On the characterisation of a hitherto unreported icosahedral quasicrystal phase in additively manufactured aluminium alloy AA7075

TL;DR

This study reports the discovery of a new icosahedral quasicrystal phase, called nu-phase, in additively manufactured AA7075 aluminum alloy, revealing novel microstructural features resulting from selective laser melting.

Contribution

First identification of a 5-fold symmetric icosahedral quasicrystal in additive manufacturing of AA7075 alloy, expanding understanding of its microstructure.

Findings

Discovery of nu-phase quasicrystal in AA7075.

Nu-phase contains Zn, Cu, and Mg.

Observed in as-manufactured, rapidly solidified state.

Abstract

Aluminium alloy AA7075 (Al-Zn-Mg-Cu) specimens were prepared using selective laser melting, also known as powder bed fusion additive manufacturing. In the as-manufactured state, which represents a locally rapidly solidified condition, the prevalence of a previously unreported icosahedral quasicrystal with 5-fold symmetry was observed. The icosahedral quasicrystal, which has been termed nu-phase, was comprised of Zn, Cu and Mg.