High-Speed Laser Metal Deposition of CrFeCoNi and AlCrFeCoNi HEA Coatings with Narrow Intermixing Zone and their Machining by Turning and Diamond Smoothing

The processing of high-entropy alloys (HEAs) via laser metal deposition (LMD) is well known. However, it is still difficult to avoid chemical intermixing of the elements between the coating and the substrate. Therefore, the produced coatings do not have the same chemical composition as the HEA feedstock material. Single-layer CrFeCoNi and AlCrFeCoNi HEA coatings were deposited using high-speed laser metal deposition (HS-LMD). Elemental mapping confirmed a good agreement with the chemical composition of the powder feedstock material, and revealed that chemical intermixing was confined to the immediate substrate interface. The coatings are characterized by a homogeneous structure with good substrate bonding. The machining of these coatings via turning is possible. Subsequent diamond smoothing results in a strong decrease in the surface roughness. This study presents a complete manufacturing chain for the production of high-quality HS-LMD HEA coatings.