Directional freezing styloid or single-crystal nickel-base high-temperature alloy repairing or coating method

Abstract

The invention belongs to a preparation technique of the metal surface settled layer, in particular to a method for preparing the directional solidification column crystal or single crystal settled layer which grows on the extension of the surface of the directional solidification column crystal or single crystal high temperature alloy. The proposal of the invention solves the problem of repairing and coating of the directional solidification column crystal or single crystal high temperature alloy; and to gain a compact and flawless directional solidification column crystal or single crystal settled layer which is matched with the directional solidification column crystal or single crystal. The invention discloses an extension high power differential arc spark metal deposition technique. The invention has the advantages of wide process window achieved by the extension high power differential arc spark metal deposition technique, no heat damage to the ferronickel high temperature alloy, narrow heat influence area or no heat influence area, being capable of effectively avoiding the phenomenon of heat flaw of the ferronickel high temperature, no complicated devices such as vacuum room needed and no preheating needed.

Description

technical field [0001] The invention belongs to the preparation technology of a metal surface deposition layer, in particular to a method for preparing a directionally solidified columnar crystal or a single crystal deposition layer grown epitaxially on the surface of a directional solidified columnar crystal or a single crystal superalloy. Background technique [0002] Superalloys and their high-temperature protective coating systems play a pivotal role in aero-engines. At present, in advanced aero-engines, directionally solidified columnar crystals and even single crystals have gradually replaced traditional polycrystalline superalloys and are widely used. Due to the high price of directionally solidified columnar crystals and single crystal parts, in order to prolong these advanced superalloy parts as much as possible It is very important to research and develop superalloy directional solidification epitaxial deposition technology for repair and coating. [0003] The eme...

AI Technical Summary

Problems solved by technology

However, just as the researchers of the Swiss Federal Institute of Technology pointed out in the literature, the laser treatment of high-strength nickel-based superalloys still has great limitations, specifically in: (1) nickel-based superalloys are sensitive to thermal cracks It is highly resistant, and it is easy to generate thermal cracks during laser processing. The solution to this problem is to preheat the workpiece to above 700°C for processing. However, research has shown that epitaxial growth of single crystals can only be achieved without preheating.

This near-contradictory result makes epitaxial deposition only possible on alloys with relatively good weldability.

(2) Under laser treatment conditions, the process parameters strongly affect the final solidification microstructure, the directional solidification process window is narrow, and the heat accumulation during processing is relatively large, which makes it difficult to control continuous columnar growth

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