Coarsening Behaviour of γ′ Precipitates in High Fe Containing Ni-Fe-Cr-Based Medium Entropy Alloy

Present work evaluates the coarsening kinetics of gamma ' precipitates in gamma-gamma '-based microstructure of a high Fe-containing low-density low-cost Ni-29.8Fe-11.1Cr-3.7Al (wt pct) medium entropy alloy. The experimentally estimated mean size of the gamma precipitates, during isothermal ageing of the alloy at 600 degrees C for the varying duration, agrees well with the theoretical prediction by considering interfacial energy of 10 mJ/m(2). This investigation suggests the sluggish coarsening kinetics with the diffusion of Cr across the gamma-gamma interface as the rate-controlling factor.