Effect of multi-dimensional ultrasonic-assisted pulsed-laser surface irradiation on residual stress in AISI 1045 steel

The multi-dimensional ultrasonic-assisted pulsed-laser surface irradiation method was introduced to relieve the residual stress in the AISI 1045 steel specimen based on the Nd:YAG pulsed-laser machine. In this stress relief process, the acoustic energy was imposed into the AISI 1045 steel specimen accompanied by the pulsed-laser surface irradiation, which could be called as the multi-dimensional ultrasonic assisted stress relief (MDUASR). The mechanism of the MDUASR was discussed based on the thermal activation theory. In addition, the experiments for the MDUASR and the multi-dimensional ultrasonic stress relief (MDUSR) were carried out to validate the residual stress relieving effect and the energy saving effect of the MDUASR. The results show that the MDUASR has good effect on relieving residual stress and the MDUASR can reduce the energy consumption compared with the MDUSR. Furthermore, the mechanism of the MDUASR can be attributed to the metal softening effect and the dynamic stress effect. The findings confirm that the thermal energy induced by pulsed-laser surface irradiation can be adequately utilized to enhance the metal plasticity, which results in that the residual stress relieving effect of the MDUASR can be improved compared with the MDUSR. It can be concluded that the MDUASR belongs to an energy-saving and green environmental protection technology during the manufacturing process. (C) 2016 Elsevier Ltd. All rights reserved.