Method for repairing flaws of titanium-aluminum intermetallic compound castings

Abstract

The invention belongs to the technical field of additive repairing, and relates to a method for repairing flaws of titanium-aluminum intermetallic compound castings. A vacuum environment condition isadopted in the whole process of electron beam fuse repairing, vacuum pressure intensity is 10<-2>Pa to 10<-3>Pa, and thus pollution caused by harmful elements such as N, O and H in the repairing process can be effectively avoided. Laser cladding repairing and arc welding repairing methods can hardly avoid pollution caused by harmful elements such as N, O and H, especially in a high-temperature state, the harmful elements can strongly cause embrittlement and cracking of titanium-aluminum intermetallic compounds, and then repairing fails. The material metallurgical quality after repairing in thevacuum environment is superior to that of other repairing methods, and repairing flaws can be effectively avoided; in addition, the heat loss speed is low under the vacuum environment, and after repairing, the cooling speed is low and heat stress is low, so that the risk of cracks is greatly lowered. Through vacuum annealing treatment in a furnace after repairing, repairing stress can be removedin time, the structure of a repaired area can be regulated, and delayed cracks of the repaired castings can be effectively avoided.

Description

technical field [0001] The invention belongs to the technical field of additive repair and relates to a method for repairing defects of titanium-aluminum intermetallic compound castings. Background technique [0002] TiAl intermetallic compound has low density, high modulus and excellent high temperature strength, creep resistance, oxidation resistance and flame retardancy, so it is recognized as the most promising high temperature structural material. However, due to the high melt viscosity, insufficient feeding ability and low plasticity of TiAl intermetallic compounds, the castings are prone to pits, shrinkage cavities, porosity, cracks and other defects, which have become one of the bottlenecks in its engineering application. In order to improve the qualified rate of castings and reduce production costs, it is necessary to break through the defect repair technology. [0003] The TiAl intermetallic compound itself has few slip systems, difficulty in dislocation movement ...

AI Technical Summary

Problems solved by technology

In addition to the poor atmosphere protection conditions of the argon arc welding method, the repair operation of the parts after high temperature preheating is difficult and cracks are easy to occur

[0004] The currently disclosed methods of electron beam welding of titanium-aluminum intermetallic compounds use no filler material or only use a transition layer material on the surface to be welded. The purpose is to weld and connect the two components as a whole, which cannot be used for the repair of casting defects.

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