Adhesion with Aluminum for Material Surfaces Additively Manufactured by Directed Energy Deposition

The adhesion of aluminum to molds or tools is common during the production of aluminum alloy products for vehicle light weighting. It reduces the productivity and quality, and thus, it needs to be prevented. This study attempted to use directed energy deposition (DED) to deposit a heterogeneous material on the surface of a mold material to prevent the aluminum adhesion. The powders used in the heterogeneous material deposition included the Fe-based alloys D2 and H13, Ni-based alloy Inconel718, and Co-based alloy Stellite21. Immersion tests and wear tests were performed to test the deposits’ reactivity with aluminum. After the immersion of deposited samples into melted aluminum, the smallest amount of adhesion was observed on the D2 surface. The H13-deposited zone had the highest value of hardness. However, the hardness of the deposited surface did not display a close relationship with aluminum adhesion. In addition, the H13- and Stellite21-deposited zones displayed high thermal conductivity compared with the other two specimens. The microimages and elemental analyses revealed that the adhesion was formed owing to metallurgical fusion. During the wear tests, the temperature increased owing to the friction between the aluminum pins and deposited specimens. Stellite21 and H13 produced a smaller temperature increase than Inconel718 and D2. From the wear test, it was observed that the aluminum pin material adhered to the wear specimen surface for the D2-, H13- and Inconel718-deposited specimens. Thick aluminum adhesion layers were formed in the case of the D2 and Inconel718 specimens. Nevertheless, aluminum adhesion could not be observed on the Stellite21 specimen’s surface, whereas typical wear scars caused by wearing were apparent. It can be concluded that adhesion with aluminum varies according to the alloy elements contained in the metal alloy as well as the thermal conductivity of the deposited materials.