红外-蓝光复合激光熔覆制备CuCr50合金抗电弧侵蚀性能OA

CuCr50 alloy is widely used as contact material in vacuum interrupters due to its excellent electrical conductivity and arc erosion resistance.However,conventional arc-melted CuCr50 alloy exhibits coarse and non-uniformly distributed Cr phases due to slow cooling rate,which limits its mechanical properties and arc erosion resistance,making it difficult to meet the increasing demands of high-voltage power equipment.This study employs infrared-blue hybrid laser cladding technology to fabricate CuCr50 coatings on pure copper substrates,aiming to refine the Cr phase through rapid solidification effects and enhance the mechanical properties and arc erosion resistance of the material. CuCr50 coatings were prepared on pure copper substrates using an infrared-blue hybrid laser cladding system consisting of a 6 000 W infrared fiber laser(1 064 nm)and a 2 000 W blue diode laser(450 nm),with cladding parameters set as:blue laser power 1 800 W,infrared laser power 1 200 W,scanning speed 10 mm/s,powder feeding rate 12 g/min,overlap ratio 50%.The commercial arc-melted CuCr50 alloy was used as reference.The microstructure was characterized by SEM,and Cr particle size was statistically analyzed.Phase composition and lattice changes were analyzed by XRD.Vickers hardness was measured along the cross section,and electrical conductivity was tested.Arc erosion tests were conducted through the JF04D electrical contact testing system at 24 V DC with currents of 10,20 and 30 A for 1 000 operations.Mass change was measured,and crater morphology was observed by 3D profilometer. The laser-cladded CuCr50 coating exhibited significantly refined Cr phases with an average grain size of 2.24 μm,representing a 92.9%reduction compared with the arc-melted commercial alloy(31.4 μm).XRD analysis revealed a low-angle shift of the Cu diffraction peak,indicating lattice expansion caused by supersaturated Cr atoms dissolved in the Cu matrix due to rapid solidification.The average hardness of the laser-cladded coating reached 164.1HV0.5,which was 58.1%higher than that of the commercial alloy(103.8HV0.5)and 127.9%higher than that of the pure copper substrate(72HV0.5).The electrical conductivity of the coating was 29.9%IACS,slightly lower than that of the commercial alloy(38.4%IACS).According to Matthiessen rule,this was mainly attributed to enhanced electron scattering caused by solute atoms.Arc erosion tests indicated that the mass transfer direction for both materials was from cathode to anode.The laser-cladded coating exhibited lower total mass loss at currents of 10 A,20 A,and 30 A,measured at 0.07,0.1 and 0.1 mg,respectively,compared with 0.1,0.4 and 0.5 mg for the commercial alloy.It also showed lower arc energy and arc duration at all tested currents.The coating displayed more uniform erosion morphology with a maximum crater depth of 13.936 μm,comparable to that of the commercial alloy(13.205 μm),while its overall arc erosion stability was significantly better. The rapid solidification effect of laser cladding synergistically improves hardness and arc erosion resistance through Cr phase refinement.The refined Cr phase significantly increases grain boundaries,enhancing hardness through grain refinement and dispersion strengthening.The uniformly dispersed Cr phase effectively disperses arc energy,suppresses local heat accumulation,thereby reducing arc energy and arc duration and improving erosion uniformity.Although the supersaturated solid solution leads to a slight decrease in electrical conductivity,it remains acceptable for engineering applications.This study provides a novel approach for surface modification of CuCr50 alloy for vacuum interrupters.