Aluminum Alloy Additive Manufacturing for Hot Hardness

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Solution Overview

Problem

Current aluminum alloys used in additive manufacturing, such as 4xxx alloys, exhibit limited mechanical properties at room temperature and poor performance at high temperatures, particularly in selective laser melting (SLM) applications, with Scalmalloy and Addalloy showing high costs and limited hardness.

Innovation Solution

A method for manufacturing aluminum alloy parts using an alloy composition with specific elements like Fe, Cr, Zr, and optional elements like Ti, Hf, Er, and Sc, which are selectively melted and solidified to form layers, followed by heat treatment or hot isostatic pressing to enhance mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional aluminum alloys (4xxx series) are used in additive manufacturing, then the manufacturing process is well-established, but the mechanical properties at room temperature and high temperature are limited

Engineering Contradiction:
Improvemechanical propertiesVSAvoidperformance at high temperature
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of aluminum alloys by introducing specific alloying elements (Fe: 1-10%, Cr: 1-10%, Zr: 0.1-4%, Ti: 0.1-2%, Hf: 0.1-2%) and controlling their concentrations to achieve superior mechanical properties and thermal stability. This parameter change transforms conventional 4xxx series alloys into enhanced compositions that maintain strength at both room temperature and high temperature conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite aluminum alloys by combining base aluminum with multiple alloying elements (Fe, Cr, Zr, Ti, Hf) in specific proportions. This composite approach leverages the synergistic effects of different elements to achieve both high strength at room temperature and maintained performance at elevated temperatures, overcoming the limitations of single-element or conventional multi-element alloys.

Inventive Principle:
Principle #40Composite materials

2Strength

If Scalmalloy or Addalloy are used, then high strength is achieved, but the cost increases significantly

Engineering Contradiction:
ImprovestrengthVSAvoidcost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent achieves high strength properties through optimized composition parameters that are more cost-effective than Scalmalloy or Addalloy. By controlling Fe (1-10%), Cr (1-10%), Zr (0.1-4%), Ti (0.1-2%), and Hf (0.1-2%) within specific ranges, the invention obtains comparable or superior strength to expensive alloys while using more affordable material constituents.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive alloying systems (Scalmalloy, Addalloy) with cheaper alternative compositions that achieve similar performance. The invention uses cost-effective elements like Fe, Cr, Zr, Ti, and Hf in optimized amounts to substitute for more expensive alloying strategies, reducing material costs while maintaining high strength characteristics.

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

3Ease of manufacture

If standard aluminum alloys are used, then manufacturing is straightforward, but hot hardness and thermal stability are insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidhot hardness and thermal stability
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent enhances thermal stability and hot hardness by modifying the chemical composition parameters. The specific ranges of Fe (1-10%), Cr (1-10%), Zr (0.1-4%), Ti (0.1-2%), and Hf (0.1-2%) are optimized to create an alloy that maintains its mechanical properties at elevated temperatures while remaining compatible with standard additive manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite aluminum alloy system that provides both ease of manufacture and superior thermal stability. The multi-element composition (Al-Fe-Cr-Zr-Ti-Hf) leverages the heat-resistant properties of each element to achieve high hot hardness while maintaining manufacturability through established powder production and additive manufacturing techniques.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If conventional aluminum alloys are used in SLM, then processing is simple, but sensitivity to hot cracking is high

Engineering Contradiction:
Improveprocessing simplicityVSAvoidsensitivity to hot cracking
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent reduces hot cracking sensitivity by optimizing the chemical composition parameters. The controlled amounts of Fe (1-10%), Cr (1-10%), Zr (0.1-4%), Ti (0.1-2%), and Hf (0.1-2%) modify the solidification behavior and microstructure of the alloy, reducing susceptibility to hot cracking during selective laser melting while maintaining processing simplicity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of hot cracking into a benefit by carefully controlling the alloying elements to promote beneficial solidification patterns. The specific composition ranges encourage controlled dendrite formation and grain structure development that actually resist cracking, turning a potential failure mode into a strength-enhancing mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 parts with improved hot hardness and thermal stability, offering better mechanical properties compared to prior art alloys, with increased hardness after heat treatment and reduced sensitivity to hot cracking during the SLM process.

Implementation Method 1

each layer being formed by the deposition of a metal, called filler metal, the filler metal being subjected to an energy input so as to melt and to constitute, by solidifying, said layer

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

followed by heat treatment or hot isostatic pressing to enhance mechanical properties

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3860787B1Process for manufacturing an aluminum alloy part
Publication Date: 2024.07.10 C TEC CONSTELLIUM TECH CENT
  • EP3860787B1 patent drawingFigure 1
  • EP3860787B1 patent drawingFigure 2~3

AI summary

The invention relates to a process for manufacturing a part comprising the formation of successive solid metal layers (201...20n) that are stacked on top of one another, each layer describing a pattern defined using a numerical model (M), each layer being formed by the deposition of a metal (25), referred to as solder, the solder being subjected to an input of energy so as to start to melt and to constitute, by solidifying, said layer, wherein the solder takes the form of a powder (25), the exposure of which to an energy beam (32) results in melting followed by solidification so as to form a solid layer (201...20n). The process is characterized in that the solder (25) is an aluminum alloy comprising at least the following alloy elements: - Fe, in a weight fraction of from 1 to 10 %, preferably from 2 to 8 %, more preferably from 2 to 5 %, even more preferably from 2 to 3.5 %; - Cr, in a weight fraction of from 1 to 10 %, preferably from 2 to 7 %, more preferably from 2 to 4 %; - optionally Zr and/or Hf and/or Er and/or Sc and/or Ti, in a weight fraction of up to 4 %, preferably from 0.5 to 4 %, more preferably from 1 to 3 %, even more preferably from 1 to 2 % each, and in a weight fraction of less than or equal to 4 %, preferably less than or equal to 3 %, more preferably less than or equal to 2 % in total; - Si, in a weight fraction of less than or equal to 1 %, preferably less than or equal to 0.5 %. The invention also relates to a part obtained by this process. The alloy used in the additive manufacturing process according to the invention makes it possible to obtain parts having remarkable features.