Microstructures evolution, formation mechanisms and properties of Sicp/ Al composite coatings on Ti-6Al-4v substrate via mechanical alloying method

Abstract

In this present work, high-energy mechanical alloying method was successfully applied to fabricated Al-SiC coatings, which possessed a composite structure. The coatings fabricated by different Al-SiC weight ratio were studied. The results of scanning electron microscope(SEM) and Energy Dispersive X-ray spectrometer(EDS) revealed the microstructures and phase compositions of as-synthesized coatings, respectively. To test the mechanical properties of coated samples prepared at different Al content, the tests of microhardness value were carried out from the outermost coating to the inner substrate. Then, the effect of milling duration on coatings was also studied. Adhesion behaviors of the coatings at different milling time were investigated through scratch tests. And friction and wear resistance were also tested. Which further confirmed the surface strengthening effect of the coating. The formation mechanisms of the Al–SiC composite coating and Al–SiC composite powder were elaborated. Overall consideration of microstructure, phase composition and mechanical properties, the coating prepared with Al–SiC raw powder ratio of 65:35 at 7 h milling time was the optimal processing parameters on fabrication of Al–SiC composite coating. The Al–SiC coating shows high performance in adhesion behaviors and wear resistance, this method is capable to be applied to fabricate coatings on the inner walls of tubular specimens .