Method for repairing titanium alloy components

Abstract

A method for repairing a titanium alloy surface of a turbine component includes the step of cold gas-dynamic spraying a powder material comprising at least one titanium alloy directly on the titanium alloy surface. The method may further include the steps of hot isostatic pressing the cold gas-dynamic sprayed turbine component, and performing a separate heat treating step after the hot isostatic pressing. Thus, the cold gas-dynamic spray process and post-spray processing can be employed to effectively repair degraded areas on compressor turbine components.

Description

TECHNICAL FIELD [0001] The present invention relates to repair and overhaul of turbine engine components. More particularly, the present invention relates to methods for repairing turbine engine components made from titanium alloys. BACKGROUND [0002] Turbine engines are used as the primary power source for many types of aircrafts. The engines are also auxiliary power sources that drive air compressors, hydraulic pumps, and industrial gas turbine (IGT) power generation. Further, the power from turbine engines is used for stationary power supplies such as backup electrical generators for hospitals and the like. [0003] Most turbine engines generally follow the same basic power generation procedure. Compressed air generated by axial and / or radial compressors is mixed with fuel and burned, and the expanding hot combustion gases are directed against stationary turbine vanes in the engine. The vanes turn the high velocity gas flow partially sideways to impinge on the turbine blades mounted...

AI Technical Summary

Problems solved by technology

The LPC / HPC components are subjected to stress loadings during turbine engine operation, and also are impacted by foreign objects such as sand, dirt, and other such debris.

The LPC / HPC components can degrade over time due to wear, erosion and foreign object damage.

Sometimes LPC / HPC components are degraded to a point at which they must be repaired or replaced, which that can result in significant operating expense and time out of service.

There are several traditional methods for repairing damaged turbine engine components, and each method has some limitations in terms of success.

One primary reason for the lack of success is that the materials used to make LPC / HPC components do not lend themselves to efficient repair techniques.

However, repairing the compressor blade with conventional welding techniques subjects the compressor blade to high temperatures at which the welding areas are oxidation-prone.

Maintaining such a controlled environment is inefficient in terms of both time and expense.

Also, conventional techniques for repairing titanium alloy components which are made of alpha-beta alloys with high beta stabilizers such as Ti-6Al-2Sn-4Zr-6Mo possibly cause the components to crack while in a welding zone and / or a heat-affected zone because the alloy components have limited weldability.

However, combining preheating and welding is inefficient in terms of both time and expense.

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