Microstructure-based alloy compression strengthening model of an equiatomic high-entropy alloy CoCrFeNiNb

High-entropy alloys within the scientific community was promoted due to their exceptionally high mechanical and physical properties, namely compression strength, toughness, plasticity, hardness, wear, corrosion resistance, and thermal stability. In the present study, an equiatomic CoCrFeNiNb HEA was prepared by a sequence of conventional induction melting, powder metallurgy, and compaction via spark plasma sintering. The as-cast HEA showed an ultimate compression strength (UCS) of ~1400 MPa. After sintering and compaction at 1273K the UCS increased considerably up to ~2400 MPa. After compaction at 1273K the fcc phase was characterized by a diffuse presence of nano-size twinning. Extensive TEM quantitative analyses were carried out to model the UCS by the most significant microstructure strengthening features. A quite good agreement between the microstructure-strengthening model and the experimental UCS was found