Enhanced dynamic-mechanical property and microstructural mechanism of a FeCoNiCrMo0.2 high-entropy alloy fabricated using powder bed fusion

• DOI: 10.1016/j.jmrt.2024.03.113
• Publication Date: 2024-03-19T16:59:50Z
• Authors: Wenshu Li; Ruoyu Liu; Shaohong Wei; Yiyu Huang; Qi Wu; Ao Fu; Yubin Ke; Peter K. Liaw; Bin Liu; Bingfeng Wang
• Keywords: High-Entropy Alloys; Volume fraction; Deformation mechanism

Powder bed fusion (PBF), along with subsequent heat treatment, plays a crucial role in enhancing the impact toughness of FeCoNiCrMo0.2 high-entropy alloys (HEAs) and expanding their potential applications field for high-speed deformation. In this study, dynamic-mechanical properties microstructure as-built PBF–FeCoNiCrMo0.2 HEAs quenched heated at 600–750 °C 8 h were investigated. As heating temperature increases, columnar grains cellular structures undergo coarsening dislocation density gradually decreases. Moreover, higher temperatures facilitate precipitation Mo-rich second phases. This occurrence can be primarily attributed to segregation Mo boundaries specimens. Consequently, specimens, μ phases are predominantly distributed structures. Q700 specimen (heated 700 8h), size volume fraction measured 63.4 nm 3.59%, respectively. Additionally, under same condition, specimens also exhibited relatively slight increase The energy absorption, dynamic yield strength, compressive strength found 210.1 MJ/m3, 1066 MPa, 1649 MPa strain rate 1840 s−1. These values represent dramatic improvement 38.1%, 52.7%, 14.7% comparison those Under deformation, presence significant impeding movement dislocations by acting as pinning agent structures, thereby strength. Simultaneously, significantly elongated form deformation bands coordinate leading good absorption. combination, synergistic strengthening toughening effect contribute remarkable PBF-HEAs.