Effects of Cu content and mechanical alloying parameters on the preparation of W–Cu composite coatings on copper substrate

• Mechanical alloying could be beneficial to the preparation of coatings with immiscible system.
• Thicker, denser and well bonded W-Cu coatings were successfully fabricated on copper surface.
• Effects of mechanical alloying process parameters on formation of coatings were presented.
• Optimized process parameters for the fabrication of W-Cu coatings had been acquired.

A novel surface coating preparation technique utilizing high-energy mechanical alloying (MA) method was used to deposit tungsten–copper composite coatings on pure copper surface using a planetary ball mill. The microstructures and elemental and phase composition of mechanically alloyed coatings at different process parameters were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS). The effects of mechanical alloying parameters on the fabricating of tungsten–copper composite coatings had been investigated. Fully dense and uniform tungsten–copper composite coatings were metallurgically bonded on the copper substrate, with an average thickness of ∼65 μm under the optimized mechanical alloying parameters (i.e., rotation speed of 350 rpm, milling time of 9 h and powder ratio of W–30 wt.%Cu). Microhardness tests were carried out to examine the mechanical properties of the coatings. The results showed that the maximum microhardness of the coatings reached HV0.1 193, showing a great improvement upon pure copper substrate. Mechanical alloying is a complex process and hence involves optimization of a number of variables to achieve the desired results. In this work, effects of the main parameters on the preparation of tungsten–copper composite coatings were properly presented.