Interaction kinetics between molten aluminium alloy Al99.7 and H11 tool steel with and without an AlCrN protective coating

Abstract

The tool used in die casting or hot forming is subjected to thermal and mechanical stress, resulting in damage and cracking due to thermal fatigue and melt flow. This reduces the profitability and efficiency of production, as the products may not meet the required dimensions and mechanical properties. Understanding the interaction between tool steel and molten aluminium alloy is critical to extending tool life. AlCrN protective coatings on tool surfaces can improve corrosion resistance, thermal fatigue and wear resistance.The present work was carried out to predict the effect of the AlCrN protective coating on the interaction kinetics between H11 tool steel and molten aluminium alloy Al99.7. The AlCrN protective coating on the H11 tool steel sample served its purpose and slowed down the interaction between the aluminium melt from Al99.7 and the H11 tool steel, as the DSC curve of the sample that had the AlCrN protective coating applied flattened out faster, indicating the cessation of dissolution in the material at all investigated temperatures. Measurements of the thicknesses of the interaction layers also confirmed these results, whereas the thickness of the composite layer was almost the same at both experimental temperatures, 670 °C and 700 °C, respectively, without an AlCrN protective coating; the temperature has no effect on this layer and the types of interaction layers did not differ from each other.

Keywords

• Tool steel–molten aluminium interaction
• AlCrN protective coating
• Interaction kinetics
• Interaction layer
• Temperature