Discussion on the thermal field produced by laser annealing for the residual stress relaxation

In this paper the temperature field generated on the surface of a metal by a focused laser source is analyzed. If the induced temperature distribution is properly designed the process can be used for obtaining local stress relaxation of the material. In order to determine the expected temperature distribution many parameters must be taken into account such as the power and the intensity distribution of the laser source, the duration of the irradiaton and the reflectivity of the surface at the specific wavelength. The influence of these parameters is numerically analyzed in this work. Temperature fields have been calculated for a point source and for a gaussian and a bi-gaussian beam in correspondence of different process parameters. Finally results in terms of stress relaxation for a given experimental configuration are presented based upon XRD residual stress measurements performed on an Al sample before and after the annealing process.