Laser testing method and device for thermal fatigue property of surface discretization strengthening material

The invention discloses a laser testing method for the thermal fatigue property of a surface discretization strengthening material, which can perform directional induction on crack growth, in-situ observation on the crack and carry out evaluation on thermal fatigue property of a strengthening point self and retardation of the strengthening point to the crack growth. The method comprises the follow steps: (1), using a beam homogenizing device to transform the light distribution of laser spots from Gaussian distribution into uniform distribution; (2), using a beam shaping element to change the shapes of the laser spots from circles into rectangles; (3), changing parameters of the beam shaping element and adjusting the length-width ratio of the laser spots; (4), heating the front side of the material through the laser spots when the laser spots pass through a strengthening area along a prescribed route in a scanning manner, so as to enable the heated material to reach an actual usage temperature of the surface discretization strengthening material; (5), cooling the rear side of the material by using water-cooling copper blocks; (6), stopping the laser to enable the material to be cooled to the original temperature, repeating the heating and cooling steps, that is, continuously heating the material until crack occurs; (7), performing evaluation on the surface discretization effect. The invention further provides a device adopting the laser testing method for the thermal fatigue property of the surface discretization strengthening material.