Vertical Casting of Aluminum Alloys for Monolithic Structural Elements

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Solution Overview

Problem

Current manufacturing processes for wrought monolithic structural elements with variable mechanical properties are limited in their ability to achieve significant variations in mechanical properties along the length or width of the part, and existing methods often require complex assembly techniques or are difficult to scale for industrial production in aeronautical construction.

Innovation Solution

A vertical casting process that involves preparing and casting two aluminum-based alloys with different compositions in succession without interrupting the flow of liquid metal, creating a solid intermediate product with a concentration gradient in the casting direction, which can be rolled, extruded, or forged to produce bi-functional or multi-functional structural elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional assembly techniques (bolting, riveting, welding) are used to join parts with different properties, then bi-functional or multifunctional structural parts can be obtained, but the complexity of the device and potential galvanic corrosion increase

Engineering Contradiction:
Improvebi-functional or multifunctional capabilityVSAvoidassembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple alloys into a single monolithic structure through sequential casting, eliminating the need for separate parts and assembly operations. The first and second alloys are cast in sequence to form a unified structural element with spatially varying properties, merging what would traditionally require multiple assembled components into one integrated piece.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite structure by incorporating spatially separated regions of different aluminum alloys within a single monolithic element. This composite approach allows different alloy compositions to provide different functions (e.g., corrosion resistance in one region, structural strength in another) while maintaining a unified structure without traditional joints.

Inventive Principle:
Principle #40Composite materials

2Reliability

If clad sheets with alloy coatings are used for corrosion protection or weldability, then protection or easy welding is achieved, but the functional variation is limited to thickness direction only

Engineering Contradiction:
Improvecorrosion protectionVSAvoidfunctional variation capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent extends functional variation from the thickness direction (as in clad sheets) to the length and width directions by casting alloys in sequential layers that extend across the surface area. This allows different alloy compositions to be distributed spatially across multiple dimensions, enabling functional gradients along the length and width of the structural element, not just through the thickness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent applies local quality by creating regions with different alloy compositions at specific locations within the monolithic structure. Each cast region can be tailored with specific alloying elements to provide localized properties such as corrosion resistance, weldability, or structural strength where needed, rather than applying a uniform coating across the entire surface.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If different tempering treatments are applied to different ends of a single alloy product, then small parts with varied properties can be obtained, but the amplitude of mechanical property variation is limited and industrial scaling is difficult

Engineering Contradiction:
Improvespatial variation of mechanical propertiesVSAvoidindustrial scalability
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by incorporating the desired compositional variation directly into the casting process itself, rather than requiring subsequent tempering or heat treatment operations. The spatial distribution of alloying elements is established during casting, allowing different regions to have inherently different properties from the start, which simplifies later processing and enables industrial scaling.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical composition parameter during the casting process by sequentially adding different alloying elements to create regions with distinct compositions. This fundamental change in material composition, rather than relying on post-processing heat treatments, enables greater amplitude of property variation and facilitates industrial production through a more scalable casting-based approach.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If fixed or mobile partitions are used during casting to separate alloys, then monolithic parts with multiple alloys can be manufactured, but the partitions add complexity and may interfere with continuous casting flow

Engineering Contradiction:
Improvemulti-alloy monolithic structureVSAvoidpartition system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the partition concept entirely from the casting system, replacing it with a sequential casting approach where alloys are deposited in successive layers without any physical separators. This eliminates the complexity of partition systems while maintaining the ability to produce monolithic multi-alloy structures through direct sequential solidification of different alloy compositions.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This process enables the production of structural elements with variable mechanical properties along the length or width, suitable for aeronautical applications, by creating a seamless transition between alloys, allowing for the production of large, high-quality parts with enhanced mechanical characteristics.

Implementation Method 1

The flow of liquid metal is not interrupted during the transition from casting the first alloy to casting the second alloy

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP1965936B1Process for manufacturing semi-finished products comprising two aluminium-based alloys
Publication Date: 2020.04.15 CONSTELLIUM ISSOIRE
  • EP1965936B1 patent drawingFigure 1
  • EP1965936B1 patent drawingFigure 2
  • EP1965936B1 patent drawingFigure 3

AI summary

The invention relates to a process for the vertical casting of an intermediate product, comprising step (a) of preparing at least two aluminium-based alloys, especially a first alloy of composition P and a second alloy of composition T; step (b) of casting the first alloy of composition P to a desired height HP; step (c) of casting an additional desired height HT of the second alloy of composition T. The invention makes it possible to manufacture monolithic structural elements having usage properties that vary in at least one direction, and especially bifunctional or multifunctional structural elements for fulfilling at least two functions that are conventionally fulfilled by two different parts.