Fig. 4

Composition of density standards made of pure aluminum (Alu) (A), aluminum alloy (duralumin, Dur) (B), cuprum alloy (Cup) (C), iron–nickel alloy (IrNi) (D), and iron–silicon alloy (IrSi) (E) evaluated under a scanning electron microscope (SEM). Subfigures show the macroscopic sample (Smp), microscopic sample (Sem_SED), intensity versus energy chart, as well as mass percentage (Mass%) and atomic percentage (Atom%) corresponding to elements composition