关键词: 激光熔覆, 超声振动, 施加方式, 施加角度

Abstract: To study the optimization effects of ultrasonic vibration on laser cladding, the method of ultrasonic vibration applied to the cladding layer directly was introduced to prepare the high performance cladding layers of 3540Fe/CeO2, on the basis of determining the optimal processing parameters and the powder proportions. The influences of the applying method and the applying angles of the vibration on the macroscopic morphologies, microstructures, phase compositions and mechanics properties of the cladding layers were compared. The experimental results show that ultrasonic vibration improves the morphologies of the laser cladding layers obviously, when the applying angle is as 45°, the effect is optimal. The ultrasonic vibration may refine the organization and reduce the porosity without changing phase compositions, the coating tissues are transformed into equiaxed crystals and fine needle-like dendrites composed of the phases γ(Fe, Ni), Cr13Ni5Si2, Cr7C3 and so on. After the ultrasonic vibration is added, the average hardness of the cladding layers increases by 62% and reaches 1 148 HV. The friction coefficient decreases significantly, the abrasion loss decreases and the wear resistance improves. Through the scanning electron microscope （SEM） observation of the abrasions, the ultrasonic vibration may improve the wear form, the wear form of the specimen changes from adhesive wear mainly to regular abrasive wear, and the wear surfaces are smoother.

Key words: laser cladding, ultrasonic vibration, applying method, applying angle