Abstract
In this paper, the ((CoCrFeNi)95Nb5)100−xMox (x = 1, 1.5 and 2) high-entropy alloy (HEA) coatings were fabricated on the substrate of 45# steel by laser cladding process under different laser beam power. The influence of laser beam power and molybdenum element content on the microstructure and microhardness of the HEA coatings was investigated. Results show that the HEA coatings were composed of face-centered cubic (FCC) phase and Laves phase, had low porosity, and bonded well to the substrate. The Mo1 coating is composed of cellular dendritic structures and columnar dendritic structures. With the increase of molybdenum element content, the columnar dendritic structures disappeared, the grains are refined, and the arrangement of grains is more compact. The volume fraction of the interdendritic phase under the laser beam power of 800 W was small and irregular. After the laser beam power was increased to 1000 W, the volume fraction of the interdendritic phase was increased. Under the laser beam power of 1200 W, the volume fraction of the interdendritic phase was small again. Therefore, the coatings fabricated under the laser beam power of 1000 W had a larger volume fraction of the interdendritic phase and higher microhardness. With the increase in molybdenum content, the grain changed from columnar dendrite to cellular dendrite, and the microhardness of the coating increased. The characteristics of the laser cladding process, the formation of Laves phase, and the fine grain strengthening lead to high microhardness of the coatings.
Highlights
95Nb55 high-entropy alloy (HEA) coating was successfully fabricated on the substrate of
A new phase can be found in the HEA coatings and the may be caused by the preferential orientation
Results show that the HEA coatings consist of face-centered cubic (FCC) phase and Laves phase
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Most of the bulk HEAs have been prepared by casting. A reasonable way to solve this problem is to develop HEA coatings on the substrate of conventional materials. °C·s−11),),little the substrate, and excellent metallurgical bonding, the laser cladding technology shows application potential potential in the preparation of HEA coatings [14,15,16]. In the process of synchronous laser cladding, the raw material is directly blown into the laser action zone, and it shortens the pretreatment pretreatmentprocess processand andhas has little requirement surface morphology ofsubthe the little requirement on on thethe surface morphology of the substrate [17,18,19,20].
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