TY - JOUR
T1 - Simultaneous enhancement of strength and resistance to shear localization in CrCoNi medium entropy alloys by Al alloying under dynamic loading
AU - Zhang, Linbing
AU - Li, Zezhou
AU - He, Jianye
AU - Wang, Jun
AU - Yu, Yuchen
AU - He, Jingyao
AU - Fu, Ao
AU - Zhang, Fan
AU - Wang, Lin
AU - Cheng, Xingwang
N1 - Publisher Copyright:
© 2026
PY - 2026/2
Y1 - 2026/2
N2 - CrCoNi-based face-centered-cubic(fcc) medium- or high-entropy alloys with low stacking-faults energies exhibit extraordinary fracture toughness ranging from cryogenic temperature to room temperature. Various deformation mechanisms such as dislocation slip and deformation twinning enable them to absorb considerable deformation energy and resist crack propagation. However, their yield strength is not high enough for structural applications. This study systematically designed CrCoNi-based medium-entropy alloys (MEAs) through supplementing aluminum (Al) content (0–12 at. %). Primary objectives were to enhance the yield strength and analyze dynamic deformation mechanisms and adiabatic shear localization for these CrCoNi-based MEAs. At ∼6000 s−1, yield strength increased from 639 MPa for the (CrCoNi)97Al3 MEA to 1224 MPa for the (CrCoNi)88Al12 MEA, primarily due to the strengthening of secondary B2 phase. However, the B2 phase in (CrCoNi)88Al12 MEA accelerates dynamic recrystallization, thereby promoting the occurrence of adiabatic shear localization. The (CrCoNi)92.5Al7.5 MEA exhibited significant resistance to shear localization, which was attributed to the presence of numerous deformation mechanisms, including dislocation glide, stacking-faults, Lomer-Contrell locks, deformation twins, and fcc to hexagonal close-packed (hcp) phase transformation. This gave rise to absorbed strain energy of 714 MJ/m3 in (CrCoNi)92.5Al7.5 MEA. This study establishes a reliable theoretical basis for the engineering deployment of CrCoNi MEAs as lightweight protective materials.
AB - CrCoNi-based face-centered-cubic(fcc) medium- or high-entropy alloys with low stacking-faults energies exhibit extraordinary fracture toughness ranging from cryogenic temperature to room temperature. Various deformation mechanisms such as dislocation slip and deformation twinning enable them to absorb considerable deformation energy and resist crack propagation. However, their yield strength is not high enough for structural applications. This study systematically designed CrCoNi-based medium-entropy alloys (MEAs) through supplementing aluminum (Al) content (0–12 at. %). Primary objectives were to enhance the yield strength and analyze dynamic deformation mechanisms and adiabatic shear localization for these CrCoNi-based MEAs. At ∼6000 s−1, yield strength increased from 639 MPa for the (CrCoNi)97Al3 MEA to 1224 MPa for the (CrCoNi)88Al12 MEA, primarily due to the strengthening of secondary B2 phase. However, the B2 phase in (CrCoNi)88Al12 MEA accelerates dynamic recrystallization, thereby promoting the occurrence of adiabatic shear localization. The (CrCoNi)92.5Al7.5 MEA exhibited significant resistance to shear localization, which was attributed to the presence of numerous deformation mechanisms, including dislocation glide, stacking-faults, Lomer-Contrell locks, deformation twins, and fcc to hexagonal close-packed (hcp) phase transformation. This gave rise to absorbed strain energy of 714 MJ/m3 in (CrCoNi)92.5Al7.5 MEA. This study establishes a reliable theoretical basis for the engineering deployment of CrCoNi MEAs as lightweight protective materials.
KW - (CrCoNi)Al MEAs
KW - Adiabatic shear localization
KW - Dynamic deformation
UR - https://www.scopus.com/pages/publications/105027390582
U2 - 10.1016/j.matchar.2026.116017
DO - 10.1016/j.matchar.2026.116017
M3 - 文章
AN - SCOPUS:105027390582
SN - 1044-5803
VL - 232
JO - Materials Characterization
JF - Materials Characterization
M1 - 116017
ER -