Understanding of surface segregation of Cu and Zn on nano Si precipitates to the mechanical property improvement of high pressure die casting Al9Si3CuFe alloy

To understand Si precipitation and its influence on mechanical property improvement in high pressure die casting (HPDC) Al9Si3CuFe alloy under direct ageing heat treatment, the precipitates containing in-situ MgAl2O4 particles is analyzed via atomic-resolution scanning transmission electron microscopy. It shown that lath-like form an average size of 50 nm length, a good orientation relationship {010}<001>Al//{111}<01–1>Si observed between precipitate matrix. Interestingly, Cu Zn are to segregate onto Si/Al interface, which has coarsening resisting effect growth. The presence these main factor contributing further properties alloy, results increase 70 MPa yield strength compared without precipitates.