High Performance NbMoTa-Al₂O₃ Multilayer Composite Structure Manufacturing by Laser Directed Energy Deposition

The conventional method of preparing metal-ceramic composite structures causes delamination and cracking defects due to differences in the composite structures' properties, such as the coefficient of thermal expansion between metal and ceramic materials. Laser-directed energy deposition (LDED) technology has a unique advantage in that the composition of the materials can be changed during the forming process. This technique can overcome existing problems by forming composite structures. In this study, a multilayer composite structure was prepared using LDED technology, and different materials were deposited with their own appropriate process parameters. A layer of Al₂O₃ ceramic was deposited first, and then three layers of a NbMoTa multi-principal element alloy (MPEA) were deposited as a single composite structural unit. A specimen of the NbMoTa-Al₂O₃ multilayer composite structure, composed of multiple composite structural units, was formed on the upper surface of a φ20 mm × 60 mm cylinder. The wear resistance was improved by 55% compared to the NbMoTa. The resistivity was 1.55 × 10^-5 Ω × m in the parallel forming direction and 1.29 × 10^-7 Ω × m in the vertical forming direction. A new, electrically anisotropic material was successfully obtained, and this study provides experimental methods and data for the preparation of smart materials and new sensors.