Edge Dislocation and Grain Boundaries Effects on the Mechanical Properties in NiCoAl Medium Entropy Alloy

M Khan and ML Ali, ADVANCED ENGINEERING MATERIALS, 26 (2024).

DOI: 10.1002/adem.202400614

Medium-entropy alloys (MEAs) are becoming increasingly popular owing to their superior mechanical features. For the first time, using molecular dynamics (MD) simulations, investigation is done on how grain boundaries (GBs) and dislocations affect the mechanical properties of face-centered cubic (FCC) equiatomic NiCoAl$\textNiCoAl$ MEA. Lattice distortion, elastic constants and moduli, machinability index, Vickers hardness, and Kleinman parameters to explore how grain boundaries affect NiCoAl$\textNiCoAl$ MEA are analyzed. It tends to become more rigid based on the link between its elastic moduli and GBs. Interestingly, the analyses of Cauchy pressure, Poisson's, and Pugh's ratios all indicate the ductility of the studied MEA. The investigation of anisotropy factors indicates that NiCoAl$\textNiCoAl$ MEA exhibits anisotropy, which is reduced by the addition of GBs. Mechanical properties of the considered MEA, such as ductility, fracture toughness, and stability, are significantly influenced by the GBs. The obtained results show that studying these phenomena can help design structural nano-metal materials with superior mechanical properties, allowing them to be used in various applications. This study investigates how grain boundaries (GBs) and dislocations affect the mechanical properties of face-centered cubic (FCC) NiCoAl$\textNiCoAl$ medium-entropy alloy (MEA) using molecular dynamics simulations. GBs, particularly Sigma 5, enhance strength and hardness while influencing ductility, machinability, and anisotropy. The results highlight the significance of GBs in altering the mechanical behavior of NiCoAl$\textNiCoAl$ MEA for diverse applications.image (c) 2024 WILEY-VCH GmbH

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