1. Influence of ultrasonic impact characteristics on stress distribution of LMD deposition layer.
- Author
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Wei, Xu, Zhang, Laiqi, and Li, Xianlong
- Subjects
STRESS concentration ,ASSISTIVE technology ,ACCELERATION (Mechanics) ,ULTRASONICS ,VELOCITY ,RESIDUAL stresses - Abstract
Ultrasonic impact treatment (UIT) is a kind of mechanical assistive technology that can reduce the residual stress of the as-deposited metal parts. Up to now, the mechanism of ultrasonic characteristics affecting the residual stress has not been revealed distinctly. In this work, the 1Cr12Ni3MoVN deposition layer was treated by UIT with multiple ultrasonic characteristics. The results show that UIT transforms the residual tensile stress of the LMD deposition layer into compressive stress. As the amplitude increases from 20 to 30 μm, the maximum and depth of transverse residual stress observed in the vertical direction increased from 354 to 381 MPa and from 0.364 to 0.523 mm. The maximum and depth of longitudinal residual stress increased from 258 to 318 MPa and from 0.482 to 0.785 mm. As the frequency increases from 15 to 25 kHz, the maximum and depth of transverse residual stress observed in the vertical direction increased from 207 to 406 MPa and 0.301 to 0.395 mm. The maximum and depth of longitudinal residual stress increased from 240 to 326 MPa and from 0.341 to 0.517 mm. The influence of ultrasonic frequency is not as prominent as ultrasonic amplitude. The maximum impact velocity of the pin is the major factor determining the residual compressive stress field. The acceleration of the pin is positively correlated with the downward velocity of the horn. Increasing the ultrasonic amplitude can effectively increase the velocity of the horn. Once the impact energy is large enough, the σ
max is basically unchanged, but the increase of impact energy can still increase the d. This work is of guiding significance for the elimination and control of residual stress in parts manufactured by LMD and other additive manufacturing methods. [ABSTRACT FROM AUTHOR]- Published
- 2024
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