Abstract
The present study has investigated microstructural changes due to laser peening in modified 9Cr-1Mo steel subjected to creep. The EBSD or Electron Backscatter Diffraction studies have been made on round-bar type specimens creeping at applied stresses of230 and 240 MPa at 823 K and 105 MPa at 923K in air. Prior to the creep tests, laser peening was applied to some of the specimens at laser power of 8.4〜22GW/cm^2 per pulse in water. Microstructural changes in each specimen after its creep test was investigated by EBSD/SEM. The EBSD/SEM analyses revealed that the laser peening treatment makes creep rupture time longer and that the critical value of local misorientation value can be determined for creep rupture.
