The invention relates to the technical field of additive manufacturing, and discloses an additive manufacturing hot-crack-free
precipitation strengthening high-temperature
alloy and a preparation method thereof.The method comprises the steps that a laying layer is divided into a plurality of parallel scanning strips according to the preset translation direction and the scanning strip interval, strip type scanning is conducted in a
laser autorotation and translation motion
coupling mode, and the high-temperature
alloy is obtained;
molten pool disturbance is remarkably enhanced, periodic shear fracture of the tip of dendritic
crystal is achieved, epitaxial growth of columnar
crystal is broken, grain equiaxalization is achieved, and
anisotropy is weakened; in addition,
laser scanning is a high-speed scanning strategy with the translation speed larger than or equal to 1500 mm / s, a shallow
molten pool is formed through regulation and control of the high scanning speed,
surface tension in the shallow
molten pool is utilized,
convection in the molten
pool is enhanced, dendritic crystals are refined, columnar crystals in the high-temperature
alloy are further reduced, and
anisotropy of mechanical properties is remarkably eliminated; and the transverse strength and
creep resistance at high temperature are improved. The isometric crystals can effectively prevent cracks from expanding in the orientation direction of the columnar crystals, and the fatigue life and the
damage tolerance are remarkably prolonged.