Development of Thermal Treatments for Structural Parts Grafted in Aluminum Alloys

Abstract

In order to minimise the weight of vehicles, aluminium alloy parts produced by high pressure die casting are increasingly being used. However, due to the high injection speeds during the HPDC process, air is trapped in the liquid metal, causing porosity in the components. These gas porosities make it impossible to carry out heat treatments due to the blistering phenomenon. The work carried out therefore centres on the development of heat treatments (T5 and flash T6) on parts obtained by the vacuum-assisted HPDC process, using AlSi10MnMg and AlSi10Mg(Fe) alloys. The parts were characterised taking into account the occurrence of blistering, microstructure and mechanical properties achieved. In addition, the machinability of the AlSi10MnMg primary alloy was assessed using a PCD tool produced by additive manufacturing and compared with the one of AlSi9Cu3(Fe) conventional alloy. For all combinations of parameters used in the solution heat treatment, there were blisters in the components. With the T5 heat treatment there was no blistering and the mechanical strength increased. In terms of the machinability of the AlSi10MnMg primary alloy, it exhibits slightly higher surface roughness and lower cutting forces compared to the conventional AlSi9Cu3(Fe) injection alloy.