TY - JOUR
T1 - Adiabatic shear localization induced by dynamic recrystallization in an FCC high entropy alloy
AU - Jiang, Kun
AU - Li, Jianguo
AU - Kan, Xiukai
AU - Zhao, Feng
AU - Hou, Bing
AU - Wei, Qiuming
AU - Suo, Tao
N1 - Publisher Copyright:
© 2023
PY - 2023/3
Y1 - 2023/3
N2 - Due to their strong strain hardening, face-centered cubic (FCC) high/medium entropy alloys (H/MEAs) have remarkable resistance to shear localization even under forced dynamic shear. In this work we investigated the dynamic mechanical behavior of an FCC Al0.1CoCrFeNi HEA via a series of split Hopkinson pressure bar (SHPB) experiments at 77 K and room temperature. This HEA exhibited very strong strain hardening capacity, remarkable strain rate sensitivity and moderate temperature dependence. Such a combination of mechanical properties should be strongly unfavorable for adiabatic shear bands (ASBs). However, its dynamic compressive failure at 77 K was found to be caused by crack propagation within the primary ASBs along the directions of maximum shear stress. Detailed examination of the specimens using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) revealed convincing microstructural evidences for massive dynamic recrystallization (DRX) prior to ASB. We suggested that the expansion and coalescence of these DRX softened regions served as the root cause for the occurrence of ASBs and the final catastrophic fracture of specimens. The severe local shear flow, substantial adiabatic temperature rise and extremely fast quenching within the ASB resulted in ultrafine grains therein. Our results and analyses provided a plausible understanding of the formation mechanisms of ASBs in the FCC HEA under impact loading.
AB - Due to their strong strain hardening, face-centered cubic (FCC) high/medium entropy alloys (H/MEAs) have remarkable resistance to shear localization even under forced dynamic shear. In this work we investigated the dynamic mechanical behavior of an FCC Al0.1CoCrFeNi HEA via a series of split Hopkinson pressure bar (SHPB) experiments at 77 K and room temperature. This HEA exhibited very strong strain hardening capacity, remarkable strain rate sensitivity and moderate temperature dependence. Such a combination of mechanical properties should be strongly unfavorable for adiabatic shear bands (ASBs). However, its dynamic compressive failure at 77 K was found to be caused by crack propagation within the primary ASBs along the directions of maximum shear stress. Detailed examination of the specimens using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) revealed convincing microstructural evidences for massive dynamic recrystallization (DRX) prior to ASB. We suggested that the expansion and coalescence of these DRX softened regions served as the root cause for the occurrence of ASBs and the final catastrophic fracture of specimens. The severe local shear flow, substantial adiabatic temperature rise and extremely fast quenching within the ASB resulted in ultrafine grains therein. Our results and analyses provided a plausible understanding of the formation mechanisms of ASBs in the FCC HEA under impact loading.
KW - Adiabatic shear band
KW - Dynamic recrystallization
KW - Dynamic uniaxial compression
KW - High entropy alloys
UR - http://www.scopus.com/inward/record.url?scp=85149437787&partnerID=8YFLogxK
U2 - 10.1016/j.ijplas.2023.103550
DO - 10.1016/j.ijplas.2023.103550
M3 - 文章
AN - SCOPUS:85149437787
SN - 0749-6419
VL - 162
JO - International Journal of Plasticity
JF - International Journal of Plasticity
M1 - 103550
ER -