Breakdown of Varvenne scaling in (AuNiPdPt)$_{1-x}$ Cu$_{x}$ high-entropy alloys

The compositional dependence of the yield strength σ$_{y}$ has been studied for a series of polycrystalline (AuNiPdPt)$_{1-x}$Cu$_{x}$ alloys by means of compression tests. σ$_{y}$ is found to decrease linearly with increasing Cu concentration. This behaviour is in contradiction to the generalised theory for solid solution strengthening in concentrated solid solutions provided by Varvenne et al. [1]. A breakdown of the scaling behaviour is found as σy should be non-linear and slightly increasing when modifying the composition from AuNiPdPt to AuCuNiPdPt.