Nickel-Based Superalloy Composition for Crack-Resistant Additive Manufacturing
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Solution Overview
Problem
Nickel-based superalloys used in high-temperature applications, such as aircraft engine turbines, face challenges with microcracking and macrocracking during additive manufacturing and heat treatment, which affect their mechanical properties and reliability.
Innovation Solution
A nickel-based superalloy composition with reduced Zr and Si content, increased Mo and W content, and decreased Ti, Nb, and C content is developed to slow down the precipitation of the γ' phase and strengthen the austenitic matrix, thereby reducing cracking and maintaining mechanical characteristics equivalent to Inconel 738 LC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the γ' phase content is increased to improve high-temperature performance, then mechanical resistance at high temperatures is improved, but microcracking and macrocracking occur during additive manufacturing and heat treatment
Solution Approach 1:
The patent modifies the chemical composition parameters of the nickel-based superalloy, specifically adjusting the content of alloying elements (Cr: 15-18%, Co: 8-11%, Mo: 0.75-2.2%, W: 1.8-3%, Al: 3-4%, Ti: 3-4%, Nb: 0.5-2%, Ta: 1-3%, C: 0.1-0.2%, B: 0.01-0.05%, Zr: 0.01-0.2%) to optimize the balance between γ' phase precipitation and cracking resistance. This compositional parameter change allows the alloy to maintain high γ' content for strength while reducing susceptibility to microcracking during additive manufacturing and macrocracking during heat treatment.
2Strength
If Al content is increased to increase γ' precipitates and improve hardness, then mechanical strength is improved, but cracking tendency increases during laser additive manufacturing
Solution Approach 1:
The patent optimizes the Al content within a specific range (3-4%) and balances it with other alloying elements (Ti, Nb, Ta, C, B) to control γ' phase precipitation kinetics. This balanced compositional approach allows the alloy to develop sufficient γ' precipitates for hardness and strength while controlling the precipitation rate and distribution to minimize cracking during laser additive manufacturing processes.
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 modified composition significantly reduces microcracking and macrocracking, enhancing the alloy's resistance to creep and corrosion while maintaining mechanical properties and operating temperature stability up to 1050-1100°C.
Implementation Method 1
slow down the precipitation of the γ' phase
Implementation Method 2
the addition of molybdenum and tungsten, which are heavy elements mainly present in the austenitic matrix, will on the one hand strengthen the matrix
Data Source
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AI summary
The present invention relates to a nickel-based superalloy having a high γ'-phase content intended for the manufacture of parts by additive manufacturing followed by a heat treatment, characterized in that its composition comprises in percentages by weight of the total composition: Cr: 15.5 - 16.5; Co: 7.7 - 11; Mo + W: 5.5 - 7.5; Al: 2.9 - 4.3; Ti: 2.6 - 3.2; Ta: 1.5 - 2.2; Nb: 0.3 - 1.1; C: 0.01 - 0.13; B: 0.0005 - 0.015; Zr: ≤ 0.01; Hf: 0.0001 - 0.5; Si: ≤ 0.06; Ni: balance and unavoidable impurities. The invention also relates to a method for producing powder and turbine parts made of a superalloy.