Ni-Base Superalloy Composition Using Eutectics to Suppress SLM Hot Cracking
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Solution Overview
Problem
Ni-base superalloys with high γ'(Gamma Prime) content are susceptible to hot cracking during Selective Laser Melting (SLM), limiting their industrialization, especially in high-temperature applications like the gas turbine industry, as existing solutions either fail to completely prevent cracking or are economically unviable.
Innovation Solution
A Ni-base superalloy composition with increased amounts of elements forming low-melting eutectics, particularly Hf, is used, along with an SLM process performed under a protective atmosphere with low O2 content, to enhance the backfilling of emerging cracks and reduce hot cracking susceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high γ' content is used to improve high-temperature strength, then strength at temperature is improved, but hot cracking susceptibility increases
Solution Approach 1:
The invention modifies the chemical composition parameters by increasing specific alloying elements (Co: 8-12 wt.%, Cr: 7-10 wt.%, Al: 4-6 wt.%, Ti: 2-3 wt.%, Hf: 1-2 wt.%, Ta: 2-3 wt.%, W: 8-10 wt.%, Mo: 0.5-1.5 wt.%) to change the solidification behavior and reduce hot cracking while maintaining high γ' content (15-25 vol.%) for strength
Solution Approach 2:
The invention creates a composite microstructure consisting of γ matrix with dispersed γ' precipitates, where the controlled composition enables a eutectic-like solidification mode that combines the strength benefits of high γ' content with improved crack resistance through optimized phase distribution
2Ease of manufacture
If standard composition superalloys are used for SLM, then manufacturing simplicity is maintained, but extensive hot cracking occurs
Solution Approach 1:
The invention systematically adjusts multiple compositional parameters simultaneously (increasing Co, Cr, Al, Hf, Ta, W while controlling Ti and Mo) to achieve a eutectic-like solidification mode that reduces hot cracking, while maintaining compatibility with standard SLM manufacturing processes
3Reliability
If existing solutions to reduce hot cracking are implemented, then cracking susceptibility decreases, but economic viability is compromised
Solution Approach 1:
The invention achieves crack reduction through optimized compositional parameters within commercially reasonable ranges, avoiding excessive alloying additions that would significantly increase material cost while still achieving the eutectic-like solidification mode necessary for crack resistance
Solution Approach 2:
The invention strategically distributes specific alloying elements (particularly Hf, Ta, and W) to control solidification behavior and eutectic formation at critical locations during cooling, maximizing crack resistance while minimizing overall material cost
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 approach significantly reduces hot cracking during SLM processing, enabling the production of crack-free parts with improved surface quality and mechanical properties, while avoiding the limitations of high temperatures and oxidation issues in existing methods.
Implementation Method 1
Selective laser melting of γ'(Gamma Prime)Ni3(AI,Ti) hardened Ni-base superalloys
Implementation Method 2
laser melting (SLM)... to melt and fuse the powder particles
Implementation Method 3
elements forming low-melting eutectics, particularly Hf... to enhance the backfilling of emerging cracks
Implementation Method 4
enhance the backfilling of emerging cracks... by the liquid eutectic phases
Implementation Method 5
SLM process is performed under protective atmosphere with low O2 content... to prevent binding of free Hf in oxides
Data Source
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AI summary
The invention relates to a Ni-base superalloy composition to be used for powder-based additive manufacturing (AM) technology, such as selective laser melting (SLM) or electron beam melting (EBM). The cracking susceptibility during an AM process is considerably reduced by controlling the amount of elements, especially Hf, that form low-melting eutectics.