Cartoon of the AlCoCrFeNi high entropy alloy (HEA) with body-centered cubic (BCC) lattice. HEAs also come in face-centered cubic (FCC) and (less frequently) hexagonal close packing (HCP). BCC HEAs typically have high yield strength and low ductility, vice versa for FCC HEAs. Wiki article.
\documentclass[tikz]{standalone}
\pgfmathdeclarerandomlist{colors}{{red!80}{teal}{blue!80}{orange}{blue!20}}
\begin{document}
\begin{tikzpicture}
\foreach \i in {1,...,12} {
\foreach \j in {1,...,4} {
\foreach \k in {1,...,4} {
\pgfmathrandomitem{\randColor}{colors}
\shade[ball color=\randColor] (-\i+0.3*\j, -0.2*\j+1.2*\k) circle(0.3);
}
\foreach \k in {1,...,3} {
\pgfmathrandomitem{\randColor}{colors}
\shade[ball color=\randColor] (-\i+0.5+0.3*\j, -0.2*\j+1.2*\k+0.6) circle(0.3);
}
}
}
\foreach \el/\color [count=\n] in {Al/red!80, Co/blue!80, Cr/teal, Fe/orange, Ni/blue!20} {
\shade[ball color=\color] (2, 5.5-\n) circle(0.3) node[right=1em] {\el};
}
\end{tikzpicture}
\end{document}