Combinatorial synthesis of AlNi alloys by low-pressure cold spray deposition and post-laser alloying process

Abstract

Aluminum-Nickel (AlNi) alloys are of great interest due to their exceptional high-temperature wear and corrosion resistance, making them valuable in transport, energy, and materials processing applications. However, challenges in the production and shaping of these alloys, particularly as thick coatings, remain significant. This study introduces an innovative method for the high-throughput synthesis of AlNi coatings, utilizing a two-step process: low-pressure cold spray deposition followed by laser surface alloying. The combination of these two techniques not only improves the synthesis process but also opens avenues for exploring new material compositions with specific application requirements. This approach holds significant potential for accelerating the development and optimization of advanced coatings and multiphase compounds in applications such as repair and additive manufacturing.

Aluminum and nickel powders were co-sprayed to create coatings with controlled compositions ranging from 50Al50Ni to 10Al90Ni (wt%). Subsequent laser treatment induced in-situ alloying and homogenization, resulting in dense, uniform AlNi coatings. The microstructure and chemical composition were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), while X-ray Diffraction (XRD) identified the formation of various phases, including Al₃Ni and AlNi₃ phases. The process demonstrated effective alloying and microstructural homogeneity, with residual alumina present at the surface. Despite the presence of some microstructural defects, such as cracking, this method provides a robust foundation for further refinement and opens new possibilities for tailoring alloy properties through combinatorial cold spray and laser alloying techniques.