Precipitation strengthening nickel-based high-temperature alloy laser powder bed melting forming method capable of reducing hot cracks

Abstract

The invention provides a precipitation strengthening nickel-based high-temperature alloy laser powder bed melting forming method capable of reducing hot cracks. According to the method, rare earth element oxide particles and precipitation strengthening nickel-based high-temperature alloy powder are mixed and then subjected to laser powder bed melting forming, the rare earth element oxide particles and the precipitation strengthening nickel-based high-temperature alloy powder interact under the action of continuous laser, and therefore harmful elements in the original precipitation strengthening nickel-based high-temperature alloy powder can be enriched, segregation of the harmful elements along the crystal boundary is reduced, forming of a liquid film of melt at the final stage of solidification is correspondingly hindered, and the hot cracks are greatly reduced.

Description

technical field [0001] The invention relates to the technical field of mechanical manufacturing, in particular to a method for laser powder bed fusion forming of precipitation-strengthened nickel-based superalloys for reducing thermal cracking. Background technique [0002] The laser powder bed fusion forming method is a commonly used and fastest-growing technology in the field of metal 3D printing in recent years, and has attracted extensive attention from industry and academia. During the forming process, the computer system controls the high-energy laser beam to selectively melt the metal powder, and realizes the rapid forming of complex parts by layer-by-layer accumulation, which has the advantages of material saving and high dimensional accuracy. (such as nickel-based nickel-based superalloys, aluminum alloys, titanium alloys, stainless steel, etc.) [0003] However, there are great technical difficulties in precipitation-strengthened nickel-based superalloy parts that...

AI Technical Summary

Problems solved by technology

However, for the precipitation-strengthened nickel-based nickel-based superalloys that have been served at high temperatures for a long time and maintain a stable structure, most of the commonly used refiners cannot refine the structure, so they are not suitable for solving the problem of laser powder bed melting. The problem of thermal cracking in forming

[0005] Although some domestic and foreign researches have been carried out to improve the hot cracking of nickel-base superalloys cast by laser powder bed fusion forming method and achieved certain results (see "Selective laser melting of the hard-to-weld IN738LC superalloy: Efforts to mitigate defects and the resultant microstructural and mechanical properties", H.Wang et al., Journal of Alloys and Compounds, Vol. 807), but for the same alloy powder from different powder suppliers or different batches of alloy powder raw materials from the same supplier and different 3D The combination of printing equipment needs to re-explore the appropriate process parameters, and the time cost is high

In addition, for precipitation-strengthened nickel-based superalloys with high content of alloying elements aluminum and titanium, the process window of laser powder bed fusion forming is extremely small, and the process stability cannot be guaranteed.

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