Lattice strain framework for plastic deformation in complex concentrated alloys including high entropy alloys

Abstract

Alloys involving multiple solutes where the concentrations are such that it becomes difficult to identify a “solvent”, such as the so called “high entropy alloys”, have the potential for interesting combinations of properties. A key question relates to the fundamental mechanisms of plastic deformation in these alloys. A simple lattice strain framework is proposed for complex concentrated alloys to address the energetics and kinetics of dislocations and twins. It is argued that the lattice strain in highly concentrated alloys raises the base energy of the crystal and thereby reduces the additional energy required to nucleate dislocations and twins. However, the kinetics of dislocation motion are dampened by the lattice strain and local energy variations. This is reflected in lower values of activation volume. This framework can be used to design non-equiatomic high entropy alloy matrixes that enhance the properties achieved thus far.

Keywords:

• Strengthening mechanisms
• Twinning
• Dislocation kinetics
• Alloy design
• Complex concentrated alloys
• Solid solution strengthening
• Plastic deformation
• Dispersion strengthening