Aluminum alloy powder for laser coaxial powder feeding additive manufacturing and application of aluminum alloy powder in repairing 5-series aluminum alloy

Abstract

The invention discloses aluminum alloy powder for laser coaxial powder feeding additive manufacturing and application of the aluminum alloy powder in repairing 5-series aluminum alloy. The aluminum alloy powder is composed of the following components in percentage by mass: 0.4-1.5 wt% of Si, 0.5-5.0 wt% of Mg, 0.15-0.8 wt% of Cu, 0.05-0.9 wt% of Mn, 0.15-0.7 wt% of Zn, 0.01-1.0 wt% of Cr, 0.2-1.2wt% of Ti, 0.1-2.0 wt% of Fe, 0.2-2.1 wt% of Zr, 0.2-2.1 wt% of Sc, 0.15-0.65 wt% of Ni, 0.2-2.5 wt% of TiB2, 0.1-0.9 wt% of Ce, and the balance of Al. The beneficial elements including Zn, Cr, Ti, Fe, Ni, TiB2 and Ce are added on the basis of the 5-series aluminum alloy, second phases such as a long-range ordered phase and a twin crystal phase are formed to form synergistic reinforcement of the elements, so that the anisotropy of the material is eliminated, meanwhile, the content of Si element is increased, then a eutectic structure is formed in the later period of laser cladding solidification, and the eutectic structure is used for supplementing hot crack pores caused by rapid solidification.

Description

technical field [0001] The invention belongs to laser cladding surface repair and surface modification technology, in particular to a laser coaxial powder feeding additive manufacturing aluminum alloy powder and its application in repairing 5 series aluminum alloys. Background technique [0002] 5xxx aluminum alloy has medium and high strength, good welding performance and corrosion resistance, and is widely used in transportation and structural engineering, such as bridges, aero-engine parts and fuselage panels, transport ships, and cranes. In recent years, with the development of science and technology industry at home and abroad, in order to reduce the weight of the machine itself, aluminum alloys have gradually replaced steel materials. However, aluminum alloys are often affected by external large stresses during service, including surface friction and reciprocating unloading and loading, resulting in surface fatigue, cracks, pores and other defects. Therefore, a large ...

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Problems solved by technology

[0003] At present, there are many problems and defects in Al-Mg-Sc-Zr alloy powder used directly for laser repair. The repair coating has obvious growth of columnar crystals, a large number of pores between dendrites, and easy cracking for repairing a wide area, resulting in low comprehensive strength of the repair layer. , low fatigue resistance

The existing research patents are all Al-Mg-Sc alloy powders used in powder bed laser additive manufacturing. They are directly used in laser coaxial powder feeding additive manufacturing, which is prone to problems such as low mechanical properties and cracks.

Because powder bed additive manufacturing and powder feeding additive manufacturing are different types of additive manufacturing methods, the former has a fast cooling rate, the grains are not easy to grow, and the mechanical properties are high; but the latter is easy to grow grains, and the precipitation is relatively coarse

In the patent with the publication number CN109175350A, a kind of Al-Mg-Mn-Sc-Zr aluminum alloy powder and its preparation method for additive manufacturing are disclosed, which strengthens the Al-Mg alloy by adding Sc and Zr elements, although The strength of aluminum alloy reaches 450MPa, but it is inevitable that defects such as cracks and holes will appear during the printing process, and it is difficult to eliminate the anisotropy between it and the base material

Furthermore, the above-mentioned aluminum alloy powder formula is difficult to be used in the repair process of coaxial powder feeding, because during the repair process, the repair coating columnar crystals grow obviously and there are holes, which are very easy to crack when used for large-scale repair

The patent with the publication number CN107881382A discloses a special rare earth modified high-strength aluminum alloy powder for additive manufacturing. Strength, but the strength is still lower than 300MPa, mainly due to the neglect of the synergistic effect of other elements on the strength of the alloy. The parts printed by this system will still have anisotropy and a large proportion of columnar crystals.

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