3D Superalloy Turbine Blade Build-Up With Tailored SLM Microstructure
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Solution Overview
Problem
Conventional build-up welding techniques, such as TIG and LMF, struggle with micro-cracking and are inefficient for gamma-prime strengthened nickel-base superalloys with high Al and Ti content, limiting their use in turbine components due to cracking mechanisms like solidification, liquation, and strainage cracking, and requiring lengthy and costly reconditioning processes.
Innovation Solution
Selective Laser Melting (SLM) is used to build up turbine blade crowns with tailored porosity and secondary phase particles, allowing for the processing of non-castable materials like IN738LC, reducing cracking sensitivity and incorporating efficient cooling structures, thereby overcoming material limitations and fabrication complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional build-up welding techniques (TIG or LMF) are used on gamma-prime strengthened nickel-base superalloys with high Al and Ti content, then the process is simple and equipment is readily available, but micro-cracking occurs and the material cannot be processed
Solution Approach 1:
The patent replaces conventional mechanical welding processes (TIG, LMF) with selective laser melting (SLM), a thermal additive manufacturing process. This substitution eliminates the cracking mechanisms associated with conventional welding by using controlled laser heating and rapid cooling cycles that prevent dendrite formation, liquation cracking, and strainage cracking while building material layer-by-layer
Solution Approach 2:
The patent changes the processing parameters from conventional welding conditions to SLM-specific parameters including laser power, scan speed, hatch spacing, and layer thickness. These parameter changes enable precise thermal control that avoids the temperature ranges causing cracking while maintaining material properties, allowing processing of high Al+Ti content superalloys that are otherwise unweldable
2Productivity
If conventional build-up welding is used for turbine blade reconditioning, then existing equipment can be utilized, but the process takes a long time and requires many process steps
Solution Approach 1:
The patent merges multiple separate reconditioning operations (material build-up, cooling channel fabrication, surface finishing) into a single selective laser melting process. The SLM process can simultaneously deposit material and form complex internal cooling channel geometries in one continuous operation, eliminating sequential process steps and reducing overall reconditioning time
Solution Approach 2:
The selective laser melting process serves multiple functions: it acts as a welding alternative for material build-up, a machining tool for creating cooling channels, and a surface treatment method. This multi-functionality consolidates what would traditionally require multiple specialized processes into one universal additive manufacturing operation
3Strength
If high Al and Ti content nickel-base superalloys are used for high temperature strength and oxidation resistance, then material properties are improved, but the material becomes difficult to weld and process
Solution Approach 1:
The patent replaces conventional mechanical welding with selective laser melting, enabling the processing of high Al+Ti content superalloys (such as IN738LC, MarM-247, CM-247LC) that have excellent high-temperature strength and oxidation resistance but are traditionally unweldable due to their high gamma-prime content (>25 Vol.-%) and susceptibility to cracking
Solution Approach 2:
The patent modifies the processing approach by using SLM parameters (laser power density, scan speed, layer thickness) that are specifically optimized for high-strength nickel-base superalloys. These parameter changes enable the fabrication of components from materials with superior high-temperature properties while avoiding the cracking issues that plague conventional welding of these same materials
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
SLM minimizes porosity and cracking, enhances material properties, reduces wear and thermal loading, and integrates complex cooling features in a single process, improving the efficiency and longevity of turbine blades by enabling the use of high-strength, oxidation-resistant materials.
Implementation Method 1
Selective Laser Melting (SLM) is used to build up turbine blade crowns
Implementation Method 2
Selective Laser Melting (SLM) process... layer by layer melting and bonding of metal powder
Implementation Method 3
Selective Laser Melting (SLM)... layer by layer melting and bonding of metal powder
Data Source
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AI summary
The invention relates to a method for producing a three-dimensional article or at least a part of such an article made of a gamma prime (γ') precipitation hardened nickel base superalloy with a high volume fraction (>25 %) of gamma-prima phase which is a difficult to weld superalloy, or made of a cobalt base superalloy, or of a non-castable or difficult to machine metal material by means of selective laser melting (SLM), in which the article is produced by melting of layerwise deposited metal powder with a laser beam characterized in that the SLM processing parameters are selectively adjusted to locally tailor the microstructure and/or porosity of the produced article or a part of the article and therefore to optimize desired properties of the finalized article/part of the article.