Abstract

The effect of laser action on the formation of microcracks on the inclusion–matrix boundaries during plastic deformation was investigated. It was shown that the local microwelding under laser action contributes to increase the cohesive strength of these boundaries. It was established the influence of temperature and speed of deformation, as well as an energy and duration of the laser pulse on the parameters of origin and development of brittle separations. It was shown that under sudden heating and cooling the complex mechanism of relaxation processes on the boundaries having shear-diffusion-phase character can be realized. Transformation of inclusion–matrix boundaries under high-temperature brittle separation combining plastic and brittle stresses relaxations on that boundaries which causes by high-speed laser strengthening was investigated. It was defined the energy range of the laser beam (18...25J)at which these effects are maximized. It has been shown that under combining laser treatment of steel and high-temperature deformation the two mechanisms of strengthening of interphase inclusion–matrix boundaries are realized: laser strengthening (high-speed thermal variant when strengthening is many factors process) and deformation strengthening.