The role of alloy composition in the heat treatment of aluminium high pressure die castings


  • R.N. Lumley
  • R.G. O'Donnell
  • D.R. Gunasegaram
  • T. Kittel-Sherri
  • M. Gershenzon
  • A.C Yob
  • I.J. Polmear


High pressure die-cast (HPDC) aluminium components that respond to age hardening cannot normally be solution treated at high temperatures because the presence of internal porosity and entrapped gases leads to the formation of surface blisters. Parts may also become dimensionally unstable due to swelling. These factors that prevent heat treatment present significant limitations to the utilisation of HPDC components. Now it has been found that blistering and dimensional change can be avoided by using modified shorter solution treatment procedures which still allow strong responses to age hardening to be achieved with a wide range of Al-Si-(Cu/Mg) alloys. In the present paper, the roles of critical alloying elements are considered in both current commercial and experimental alloy compositions in this series. It is shown that values of 0.2% proof stress exceeding 400 MPa may be readily achieved by heat treating conventionally produced HPDC components.