Fatigue behavior of modified aluminum alloys for casts used in e-mobility applications based on different casting processes and the use of recycled material

Kurzfassung

High pressure die casting of aluminum is a commonly used process to manufacture structural parts for vehicle bodies. The industrial shift towards e-mobility is an opportunity for new casted components, such as motor housings, gearboxes and their covers. To manufacture high quality casts with as little inner defects as possible, different casting processes have been developed and refined over the past years. Besides the casting processes, new aluminum alloys with high recycling content for e-mobility applications are in development to support the change of our world towards a CO2-neutral future. The new application field leads to changed or differently prioritized requirements. One important requirement for components of the powertrain of electric vehicles is fatigue strength. In the project “InDrutec-E”, funded by the German Federal Ministry for Economic Affairs and Energy, three known aluminum alloys for high pressure die casting of structural parts have been modified to fit the new requirements of e-mobility. They are investigated and compared with their base versions as well as with the reference alloy AlSi10Mg(Fe). These seven alloys have been casted by the following processes leading to a total series of 21 fatigue-cycle curves: - regular die casting - vacuum assisted die casting - Vacural® die casting, developed by the Oskar Frech GmbH The development of modified aluminum alloys can lead to a reduction of needed raw materials as well as smaller carbon footprint for die casted parts. In the project, a possible reduction of CO2-emissons by more than 40 % has been estimated when combining refined casting processes and newly developed Al alloys with high recycling content for structural casts. This lecture shows a selection of test results and highlights the difference in fatigue behavior between modified and base alloys. Also, the significant influence of the casting process on fatigue strength will be shown.