The invention belongs to the technical field of high-entropy alloys, and particularly relates to a high-
toughness CoCrNiAl series eutectic high-entropy
alloy additive manufacturing method. Aiming at the condition that traditional additive manufacturing
metal materials are insufficient in strength and
toughness, the invention provides the principle that in-situ refining of an additive manufacturing structure is realized through a fine and uniform B2 phase capable of being sheared by utilizing the characteristic of rapid solidification of additive manufacturing, so that the strength and
toughness are comprehensively improved. Based on the principle, the general formula of the eutectic high-entropy
alloy is CoaCrbNicAld, a is larger than or equal to 29 and smaller than or equal to 35, b is larger than or equal to 18 and smaller than or equal to 23, c is larger than or equal to 27 and smaller than or equal to 35, d is larger than or equal to 13 and smaller than or equal to 19, and a + b + c + d = 100. The eutectic high-entropy
alloy prepared through the
laser powder bed melting technology achieves high strength, high
ductility and
high fracture toughness under the condition that subsequent heat treatment is not needed. The design principle of the invention can also be popularized to other eutectic high-entropy alloy systems.