Nitrided Complex Concentrated Alloy Additive Manufacturing

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Solution Overview

Problem

Current methods for structural hardening of complex concentrated alloys are restrictive and pose safety risks due to the use of nanometric particles, limiting their industrialization and effectiveness in achieving high tensile strength and ductility.

Innovation Solution

A nitrided alloy with a crystalline matrix and dispersed nitrided precipitates is developed, where each base metal is present in a specific atomic percentage range, and the nitrided precipitates are coherent or semi-coherent with the matrix, enhancing yield strength, breaking stress, and elongation at break, while being easier to manufacture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If nanometric particles are introduced into the alloy matrix for structural hardening, then tensile strength increases, but safety risks and manufacturing difficulty increase due to nanometric handling hazards

Engineering Contradiction:
Improvetensile strengthVSAvoidsafety risks from nanometric particles
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention changes the size parameter of the hardening phase from nanometric scale to micrometric scale (1-50 micrometers), eliminating safety hazards associated with nanometric particle handling while preserving the structural hardening effect through controlled precipitation of nitride phases

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces expensive and hazardous nanometric particles with readily available nitride-forming elements (Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) that can be handled in bulk form, eliminating the need for specialized nanometric material handling while achieving the same hardening effect

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Strength

If nanometric particles are introduced into the alloy matrix for structural hardening, then tensile strength increases, but manufacturing complexity and industrialization difficulty increase

Engineering Contradiction:
Improvetensile strengthVSAvoidmanufacturing difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The invention combines the alloying element addition step with the structural hardening mechanism by selecting elements that form nitride precipitates during conventional processing, merging two separate operations (adding hard particles and alloying) into a single integrated process

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The alloying elements (Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) serve dual functions: they are standard alloying components for achieving desired bulk properties, and they simultaneously provide the nitride-forming capacity for structural hardening, eliminating the need for separate hardening agent addition

Inventive Principle:
Principle #25Self-service

3Strength

If the alloy composition is adapted for phase transformation hardening, then tensile strength increases, but the number of suitable alloy compositions is restricted

Engineering Contradiction:
Improvetensile strengthVSAvoidnumber of suitable alloy compositions
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention changes the hardening mechanism from phase transformation (TRIP/TWIP) to precipitation hardening through nitride formation, which is applicable to a broader range of alloy compositions including all elements that form stable nitrides, thereby increasing compositional versatility

Inventive Principle:
Principle #35Parameter changes

4Strength

If interstitial elements are inserted into the crystal lattice for structural hardening, then tensile strength increases, but the alloy composition options are limited to specific elements

Engineering Contradiction:
Improvetensile strengthVSAvoidalloy composition options
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention changes the hardening mechanism from interstitial solid solution strengthening to precipitation hardening through nitride formation, allowing substitutional alloying elements (Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) to provide both bulk properties and hardening capacity, significantly expanding composition options

Inventive Principle:
Principle #35Parameter changes

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 nitrided alloy exhibits significantly improved yield strength, breaking stress, and elongation at break, with nitrided precipitates representing a small fraction of the alloy's mass, providing enhanced mechanical properties without the safety concerns of nanometric particles.

Implementation Method 1

The nanoparticles trap the dislocations by Orawan mechanism, limiting their movement and thus increasing the breaking stress of the material.

Methodology Applied
Scientific EffectOrawan mechanism:

Implementation Method 2

The alloy passes for example from a cubic structure with centered faces towards a compact hexagonal structure. The phase change is accompanied by a variation of internal energy which results in a structural hardening of the material.

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Implementation Method 3

A nitrided alloy with structural hardening comprising: a crystalline matrix in a complex concentrated alloy comprising at least one nitridogenic base metal, and nitrided precipitates, dispersed in the matrix, in a metal nitride.

Methodology Applied
Scientific EffectPrecipitation hardening: Precipitation Hardening

Data Source

PatentEP3747573A1Method for additive manufacturing of a part made of a cca nitride alloy
Publication Date: 2020.12.09 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3747573A1 patent drawingFigure 1~3
  • EP3747573A1 patent drawingFigure 4~6
  • EP3747573A1 patent drawingFigure 7~8

AI summary

A process for manufacturing a metallurgical product comprising, for more than 90.0% of its mass, a structurally hardening nitrided alloy comprising: - a crystalline matrix in a complex concentrated alloy comprising at least one nitrurigenic base metal, and - nitrided precipitates, dispersed in the matrix, in a metallic nitride, the process comprising: i') the supply of a starting powder comprising, or even being made up of, particles containing the complex concentrated alloy, and ii') the shaping of the metallurgical product by an additive manufacturing technique, from the starting powder, the starting powder comprising, or even being made up of, particles formed from the nitrided alloy and/or the shaping in step ii') being carried out within a non-oxidizing atmosphere formed from a reactive gas containing nitrogen.