Nickel Superalloy Composition for Crack Reduction in Additive Manufacturing
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Solution Overview
Problem
Additive manufacturing of nickel superalloys like IN-939 often results in micro-cracks and poor creep ductility, which are unsuitable for critical components in turbines.
Innovation Solution
A nickel alloy with a boron content of less than 40 ppmw, comprising 40-55 wt.% Ni, 20-25 wt.% Cr, 5-25 wt.% Co, and 1.5-5 wt.% Ti, is used, along with a process involving selective laser sintering or melting, and optionally heat treatment, to minimize micro-cracks and enhance creep ductility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional IN-939 superalloy is used for additive manufacturing, then the material can be processed layer-by-layer, but micro-cracks form and creep ductility is poor
Solution Approach 1:
The patent modifies the chemical composition parameters of the IN-939 superalloy by controlling the content of alloying elements (Ni: 40-55 wt.%, Cr: 20-25 wt.%, Co: 5-25 wt.%, Ti: 1.5-5 wt.%, B: <40 ppmw) to eliminate micro-cracks and improve creep ductility during additive manufacturing
Solution Approach 2:
The patent applies local quality control by specifically managing the boron content at very low levels (<40 ppmw) in certain regions of the alloy composition to prevent micro-crack formation, while maintaining other properties for creep resistance
2Productivity
If casting is used to manufacture superalloy components, then bulk material can be produced, but post-processing is required and production is time-consuming
Solution Approach 1:
The patent replaces traditional casting and mechanical post-processing with additive manufacturing technology, where components are built layer-by-layer from powder material, eliminating the need for time-consuming post-processing operations while maintaining high productivity
3Strength
If standard IN-939 alloy composition is used, then oxidation resistance and creep strength are achieved, but creep ductility is insufficient without complex heat treatment
Solution Approach 1:
The patent changes the chemical composition parameters of the alloy, specifically controlling the content of Ni (40-55 wt.%), Cr (20-25 wt.%), Co (5-25 wt.%), Ti (1.5-5 wt.%), and B (<40 ppmw), to achieve sufficient creep ductility without requiring complex multi-step heat treatment 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 alloy significantly reduces micro-cracks and improves creep ductility, making it suitable for high-performance components in turbines.
Implementation Method 1
selective laser sintering or selective laser melting
Implementation Method 2
selective laser sintering or selective laser melting
Implementation Method 3
layer-wise solidification of metal powder layers
Data Source
AI summary
Nickel alloys in powder form comprising at least 40 wt.-% Ni, about 20.0 to 25.0 wt.-% Cr, about 5.0 to 25.0 wt.-% Co and about 1.5 to 5.0 wt.-% Ti, which have a content of B in an amount of less than 40 ppmw, are disclosed. Corresponding alloys have the advantage of providing minimal or no micro-cracks as well as an improved ductility in creep conditions compared to similar alloys having a higher content of B, when the alloys are processed by additive manufacturing to prepare three-dimensional objects.