During rheo-high pressure die casting (R-HPDC) of Al‑Zn-Mg-Cu alloys a coarse eutectic phase is formed. This eutectic phase is difficult to take into solution because of its size and it would require longer solution heat treatment times. The objective of this work was to determine the time for sufficient dissolution of the eutectic phase in this Al-Zn-Mg-Cu alloy. Solution heat treatment was carried out at 473°C for various time periods and the samples were quenched in water. The samples were then artificially aged at 120°C for 24 hrs. A component of the eutectic was observed to have dissolved and another component transformed to new intermetallic phases for all solution heat treatment times at 473°C.