Titanium Leading Edge Reinforcement via Diffusion Bonding

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Solution Overview

Problem

The current manufacturing processes for titanium leading edges in aeronautics are complex, costly, and do not adequately address the need for improved erosion resistance, especially for complex shapes.

Innovation Solution

A method involving stamping and diffusion bonding of titanium sheets around a core, with an erosion-resistant insert made of alloys like Ti5553, Ti10-2-3, Ti17, TiAl, or Ti2AlNb, which is integrated during the hot isostatic pressing process to enhance the leading edge's erosion resistance without additional operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If hot forming operations are used to manufacture titanium leading edges, then the leading edge can be formed to the required shape, but the manufacturing process becomes complex and costly requiring specialized tooling and extensive machining

Engineering Contradiction:
Improveleading edge shapeVSAvoidmanufacturing process complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent changes the temperature parameter by using cold forming instead of hot forming, eliminating the need for high-temperature tooling and reducing manufacturing complexity while maintaining the required leading edge shape

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The manufacturing process is segmented into distinct stages: cold forming of sheets, assembly around a core, and diffusion bonding. This segmentation allows each operation to be optimized independently and reduces overall process complexity

Inventive Principle:
Principle #1Segmentation

2Weight of moving object

If titanium sheets are made thin to reduce weight, then weight is reduced, but erosion resistance is compromised

Engineering Contradiction:
Improveleading edge weightVSAvoiderosion resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent creates a composite structure by diffusion bonding titanium sheets to a nickel-based alloy layer. The thin titanium sheets provide lightweight structural support while the nickel-based alloy layer provides erosion resistance, resolving the contradiction between weight reduction and erosion protection

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The nickel-based alloy layer is applied locally at the leading edge where erosion occurs most severely, rather than making the entire structure thicker. This provides targeted erosion protection while maintaining overall weight efficiency

Inventive Principle:
Principle #3Local quality

3Reliability

If a nickel-based alloy reinforcement is used for complex leading edge shapes, then erosion resistance is improved, but manufacturing becomes very complicated and expensive

Engineering Contradiction:
Improveerosion resistanceVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The nickel-based alloy layer is prepared in advance as a separate component with the required complex shape, then bonded to the titanium sheets. This preliminary preparation simplifies the overall manufacturing process compared to attempting to form complex nickel alloy reinforcements from scratch

Inventive Principle:
Principle #10Preliminary action

4Strength

If the SPFDB process is used to assemble sheets, then weight is reduced and mechanical strength is improved, but control of internal cavity shape and sheet connection at cavity end becomes difficult

Engineering Contradiction:
Improvemechanical strengthVSAvoidcavity shape control
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A core is introduced as an intermediary tool during the diffusion bonding process. The core defines and maintains the precise internal cavity shape while the sheets are bonded around it, solving the cavity shape control problem without compromising the strength benefits of diffusion bonding

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This method simplifies and cost-reduces the production of titanium reinforcements while significantly improving the erosion resistance of leading edges, ensuring better durability and service life for turbine engine blades.

Implementation Method 1

welding them together by diffusion

Methodology Applied
Scientific EffectDiffusion welding: Diffusion Welding

Implementation Method 2

a core onto which titanium sheets are welded together and applied around the core by hot isostatic compression

Methodology Applied
Scientific EffectHot isostatic pressing: Hot Isostatic Pressing

Data Source

PatentEP2838692B1Method for creating a metal reinforcement piece for protecting a leading edge or a trailing edge of a composite blade and respective metal reinforment piece
Publication Date: 2019.07.03 SAFRAN AIRCRAFT ENGINES SAS
  • EP2838692B1 patent drawingFigure 1~3
  • EP2838692B1 patent drawingFigure 4~6

AI summary

Method for producing a metal reinforcement for protecting a leading edge of a compressor blade of composite, characterized in that the method involves the steps of: - creating a core (3) that has the shape of the internal cavity of the reinforcement, - creating an insert (7) made of an alloy of a hardness greater than that of the reinforcement, - shaping sheet metal by stamping with the creation, upstream of said core, of a cavity (6) between the metal sheets which cavity is able to accept said insert, - positioning said sheets around said core (3) with the insert (7) placed in said cavity (6) and securing the assembly together, - the creation of a vacuum and the closing of the assembly by welding, - consolidation by hot isostatic pressing, - cutting of the assembly to extract the core (3) and separate the reinforcement, - creating the external profile of the reinforcement by a final machining operation that reveals the material of the insert (7). Figure for the abstract: figure