Microstructure and dry sliding wear behavior of laser clad AlCrNiSiTi multi-principal element alloy coatings

The approximately equimolar ratio AlCrNiSiTi multi-principal element alloy (MPEA) coatings were fabricated by laser cladding on Ti-6Al-4V (Ti64) alloy. Scanning electron microscopy (SEM), equipped with an energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to characterize the microstructure and composition. Investigations show that the coatings consist of (Ti, Cr)(5)Si-3 and NiAl phases, formed by in situ reaction. The phase composition is initially explicated according to obtainable binary and ternary phase diagrams, and the formation Gibbs energy of Ti5Si3, V5Si3 and Cr5Si3. Dry sliding reciprocating friction and wear tests of the AlCrNiSiTi coating and Ti64 alloy substrate without coating were evaluated. A surface mapping profiler was used to evaluate the wear volume. The worn surface was characterized by SEM-EDS. The hardness and wear resistance of the AlCrNiSiTi coating are well compared with that of the basal material (Ti64). The main wear mechanism of the AlCrNiSiTi coating is slightly adhesive transfer from GCr15 counterpart, and a mixed layer composed of transferred materials and oxide is formed.