Reaching unconventionally large Hall-Petch coefficients in face-centered cubic high-entropy alloys

作者：Jiaxiang Li, Kenta Yamanaka, Yongjie Zhang, Tadashi Furuhara, Guoqin Cao, Junhua Hu, Akihiko Chiba · 发表于：Materials Research Letters · 年份：2024 · DOI：10.1080/21663831.2024.2337211 · 被引用次数：29 · 研究领域：High Entropy Alloys Studies、Additive Manufacturing Materials and Processes、High-Temperature Coating Behaviors

The Hall-Petch strengthening coefficient of face-centered cubic alloys has the potential to increase. Herein, we experimentally determined an unconventionally large Hall-Petch coefficient equal to 1100 MPa·µm1/2 and a large lattice friction stress for novel Co0.95Cr0.8Fe0.25Ni1.8Mo0.475 high-entropy alloys (Mo0.475 HEAs). Detailed microstructural characterizations showed Mo segregation at grain boundaries (GBs) and no apparent nano-clustering in the matrix. With the increased Mo content, Mo segregating at GBs is an unexpected outcome. The unconventionally large Hall-Petch coefficient is ascribed to the newly generated effect due to Mo segregation at GBs, besides the factors in the grain interior, e.g. the increased solid-solution strengthening. This study is dedicated to enriching the diversity of Hall-Petch strengthening mechanisms for the development of high-strength materials.