TiAl Coating via Laser Wire Feed Welding

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Solution Overview

Problem

Laser build-up welding of TiAl alloys faces challenges in achieving homogeneous coatings or structural elements due to demixing of powder components, incomplete melting, and low powder utilization, leading to inconsistent material properties and reduced efficiency.

Innovation Solution

Supplying titanium and aluminum in wire or band form, with controlled laser power and energy density to ensure complete melting and mixing, allowing for the formation of TiAl coatings or structural elements with predefined compositions, including additional alloy elements, and utilizing powder filler wires or bands to achieve 100% material utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If powder mixture is used for laser build-up welding, then coating formation is possible, but demixing of components occurs leading to inhomogeneous material composition

Engineering Contradiction:
Improvecoating material compositionVSAvoidhomogeneity of coating material
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent changes the physical state and form of the coating material from powder to wire/rod form. This parameter change eliminates demixing issues because wires maintain their structural integrity during feeding and melting, ensuring homogeneous mixing of Ti and Al components in the melt pool without separation that occurs with powder mixtures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The laser beam acts as an intermediary that melts both Ti and Al wires simultaneously, creating a controlled melt pool where complete mixing occurs. The laser energy serves as the mediating factor that ensures both components are fully melted and homogenized before solidification, preventing the demixing that occurs with gravity-driven powder feeding.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If powder mixture is used for laser build-up welding, then coating formation is possible, but complete melting of all components cannot be ensured

Engineering Contradiction:
Improvematerial composition controlVSAvoidcomplete melting of powder components
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

Changing from powder to wire/rod form allows for more reliable and complete melting. The wire form factor provides consistent thermal conductivity and melting characteristics, ensuring that the predetermined composition ratio of Ti and Al is fully achieved in the melt pool, unlike powder mixtures where incomplete melting is common.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If powder mixture is used for laser build-up welding, then coating formation is possible, but powder utilization is reduced below 100%

Engineering Contradiction:
Improvecoating build-up efficiencyVSAvoidunused powder quantity
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent changes the material form from powder to wire/rod, which enables 100% utilization of the supplied material. Wires are fed continuously and completely melted in the laser zone, eliminating the waste associated with powder that is not fully utilized or requires post-processing removal.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If TiAl alloys are machined or processed, then components can be manufactured, but the process is complex and expensive

Engineering Contradiction:
Improvecomponent processingVSAvoidmanufacturing process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the manufacturing approach from mechanical machining of brittle TiAl alloys to laser-based additive manufacturing. This parameter change in the processing method enables direct formation of components and coatings without complex machining operations, significantly reducing process complexity and cost while maintaining the desired material properties.

Inventive Principle:
Principle #35Parameter changes

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 enables the formation of homogeneous TiAl coatings or structural elements with precise material composition and high utilization efficiency, reducing the need for complex reworking and minimizing energy and plant technology costs, while maintaining high strength and temperature resistance.

Implementation Method 1

Supplying at least one wire (1) comprising titanium (Ti) and/or a titanium alloy and at least one wire (2) comprising aluminum (Al) and/or an aluminum alloy into a region of influence of at least one laser beam (20) perpendicular to a surface of a substrate (10)

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

The different materials are melted and mixed with one another in this respect due to the thermal input of the laser radiation

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

The melting bath temperature can be maintained so that the melt has a small viscosity so that a good mixing of the individual components can be achieved by the melting bath movement

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentUS10150183B2Method of forming a coating or of three-dimensional structural elements on substrate surfaces, which is/are formed by TiAl, by laser build-up welding
Publication Date: 2018.12.11 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

The invention relates to a method of forming a coating or of three-dimensional structural elements on substrate surfaces which is/are formed by TiAl. Said coating/Said three-dimensional structural elements is/are manufactured by laser build-up welding. The procedure is followed in the method in accordance with the invention that titanium and aluminum are supplied into the region of influence of at least one laser beam in wire and/or band form in a pure or alloyed form in each case as a single wire or a single band. They are melted by the thermal input and in this respect the materials are mixed with one another. The coating or three-dimensional structural elements are thereby formed with TiAl on the substrate surface.