Multi-principal element alloy containing trace B and method for surface treatment of titanium alloy

The invention discloses a multi-principal element alloy containing trace B and a method for surface treatment of a titanium alloy. The multi-principal element alloy comprises, by mole, 23-30 parts of Al, 23-30 parts of Si, 23-30 parts of Cu, 1-5 parts of Ti, 21-30 parts of Zr and 1-4 parts of B. According to the method, a titanium alloy base material is cleaned and subjected to sand blasting roughening treatment, then plasma spraying equipment is used for spraying multi-principal element alloy powder on the surface of the titanium alloy base material, finally the plasma-sprayed surface is subjected to remelting treatment through a CO2 laser device, and a coating is obtained. The prepared multi-principal element alloy coating adopts characteristics of high-entropy effect, slow diffusion effect, nanophase reinforcement, super-high lattice deformation, cocktail effect and the like of the multi-principal element alloy, abrasion resistance and high temperature oxidation resistance of the titanium alloy are remarkably improved, and titanium fire can be prevented.