TY  - JOUR
AU  - Zhang, Haifeng
AU  - Jia, Nan
AU  - Wang, Mingming
AU  - Zheng, Aiyun
AU  - Ji, Hongchao
TI  - Deformation mechanism differences of lamellar/core-shell FCC/B2 composites: atomic simulation study
JO  - Microstructures
PY  - 2026
VL  - 6
IS  - 6
SP  - 
EP  - 20260133
SN  - ISSN 2770-2995 (Online)
AB  - <p>AlCoCrFeNi eutectic multi-principal element alloys exhibit remarkable application potential owing to their inherent heterostructures and outstanding mechanical properties. Their mechanical behaviors are governed by the synergistic deformation of non-uniformly distributed face-centered cubic (FCC) and B2 phases. Clarifying the synergistic deformation mechanisms of FCC/B2 composites is therefore essential. Herein, molecular dynamics simulations are employed to investigate the mechanical behaviors and deformation mechanisms of FCC/B2 composites with lamellar and core-shell structures in AlCoCrFeNi<sub>2.1</sub>, Fe<sub>20</sub>Co<sub>20</sub>Ni<sub>41</sub>Al<sub>19</sub> (at.%), and Ni + NiAl alloys. The results demonstrate that the elastic modulus of all composites is nearly identical during the elastic deformation stage. Upon yielding, lamellar samples display a higher yield stress yet poorer plasticity compared with the core-shell samples. The B2-core structure exhibits excellent plastic deformation capability, which originates from the coordinated activation of abundant dislocations, twins, and stacking faults suppressing void expansion. For lamellar samples, decreasing elemental diversity enhances yield strength by stabilizing heterogeneous interfaces and elevating the stacking fault energy of the FCC phase. Nevertheless, the scarcity of deformation systems promotes defect accumulation and accelerated void growth along phase boundaries, thereby degrading the material ductility. Differently, the yield strength of the core-shell composite is less sensitive to element composition. Compared with multi-principal element alloys, pure Ni in the Ni + NiAl model exhibits higher stacking fault energy and milder lattice distortion, which hinders the activation of Shockley partial dislocations and reduces dislocation storage capacity, thereby leading to inferior plasticity. The present findings provide theoretical guidance for developing high-strength-ductility alloys with non-uniform structures.</p>
KW  - Non-uniform structure
KW  - eutectic multi-principal element alloy
KW  - micromechanical behavior
KW  - plastic deformation mechanism
KW  - atomic simulation
DO  - 10.20517/microstructures.2026.156
UR  - https://dx.doi.org/10.20517/microstructures.2026.156