Correlation between lattice distortion and friction stress in Ni-based equiatomic alloys

• Published in: Intermetallics Vol. 86; pp. 45 - 50
• Main Authors: Zhao, Y.Y., Nieh, T.G.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-07-2017
• Subjects: Dislocation core width; High-entropy alloys; Lattice distortion; Lattice friction stress; Yield strength; High-entropy alloys; Lattice friction stress; Yield strength; Lattice distortion; Dislocation core width
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2017.03.011

Many recent efforts have been made to apply traditional theories for solid solution strengthening to explain the strength increase in concentrated equiatomic alloys (or high-entropy alloys), but always faced the challenge of differentiating solvent from solute atoms. In this report, we conducted a systematical analysis of Ni-based equiatomic alloys with a face-centered cubic structure and found that the lattice distortion in this alloy system could be simply described by the parameter of atomic size mismatch. It was found that lattice friction stresses of these alloys were well correlated with the lattice distortion. Dislocation core width in this Ni-based alloy system was also estimated and compared with that in the pure nickel. The intrinsically high strength in high-entropy alloys was probably resulted from a high lattice friction stress.
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•Lattice distortion in high-entropy alloys (HEAs) can be simply defined as the lattice mismatch.•The lattice friction stress of Ni-based equiatomic alloys is linearly proportional to the lattice distortion.•High lattice friction stress in HEAs may be attributed to the wiggled dislocation line and a smaller dislocation core.•Dislocation core width in fcc-Ni-based equiatomic alloys is estimated to be ∼1.3b, lower than that in pure fcc-Ni.