TY - JOUR
T1 - Designing cobalt-free face-centered cubic high-entropy alloys
T2 - A strategy using d-orbital energy level
AU - Li, Yulin
AU - Olejarz, Artur
AU - Kurpaska, Łukasz
AU - Lu, Eryang
AU - Alava, Mikko J.
AU - Kim, Hyoung Seop
AU - Huo, Wenyi
PY - 2024/11
Y1 - 2024/11
N2 - High-entropy alloys (HEAs) are promising materials for high-temperature structural applications such as nuclear reactors due to their outstanding mechanical properties and thermal stability. Instead of the trial-and-error method, it is efficient to design and prepare single-phase face-centered cubic (FCC) structured HEAs using semi-empirical phase formation rules. However, almost all of phase formation rules were proposed without taking into account the cobalt-free situation. The HEAs containing cobalt are unsuitable for nuclear applications because of the long-term activation of cobalt. Here, six parameters, d-orbital energy level, valance electron concentration, entropy of mixing, enthalpy of mixing, atom size differences, and parameter of the entropy of mixing (Ω) were calculated to determine the solid solution phase, especially the FCC phase formation rules in cobalt-free HEAs. HEAs of 4 components were arc melted to verify the newly developed phase formation rules. The nanomechanical properties of produced HEAs were evaluated using nanoindentation. Among the six parameters, the d-orbital energy level and valance electron concentration are the critical factors that determine the FCC phase stability in cobalt-free alloys. Interestingly, the d-orbital energy level can be alone used as a benchmark for developing mechanical properties.
AB - High-entropy alloys (HEAs) are promising materials for high-temperature structural applications such as nuclear reactors due to their outstanding mechanical properties and thermal stability. Instead of the trial-and-error method, it is efficient to design and prepare single-phase face-centered cubic (FCC) structured HEAs using semi-empirical phase formation rules. However, almost all of phase formation rules were proposed without taking into account the cobalt-free situation. The HEAs containing cobalt are unsuitable for nuclear applications because of the long-term activation of cobalt. Here, six parameters, d-orbital energy level, valance electron concentration, entropy of mixing, enthalpy of mixing, atom size differences, and parameter of the entropy of mixing (Ω) were calculated to determine the solid solution phase, especially the FCC phase formation rules in cobalt-free HEAs. HEAs of 4 components were arc melted to verify the newly developed phase formation rules. The nanomechanical properties of produced HEAs were evaluated using nanoindentation. Among the six parameters, the d-orbital energy level and valance electron concentration are the critical factors that determine the FCC phase stability in cobalt-free alloys. Interestingly, the d-orbital energy level can be alone used as a benchmark for developing mechanical properties.
KW - Cobalt-free
KW - D-orbital energy level
KW - High-entropy alloys
KW - Phase formation
KW - Radiation resistant
KW - 114 Physical sciences
U2 - 10.1016/j.ijrmhm.2024.106834
DO - 10.1016/j.ijrmhm.2024.106834
M3 - Article
AN - SCOPUS:85201484010
SN - 0263-4368
VL - 124
JO - International Journal of Refractory Metals and Hard Materials
JF - International Journal of Refractory Metals and Hard Materials
M1 - 106834
ER -