TY - JOUR

T1 - Evolutionary design of strong and stable high entropy alloys using multi-objective optimisation based on physical models, statistics and thermodynamics

AU - Menou, Edern

AU - Toda-Caraballo, Isaac

AU - Rivera-Díaz-del-Castillo, Pedro Eduardo Jose

AU - Pineau, Camille

AU - Bertrand, Emmanuel

AU - Ramstein, Gérard

AU - Tancret, Franck

PY - 2018/4/5

Y1 - 2018/4/5

N2 - A new integrated computational HEA design strategy is proposed. It combines a multi-objective genetic algorithm with (i) statistical criteria to guide the formation of a single phase, supplemented by computational thermodynamics (Thermo-Calc) and (ii) models for the estimation of alloy yield stress via solid solution hardening, to be maximised, and alloy density, to be minimised. This strategy is applied to the design of face-centered-cubic (FCC) HEAs and yields several thousands of new alloys. An alloy featuring an interesting combination of predicted stability, strength and density, Al10Co17Fe34Mo5Ni34 (at%), is chosen among them, fabricated by vacuum arc melting and experimentally tested. The microstructure of this new HEA consists in a single FCC solid solution, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS) mapping. With a density of 7.95 g⋅cm- 3, a Vickers hardness of 1.78 GPa, a yield stress of 215 MPa and an ultimate tensile strength of 665 MPa in the annealed state, its properties surpass those of existing FCC HEAs of comparable density.

AB - A new integrated computational HEA design strategy is proposed. It combines a multi-objective genetic algorithm with (i) statistical criteria to guide the formation of a single phase, supplemented by computational thermodynamics (Thermo-Calc) and (ii) models for the estimation of alloy yield stress via solid solution hardening, to be maximised, and alloy density, to be minimised. This strategy is applied to the design of face-centered-cubic (FCC) HEAs and yields several thousands of new alloys. An alloy featuring an interesting combination of predicted stability, strength and density, Al10Co17Fe34Mo5Ni34 (at%), is chosen among them, fabricated by vacuum arc melting and experimentally tested. The microstructure of this new HEA consists in a single FCC solid solution, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS) mapping. With a density of 7.95 g⋅cm- 3, a Vickers hardness of 1.78 GPa, a yield stress of 215 MPa and an ultimate tensile strength of 665 MPa in the annealed state, its properties surpass those of existing FCC HEAs of comparable density.

KW - AlCoFeMoNi

KW - CALPHAD

KW - Gaussian process

KW - NSGA-II

U2 - 10.1016/j.matdes.2018.01.045

DO - 10.1016/j.matdes.2018.01.045

M3 - Journal article

AN - SCOPUS:85041712156

VL - 143

SP - 185

EP - 195

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

ER -