Dynamic mechanical properties, deformation and damage mechanisms of eutectic high-entropy alloy AlCoCrFeNi2.1 under plate impact. (20th January 2023)

• Record Type: Journal Article
• Authors: Zhao, S.P.; Feng, Z.D.; Li, L.X.; Zhao, X.J.; Lu, L.; Chen, S.; Zhang, N.B.; Cai, Y.; Luo, S.N.
• Is Part Of: Journal of materials science & technology. Volume 134(2023)
• Page Start: 178
• Page End: 188
• Publication Date: 2023-01-20
• Subjects: High-entropy alloy Hugoniot Spall damage Microstructure; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2022.05.060
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: Both L12 and B2 phases remain ordered at 12 GPa. The accurate hugoniot equation of state of AlCoCrFeNi2.1 is obtained. Nanotwins are observed in L12 phase. Both ductile and brittle fracture modes are observed. Abstract: Shock compression and spallation of a eutectic high-entropy alloy (HEA) AlCoCrFeNi2 . 1 with lamellar structure are investigated via plate impact loading with free-surface velocity measurements. The as-cast and postmortem samples are characterized with transmission electron microscopy, electron back-scatter diffraction and scanning electron microscopy. An accurate Hugoniot equation of state is determined. After shock compression to ∼ 12 GPa, both the L12 and B2 phases retain their ordered structures. Dense dislocations in the {111} slip planes, stacking faults and deformation twins are found in the L12 phase, along with fewer dislocations in the {110} slip bands in the B2 phase. Shock-induced deformation twinning within the L12 phase of this HEA is observed as a new deformation mechanism under various loading conditions. For spallation, both ductile and brittle damage modes are observed. The micro voids and cracks prefer to nucleate at the phase boundaries chiefly, then in the B2 phase. Under similar shock stress, the spall strength of AlCoCrFeNi2 . 1 HEA is about 40% higher than those of other reported dual-phase HEAs due to the high stability of its semi-coherent phase boundaries. Graphical abstract: Image, graphical abstract