|About this Abstract
||Materials Science & Technology 2020
||High Entropy Materials: Concentrated Solid Solution, Intermetallics, Ceramics, Functional Materials and Beyond
||High Entropy and Sluggish Diiffusion Effects in Co-Cr-Fe-Ni Based High Entropy Alloys
||Abhishek Mehta, Yongho Sohn
|On-Site Speaker (Planned)
High entropy and sluggish diffusion effects were investigated using solid-to-solid diffusion couple approach in Co-Cr-Fe-Ni base alloys. High entropy effect was examined in off-equiatomic compositions of Al-Co-Cr-Fe-Ni and Al-Co-Cr-Fe-Ni-Mn, generated by diffusion of Al and Ni in equiatomic CoCrFeNi and CoCrFeNiMn alloys. Thermodynamic stability (i.e. ΔH, –TΔS, and ΔG) of off-equiatomic compositions were compared to those of equiatomic compositions determined using pseudo-binary phase diagram. Due to the contribution from the enthalpy of mixing, a higher thermodynamic stability was determined for the off-equiatomic compositions than their equiatomic counterpart. Sluggish diffusion effect was examined by measuring interdiffusion and tracer diffusion coefficients in CoCrFeNi, CoCrFeNiMn, and Al0.25CoCrFeNi alloys. Comparison to solvent based traditional alloys suggest that diffusion is not always sluggish in high entropy alloys. Application of potential energy fluctuation model suggest that the larger fluctuation in lattice potential energy may not always result in sluggish diffusion kinetics.