The Simulation and Experiment of In 718 in Warm Laser Shock Processing Without Coating

A modified constitutive model, combining laser shock processing and dynamic strain aging (DSA), is used to obtain the compressive residual stress field of In 718 in warm laser shock processing (WLSP) by ABAQUS VUMAT subroutine. In this work, a constitutive model with DSA is simplified by a single equation to integrate the interactions of face-centered cubic (FCC) and body-centered cubic (BCC) crystal structure. The modified Voyiadjis-Abed-Song (VAS) constitutive model is imported by a procedure code developed independently, including the Mises yield criterion application and parameter update. Based on the constitutive model and Gaussian mode laser wave, the strengthen process of WLSP in In 718 is simulated. For the experiment, 30x30x4 mm In718 specimen is strengthened by WLSP without coating. We analyze the amplitude and distribution of residual stress to explore the effect of temperature in impact regions through experiment and simulation. Predicted by the modified VAS constitutive model, the residual stress predicted by the modified VAS constitutive model agrees well with the experimental data at various temperatures. As a result, temperature softening has obvious effect on the residual stress distribution for In 718 in WLSP at 200 degrees C. At 300 degrees C, the residual stress amplitude has no diminution compared with 200 degrees C due to DSA active, even there is thermal softening. DSA promotes the diffused solute atoms gathering and dislocation multiplication, that makes a flow stress reduce at a temperature range.