Ultrasonic impact treatment (UIT) could improve the residual stress of additive manufactured parts. However, there is almost no report on the effect of in-situ UIT, where the UIT equipment moves with laser metal deposition (LMD) equipment at a controllable offset, on residual stress. In this work, the effect of in-situ UIT on residual stress and the effect of offset on the effectiveness of in-situ UIT were investigated by finite element analysis. The stress change introduced by in-situ UIT includes the impact and cooling process. The results show that the value of residual compressive stress (RCS) introduced by the impact of in-situ UIT is higher than that after ex-situ UIT. In the cooling process, the unfinished shrinking behavior reduces it. The increasing offset has little influence on the residual stress field introduced by the impact of in-situ UIT. Residual compressive stress (RTS) reappears in the deposition layer after the cooling process of in-situ UIT, when the offset is small, increasing the offset can retain the RCS. In-situ UIT can improve the residual stress field and the impact of in-situ UIT becomes increasingly similar to that of ex-situ UIT as the offset increases. The findings serve as invaluable guidance in devising strategies to manage and mitigate residual stress in components produced by LMD and other additive manufacturing techniques.

中文翻译：

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原位超声冲击处理对激光沉积层残余应力的影响

超声波冲击处理（UIT）可以改善增材制造零件的残余应力。然而，几乎没有关于原位UIT（UIT设备与激光金属沉积（LMD）设备以可控偏移量移动）对残余应力影响的报道。在这项工作中，通过有限元分析研究了原位UIT对残余应力的影响以及偏移对原位UIT有效性的影响。原位UIT引入的应力变化包括冲击和冷却过程。结果表明，原位UIT冲击引入的残余压应力（RCS）值高于异位UIT后的值。在冷却过程中，未完成的收缩行为会减少它。增加的偏移距对原位UIT冲击引入的残余应力场影响不大。原位UIT冷却过程后，沉积层中会重新出现残余压应力（RTS），当偏移量较小时，增加偏移量可以保留RCS。原位UIT可以改善残余应力场，并且随着偏移量的增加，原位UIT的影响与异位UIT的影响越来越相似。这些研究结果对于制定管理和减轻 LMD 和其他增材制造技术生产的部件残余应力的策略具有宝贵的指导意义。