Effects of processing parameters on residual stress fields of 2024-T351 alloy blade subjected to massive double-sided laser peening treatment

Abstract

Double-sided laser shot peening (DSLSP) is a promising technique for improving mechanical properties for thin-section components. Residual stress (RS) field induced in the thin 2024-T351 alloy blade by DSLSP was investigated through experiments and finite element simulation. The effects of key parameters, such as pulse scanning patterns, overlapping rates, and DSLSP modes, on the RS field were analyzed. The model was validated by comparing the simulation results with experiment data. The results revealed that the scanning patterns advertently influenced the RS distribution, and compressive residual stresses were found to exist inside the curved thin-section blade. The overlapping rate of 70% could drive the tensile stress (TS) distributed at the near-surface into a fully compressed state, while it could also cause a large-scale TS concentration at the edge of the blade. Moreover, the mechanism of shock wave reflection-coupling on RS distribution with two DSLSP modes was also clearly revealed. The alternate double-sided laser peening mode would greatly limit the edge stress concentration and result in a better RS distribution.