Additive Manufacturing Grain Size Control
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Solution Overview
Problem
Existing additive manufacturing methods, such as Selective Laser Melting (SLM), produce components with homogeneous microstructures that are optimal for tensile and Low Cycle Fatigue strength but lack high-temperature properties due to small grain size, and current recrystallization techniques either uniformly change the microstructure or allow limited grain size variation, forcing a trade-off between creep and LCF properties.
Innovation Solution
A method that defines different component volumes within a part and applies distinct process parameters during SLM to control recrystallization behavior, followed by a heat treatment to achieve localized variations in grain size, optimizing microstructure for specific load types, such as creep or LCF, by selecting appropriate process parameters like weld pool size, energy input, and scanning strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform process parameters are used during additive manufacturing, then manufacturing simplicity is maintained, but microstructure cannot be optimized for different load types
Solution Approach 1:
The patent implements local quality by assigning different process parameters to different component volumes based on their specific load requirements. This allows the microstructure to be optimized locally for creep, LCF, or tensile properties without complicating the overall manufacturing process, as the parameter variation is integrated into the additive manufacturing workflow.
2Manufacturing precision
If direct grain size control during SLM process is attempted, then grain size variation is achieved, but device complexity increases due to multi-laser systems
Solution Approach 1:
The patent achieves grain size control by changing process parameters (laser power, scan speed, hatch distance, layer thickness) within a single laser system rather than using multiple lasers with different beam characteristics. This approach maintains manufacturing simplicity while achieving the desired grain size variation across different component volumes.
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 approach enables the creation of components with tailored grain sizes and microstructures, enhancing both creep and LCF properties without compromising high-temperature performance, specifically benefiting gas turbines and other thermomechanical applications.
Implementation Method 1
manufacturing said component by means of said additive manufacturing process according to said data set
Implementation Method 2
the grain size is controlled by controlling the cooling rate of the melt pool within the additive manufacturing process
Implementation Method 3
subjecting said manufactured component to a heat treatment in order to change the microstructure of said manufactured component
Implementation Method 4
a recrystallization heat treatment (HT) has been developed for such additively manufactured superalloys, which results in an almost complete crystallographic isotropy and in a considerably larger grain size
Data Source
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AI summary
The invention relates to a method for manufacturing a component (10), especially for gas turbines and other thermo machinery, comprising the steps of: Providing a data set defining said component (10) for being used in an additive manufacturing process; manufacturing said component (10) by means of said additive manufacturing process according to said data set; and subjecting said manufactured component (10) to a heat treatment (HT) in order to change the microstructure of said manufactured component (10). The properties of the component are improved in that: at least two different component volumes (CA1-CA3) are defined within said component (10) prior to the manufacturing step; at least two different process parameters (A, B) are chosen for said additive manufacturing process, which process parameters (A, B) result in different driving forces for a recrystallization and therefore a different recrystallization behavior in the material of said component (10); and said additive manufacturing process is executed with one of said at least two process parameters (A, B) being used during manufacturing a first of said at least two component volumes (CA1-CA3), resulting in a first recrystallization behavior in said first component volume, and with the other of said at least two process parameters (A, B) being used during manufacturing a second of said at least two component volumes (CA1-CA7), resulting in a second recrystallization behavior different from said first recrystallization behavior, in said second component volume; and said manufactured component (10, 10') is subjected to a heat treatment (HT), with a holding temperature (T_HT), wherein the holding temperature (T_HT) lies above a recrystallization temperature of at least one of said at least two component volumes.