In 2010, Senkov et al. created the first refractory RHEA (“R-H-E-A”) kind of these systems, which themselves are based on another one of these systems described as “high-entropy.” One of these systems (15[1])can transform between different stress-induced phases when exposed to varying strain levels, thereby displaying pseudoelasticity. The identity of these systems, which often depends on whether one quantity for a constituent is 15% (15[1])larger than the other, can be (15[1])predicted via the (*) Hume-Rothery rules. Nitinol is an example of one of these systems (10[1])exhibiting “shape memory.” (-5[1])Whether a smaller (10[1])atom (10[1])replaces a larger atom’s (10[1])site or sits inside a lattice’s gap (-5[1])determines if these systems are substitutional or interstitial. Amalgams (10[1]-5[1])are one (-5[1])of these systems mainly (10[1])made of mercury. For 10 points, name these solid solutions composed of two or more different metals. ■END■ (10[5])