▎ 摘　　要

NOVELTY - Preparation of laser-induced composite cladding graphene-reinforced nickel-titanium composite material involves adding nickel-chromium alloy powder and titanium power having purity of 99.4% to surface-modified graphene, mixing obtained mixed powder in a ball mill filled with liquid nitrogen at 200 rpm for 2 hours, obtaining cladding powder having a particle size of 20-60 mu m, degreasing the surface of pure titanium plate as a substrate, etching, and depositing cladding powder on the surface of the substrate by laser cladding method at laser power of 2.5 kW. USE - Preparation of laser-induced composite cladding graphene-reinforced nickel-titanium composite material used for shape memory alloy and biomedical material. ADVANTAGE - The method enables preparation of laser-induced composite cladding graphene-reinforced nickel-titanium composite material with excellent corrosion resistance and wear resistance. DETAILED DESCRIPTION - Preparation of laser-induced composite cladding graphene-reinforced nickel-titanium composite material involves adding nickel-chromium alloy powder and titanium power having purity of 99.4% to surface-modified graphene, mixing obtained mixed powder in a ball mill filled with liquid nitrogen at 200 rpm for 2 hours, obtaining cladding powder having a particle size of 20-60 mu m, degreasing the surface of pure titanium plate as a substrate, etching, and depositing cladding powder on the surface of the substrate by laser cladding method at laser power of 2.5kW, laser scanning speed of 1500 mm/minute, powder nozzle diameter of 4 mm, laser spot diameter of 4.5 mm, cladding powder flow rate of 40 g/minute, powder nozzle and pure titanium plate surface normal angle of 53 degrees and powder nozzle and pure titanium plate surface vertical distance of 12 mm. The mass ratio of titanium powder and nickel-chromium alloy powder is 1:8. The content of surface-modified graphene in the mixed powder is 3.5 %mass. Stainless steel balls having grain size of 3-20 mm are added to ball mill. The mass ratio of stainless steel balls and mixed powder is 10:1. The average particle size of titanium powder is 90 mu m. The nickel-chromium alloy powder comprises 80 wt.% nickel and 20 wt.% chromium, and has average particle diameter of 100 mu m. The surface-modified graphene is prepared by adding graphene to 8% sodium hydroxide solution, ultrasonically dispersing at 35 degrees C for 60 minutes, separating graphene, washing with deionized water, coarsening, adding roughened graphene to a mixture of 50 mL/L acetic acid and 45 mL/L stannous acetate, ultrasonically dispersing at 55 degrees C for 60 minutes, separating graphene, washing with deionized water, activating, adding activated graphene to 28 g/L sodium borohydride solution, ultrasonically dispersing at 45 degrees C for 60 minutes, washing with deionized water until neutral, vacuum-drying at 100 degrees C for 120 minutes, reducing dried graphene, adding reduced graphene to a nickel plating solution comprising 45 g/L nickel acetate, 38 g/L aminoacetic acid, 25 g/L potassium pyrophosphate, 0.05 g/L palladium acetate and 5-20 ml/L 25% aqueous ammonia, and having pH of 11, ultrasonically vibrating at 70 degrees C, and performing electroless nickel plating for 80 minutes. The average thickness of nickel cladding layer on the surface of the graphene is 10 mu m.