Corrosion Resistance of 3D-Printed and Conventional Die Steels in Contact with Molten Aluminum Alloys

This study investigates the corrosion resistance of maraging steel produced via additive manufacturing and conventional forging when exposed to molten aluminum alloys used in high-pressure die casting (HPDC). The H11 tool steel, typically used in such applications, was also studied for comparison. Static immersion tests were conducted in three different aluminum alloys for HPDC (AlSi7Mg, AlSi10Mg, AlSi10MgFe). SEM-EDS analysis revealed differences in the formation of intermetallic layers on the metallic surfaces, mainly depending on the material considered. The laser-power bed fused maraging steel, often used for conformal cooling inserts, exhibited the formation of a stable high Fe intermetallic layer without a liquid phase, contributing to superior corrosion resistance compared to the forged maraging steel. The H11 tool steel demonstrated the highest corrosion resistance, especially due to its composition free from Ni and the presence of Cr and Cr-carbide. Thermo-Calc equilibrium simulations identified the phases present in the intermetallic layers at the test temperature, highlighting the effects of different steel compositions on interfacial intermetallic layers. These findings underline the critical role of manufacturing processes and alloy composition on the performance of steels in contact with molten aluminum alloys, with implications for die casting applications.