Co-Based Alloy Composition for Additive Manufacturing Strength

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Solution Overview

Problem

Additive manufacturing of cobalt-based alloys results in products with significantly reduced mechanical strength compared to conventionally forged Ni-based and Co-based alloys, lacking sufficient high-temperature strength and yield improvement.

Innovation Solution

A cobalt-based alloy product with specific composition (0.001 mass% ≤ C < 0.100 mass%, 9.0 mass% ≤ Cr < 20.0 mass%, 2.0 mass% ≤ Al < 5.0 mass%, 13.0 mass% ≤ W < 20.0 mass%, 39.0 mass% ≤ Ni < 55.0 mass%) is produced using wire additive manufacturing, followed by solution heat treatment and aging heat treatment to form segregated cells and γ' phase precipitation, enhancing high-temperature strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wire additive manufacturing is used to produce Co-based alloy products, then productivity and yield are improved, but mechanical strength is significantly reduced

Engineering Contradiction:
ImproveyieldVSAvoidmechanical strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the alloy composition parameters (C: 0.001-0.100 mass%, Cr: 9.0-20.0 mass%, Al: 2.0-5.0 mass%, W: 13.0-20.0 mass%, Ni: 39.0-55.0 mass%) to achieve both high productivity through additive manufacturing and high mechanical strength. This compositional optimization enables the additive manufactured parts to reach tensile strength of 1000 MPa or more and elongation of 10% or more, resolving the contradiction between manufacturing efficiency and material strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite microstructure consisting of γ phase matrix with precipitated γ' phase (Co3(Al,W)) and carbides. This composite structure at the micro level provides both the ductility needed for additive manufacturing success and the strength required for high-temperature applications, effectively resolving the strength-yield contradiction.

Inventive Principle:
Principle #40Composite materials

2Temperature

If conventional Ni-based alloy forged materials are used, then high-temperature strength is maintained, but productivity and yield are reduced

Engineering Contradiction:
Improvehigh-temperature strengthVSAvoidyield
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent changes the alloy composition parameters to create a Co-based alloy system with optimized content ranges that provide high-temperature strength comparable to Ni-based alloys while enabling additive manufacturing. The specific composition (particularly Cr: 9.0-20.0 mass%, W: 13.0-20.0 mass%, Al: 2.0-5.0 mass%) ensures high-temperature performance while the additive manufacturing process improves productivity and yield.

Inventive Principle:
Principle #35Parameter changes

3Shape

If additive manufacturing is used for Co-based alloys, then complex shapes are achieved, but mechanical strength and high-temperature strength are reduced

Engineering Contradiction:
Improvecomplex shapesVSAvoidmechanical strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent optimizes composition parameters (C: 0.001-0.100 mass%, Cr: 9.0-20.0 mass%, Al: 2.0-5.0 mass%, W: 13.0-20.0 mass%, Ni: 39.0-55.0 mass%) to compensate for the microstructural defects inherent in additive manufacturing of complex shapes. This compositional control ensures that even complex geometries achieve tensile strength of 1000 MPa or more and elongation of 10% or more.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite microstructure with γ phase matrix, γ' phase precipitates, and carbide distributions that provide strength despite the complex build geometry. This micro-composite structure resolves the contradiction between shape complexity and mechanical strength.

Inventive Principle:
Principle #40Composite materials

4Productivity

If additive manufacturing is used for Co-based alloys, then productivity is improved, but high-temperature strength is reduced

Engineering Contradiction:
ImproveyieldVSAvoidhigh-temperature strength
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent optimizes composition parameters (Cr: 9.0-20.0 mass%, W: 13.0-20.0 mass%, Al: 2.0-5.0 mass%, C: 0.001-0.100 mass%) to ensure high-temperature strength is maintained despite the additive manufacturing process. This compositional control enables high-temperature strength comparable to conventional forged materials while retaining the productivity benefits of additive manufacturing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite microstructure with heat-resistant γ' phase precipitates and carbides that maintain strength at high temperatures, resolving the contradiction between productivity improvement through additive manufacturing and high-temperature strength requirements.

Inventive Principle:
Principle #40Composite 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

The method produces a Co-based alloy product with high-temperature strength comparable to or exceeding conventional forged materials, while improving yield and reducing processing waste, thus addressing the strength and yield limitations of additive manufactured alloys.

Implementation Method 1

followed by solution heat treatment and aging heat treatment to form segregated cells and γ' phase precipitation, enhancing high-temperature strength

Methodology Applied
Scientific EffectPhase precipitation: Precipitation

Implementation Method 2

followed by solution heat treatment and aging heat treatment to form segregated cells and γ' phase precipitation

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP4159360A1Cobalt-based alloy product and method for producing cobalt-based alloy product
Publication Date: 2023.04.05 DAIDO STEEL CO LTD
  • EP4159360A1 patent drawingFigure 1
  • EP4159360A1 patent drawingFigure 2
  • EP4159360A1 patent drawingFigure 3~4

AI summary

The present invention relates to a Co-based alloy product including a polycrystal of a Co-based alloy, the Co-based alloy including: 0.001 mass% ≤ C &lt;0.100 mass%; 9.0 mass% ≤ Cr &lt; 20.0 mass%; 2.0 mass% ≤ Al &lt; 5.0 mass%; 13.0 mass% ≤ W &lt; 20.0 mass%; and 39.0 mass% ≤ Ni &lt; 55.0 mass%, with the balance being Co and unavoidable impurities, in which the Co-based alloy product comprises segregated cells formed inside a crystal grain of the polycrystal, the segregated cells have an average size of 1 µm or larger and 100 µm or smaller, and the segregated cells contain Al and Cr, and a method for producing the Co-based alloy product.