压电振子阵列型超声喷丸强化*

为了提高超声喷丸强化加工的面积、效率及加工质量，对传统单振子超声喷丸强化技术进行了改进，提出了压电振子阵列型超声喷丸强化加工方法。分析了超声喷丸强化的机理，进行了压电振子的优化设计，分析了激振片的谐振响应，实验测试了系统样机在不同超声电源功率下弹丸撞击工件的区域分布；探究了超声电源功率、喷丸距离、弹丸直径和喷丸时间对加工样件显微硬度的影响，结果表明：以超声电源功率作为唯一变量，弹丸冲击工件表面的区域面积随超声电源功率增大而增大；7075铝合金样件的表面显微硬度及其提高率，随超声电源功率的增大、喷丸时间的增加、喷丸距离的减小及弹丸直径的增大而增大；超声电源功率为50W、喷丸时间为20min、喷丸距离为5mm、弹丸直径为1.5mm时喷丸效果最好，此时工件表面显微硬度增加量为65.1HV，表面显微硬度提高率为36.7%。压电振子阵列型超声喷丸强化技术可以有效增加喷丸冲击工件的面积，提高工件的表面显微硬度和加工效率。

Ultrasonic shot peening with piezoelectric vibrator array

In order to improve the working area, efficiency and quality of ultrasonic shot peening on the workpiece, the traditional ultrasonic shot peening with single ultrasonic vibrator is improved. A piezoelectric vibrator array ultrasonic shot peening method is proposed. The experimental prototype is designed and the mechanism of ultrasonic shot peening is analyzed. The optimal design of piezoelectric vibrator is carried out. The vibration response of the vibration disk is analyzed. The area distribution of the shot impacting the workpiece by using experimental prototype is tested under different ultrasonic power. The influence of ultrasonic power, shot peening distance, shot diameter, and shot peening time on the microhardness of the workpiece is explored. The combination of process parameters for the best shot peening effect on the surface of the workpiece is determined. The results show that taking the power of ultrasonic power supply as the only variable, the area of the impact area increases with the increase of the power of ultrasonic power supply, and the impact area is distributed in small intervals. After array ultrasonic peening, the surface microhardness and microhardness improvement rate of 7075 aluminum alloy increase with the increase of ultrasonic power, shot peening time, shot peening distance and shot diameter. The results show that the shot peening effect is the best when the ultrasonic power is 50W, the shot peening time is 20min, the shot peening distance is 5mm, and the shot diameter is 1.5mm. The surface microhardness of the workpiece is increased by 65.1HV, and the improvement rate of surface microhardness is 36.7%. The ultrasonic shot peening with piezoelectric vibrator array can effectively increase the impact area of shot peening on the workpiece, cause greater plastic deformation of the workpiece surface material, and improve the surface microhardness and shot peening efficiency of the workpiece.