Tailoring the composition and microstructure of W-based coatings on metallic sheets by varying the type and combination of milling balls

Abstract

W-based alloyed coatings with variable W content (90, 80, 75, and 55 wt%) were fabricated on Ti and steel substrates using a mechanically vibrated vial with different combinations of W milling balls. The resulting W-based coatings displayed heterogeneous nanocomposite structures; the composition and microstructures of which could be tailored through the selection of milling balls. The average size of the W grains ranged from 6 to 10 nm and increased with decreasing W content. The 90, 80, and 75 wt% W coatings exhibited amorphous matrix interphases; the 75 W coating also displayed amorphous and crystalline multicomponent oxide dispersions. The formation of these structures was governed by the intensity of milling and was driven by plastic deformation, deformation-induced intermixing, alloying, and atomic interactions. The 90 W coating exhibited the highest hardness value of 1200 HV, which decreased with an increasing fraction of the matrix phase. The W coatings greatly enhanced the wear resistance of the substrate surface with the wear rate value being seven times lower than that of an uncoated Ti surface. These results demonstrate the efficacy of using W milling balls to fabricate W-based coatings on various metallic substrates and the potential for tailoring their properties to specific applications.