Method for eliminating selective laser melting molding cracks of 7075 aluminum alloy

Abstract

The invention discloses a method for eliminating selective laser melting molding cracks of a 7075 aluminum alloy. The method comprises the following steps that (1), under a protective atmosphere, 7075aluminum alloy raw powder and TiB2 submicron powder are subjected to ball milling and powder mixing, and powder obtained after ball milling and powder mixing is taken out and dried; and (2), the powder dried in the step (1) is added into a powder storing cylinder of selective laser melting molding equipment, selective laser melting is conducted after working parameters of the selective laser melting molding equipment are set, a 7075 aluminum alloy molded part is obtained, and finally heating and pressurizing treatment is conducted on the 7075 aluminum alloy molded part. According to the method, the TiB2 submicron powder capable of promoting nucleation is added into the 7075 aluminum alloy raw powder, the selective laser melting molding periodic cracks of the 7075 aluminum alloy are eliminated, and the molded part is put into a heating and pressurizing furnace to be heated and pressurized to improve the density of the part.

Description

technical field [0001] The invention relates to the technical field of 3D printing, and more specifically relates to a method for eliminating cracks formed by selective laser melting of 7075 aluminum alloy. Background technique [0002] Selective laser melting technology is an additive manufacturing technology that has great advantages in manufacturing complex geometric shapes, increasing material utilization, reducing costs and achieving rapid cooling during production. Selective laser melting technology has good application prospects in aerospace, automobile manufacturing, biomedicine and other fields, and has become a research hotspot in the field of metal additive manufacturing in recent years. The samples processed by selective laser melting technology of 7075 aluminum alloy have very serious periodic thermal cracks, and the formed samples have poor mechanical properties such as strength, toughness and hardness. At present, scholars have used the method of electrostati...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the deficiencies of the current selective laser melting technology, and provide a method for eliminating the processing cracks of 7075 aluminum alloy by selective laser melting technology and improving the density. It is mixed into the original powder of 7075 aluminum alloy as nucleation TiB 2 Submicron powder, so that the mixed powder suppresses the generation of thermal cracks in the selective laser melting process, but although the cracks are suppressed, but with the TiB 2 Addition of submicron powder to TiB in formed parts 2 The combination with the matrix is ​​not particularly strong, which reduces the density of the part. For this reason, the formed part is heated and pressed in a hot-press furnace, so that the density of the part is improved and the internal defects of the part are reduced.

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