Oxidation-Resistant Turbine Blade Tip With Graded MCrAlY
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Solution Overview
Problem
Modern gas turbines face issues with oxidation of turbine blade tips, leading to material stripping and reduced lifespan due to exposure to hot, oxidizing combustion gases, which existing solutions like conservative design or ceramic coatings fail to adequately address without compromising efficiency or increasing cooling air consumption.
Innovation Solution
A turbine blade design featuring a main body of one material and a blade tip made of an oxidation-resistant MCrAlY alloy, with a graduated composition and integrated ceramic particles, applied using additive manufacturing methods like laser application welding, to enhance durability and prevent gap losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the blade tip material is improved for high-temperature stability (creep resistance, thermomechanical fatigue), then the blade can operate at higher temperatures, but the oxidation resistance deteriorates
Solution Approach 1:
The patent applies different material properties to different regions of the blade tip. The squealer tip region (facing the housing) is made of oxidation-resistant material (MCrAlY alloy), while other blade tip regions can use materials optimized for mechanical strength and creep resistance. This local differentiation allows the blade to withstand high temperatures in the main body while protecting the oxidation-prone squealer tip region.
Solution Approach 2:
The blade tip is constructed as a composite structure combining two different materials: a nickel-based superalloy for the main blade body (providing high-temperature mechanical stability) and an MCrAlY oxidation-resistant alloy for the squealer tip region (providing oxidation protection). This composite approach allows each material to perform its optimal function without compromising the other.
2Reliability
If conservative design measures are taken (smaller gap, lower combustion temperature, greater cooling), then oxidation damage is reduced, but efficiency decreases due to greater cooling air consumption or power loss
Solution Approach 1:
The invention changes the material parameter (composition and properties) of the blade tip from conventional nickel-based superalloy to an MCrAlY oxidation-resistant alloy. This material parameter change enables the blade tip to resist oxidation without requiring conservative operational parameters (such as reduced combustion temperature or increased cooling air flow), thereby maintaining turbine efficiency while improving durability.
3Strength
If a thick abradable ceramic layer is applied to the ring segment to minimize blade tip damage, then mechanical protection is improved, but the ceramic layer becomes brittle and may fail
Solution Approach 1:
The patent replaces the mechanical ceramic coating system with a metallurgical solution. Instead of applying a thick ceramic layer that relies on mechanical adhesion and is prone to brittleness, the invention uses an MCrAlY alloy that can be metallurgically bonded to the blade tip. This metallurgical bonding provides superior integrity and reliability while maintaining the protective function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly improves the oxidation resistance of the blade tip, reducing material stripping and extending blade lifetime while maintaining efficiency by using MCrAlY alloy and ceramic particles, particularly in the squealer tip region, and enabling complex cooling structures for further protection.
Implementation Method 1
the second material is more resistant to oxidation than the first material... MCrAlY alloys (M represents Co and/or Ni) are advantageously notable for high oxidation resistance
Implementation Method 2
Additive manufacturing methods are particularly suitable for the construction of the blade tip, for example laser application welding, selective laser melting and selective electron beam melting
Implementation Method 3
The second material advantageously has the following chemical composition... This MCrAlY alloy in this composition is notable for particularly high thermal stability, which has an advantageous effect in relation to incision of the blade tip into an abradable coating of the corresponding turbine housing
Data Source
AI summary
A turbine blade for the rotor of a gas turbine, having a blade airfoil, which has a blade airfoil main body with a first material and a blade airfoil tip with a second material, the second material being more resistant to oxidation than the first material. The composition of the second material is graduated at least in subregions. A method for producing the turbine blade includes: providing a main body of a turbine blade airfoil on a construction platform of a device for performing an additive method, the main body having a first material; applying a pulverous second material, which is different from the first material, in a certain amount; fusing the pulverous material by applying a high-energy beam; lowering the construction platform, repeating applying and fusing the pulverous material and of lowering the construction platform as many times as necessary to complete the tip of the blade airfoil.