Er-containing microalloyed aluminum alloys: a review

Microalloying has been an important method in aluminum alloy development for decades. Large number of papers have shown that the addition of trace element Erbium (Er) can effectively improve the comprehensive properties of aluminum alloys. Similar with the trace element Scandium (Sc), addition of trace element Er in aluminum alloys could form nano-sized L1₂-ordered Al₃Er precipitates, which was coherent with the Al matrix. However, the dispersion precipitation strengthening effect of Al₃Er was more significant than that of Al₃Sc, at the same atomic content. In the case of the addition of both Er and Zr, core–shell-structured Al₃(Er, Zr) precipitates formed instead of Al₃Er precipitates. Those thermally-stable nanosized precipitates could significantly refine the grain size, retard the recrystallization, improve the mechanical properties and corrosion resistance. This paper reviewed several typical Er-containing microalloyed commercial aluminum alloys, like 2xxx (Al–Cu) alloys, 4xxx (Al–Si) alloys, 5xxx (Al–Mg) alloys, 7xxx (Al–Zn–Mg–Cu) alloys, as well as selective laser melting aluminum alloys.