 10 alloy was (2.4 ± 0.1) × 10 –5 mm 3 .N  1 .m  1 . Analysis of wear surfaces indicated that the wear mechanisms of the as-homogenized HEAs were adhesive wear and abrasive wear with some delamination, while plastic deformation and adhesive wear were significantly reduced in the CCDF-processed specimens, especially in the Fe 40 Mn 30 Co 10 Cr 10 Ni 5 Cu 5 alloy. These * Corresponding authors. E-mail addresses: naserim@susu.ru, majid_na3ri@yahoo.com (M. Naseri), o.imantalab@basu.ac.ir (O. Imantalab). Contents lists available at ScienceDirect Colloids and Surfaces A: Physicochemical and Engineering Aspects journal homepage: www.elsevier.com/locate/colsurfa https://doi.org/10.1016/j.colsurfa.2024.135345 Received 28 July 2024; Received in revised form 29 August 2024; Accepted 9 September 2024 Colloids and Surfaces A: Physicochemical and Engineering Aspects 703 (2024) 135345 Available online 10 September 2024 0927-7757/© 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.