Al-Zn-Ca Magnesium Sheet Composition for Room-Temperature Forming

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Solution Overview

Problem

The vehicle industry faces challenges in using magnesium alloy sheets due to their limited moldability at room temperature, which hinders their commercialization, and existing methods to improve moldability are complex and costly, such as requiring multiple annealing steps or being difficult to scale for mass production.

Innovation Solution

A magnesium alloy sheet composition of 0.5 to 2.1 wt% Al, 0.5 to 1.5 wt% Zn, 0.1 to 1.0 wt% Ca, with a balance of Mg and inevitable impurities, along with optional Mn, is developed, allowing for improved moldability through controlled component ratios and reduced annealing steps, enabling strip casting and enhanced mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If magnesium alloy sheet is used to reduce vehicle body weight, then weight reduction is achieved, but moldability at room temperature is poor due to HCP structure limitations

Engineering Contradiction:
Improvevehicle body weightVSAvoidmoldability
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the magnesium alloy by precisely controlling the content of Al (0.5-2.0 wt%), Zn (0.5-1.5 wt%), and Ca (0.1-1.0 wt%). This compositional parameter change enables the alloy to achieve excellent room-temperature moldability (Erichsen value ≥4.5mm) while maintaining lightweight properties, resolving the contradiction between weight reduction and manufacturability

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional alloy composition (3 wt% Al, 1 wt% Zn, 1 wt% Ca) is used to improve moldability, then Erichsen value increases, but intermediate annealing must be performed multiple times increasing process cost

Engineering Contradiction:
ImprovemoldabilityVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent optimizes the compositional parameters within specific ranges (Al: 0.5-2.0 wt%, Zn: 0.5-1.5 wt%, Ca: 0.1-1.0 wt%) to achieve a balance between moldability and process simplicity. This parameter optimization allows the alloy to maintain excellent formability (Erichsen ≥4.5mm) while reducing the number of intermediate annealing steps required, thereby lowering process complexity and cost

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If alloy composition is controlled to improve moldability, then room temperature forming becomes possible, but strip casting method cannot be applied and mass production is difficult

Engineering Contradiction:
ImprovemoldabilityVSAvoidmass production capability
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent defines specific compositional parameter ranges (Al: 0.5-2.0 wt%, Zn: 0.5-1.5 wt%, Ca: 0.1-1.0 wt%) that simultaneously satisfy both moldability requirements (Erichsen ≥4.5mm) and strip casting processability. This dual-optimized parameter specification enables the alloy to be both formable at room temperature and suitable for high-speed strip casting production, achieving a balance between quality and productivity

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

This composition achieves excellent moldability and mechanical properties, including an Erichsen value of 4.5 mm or more at room temperature, facilitating mass production with reduced process costs and minimizing defects like edge cracks.

Implementation Method 1

the preparing of the rolled material by rolling the casting material includes intermediate annealing of the rolled material

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentEP3561095B1Method for manufacturing magnesium alloy sheet
Publication Date: 2023.06.14 POSCO HLDG INC
  • EP3561095B1 patent drawingFigure 1
  • EP3561095B1 patent drawingFigure 2
  • EP3561095B1 patent drawingFigure 3

AI summary

An exemplary embodiment of the present invention relates to a magnesium alloy sheet and a manufacturing method thereof. The exemplary embodiment of the present invention provides a magnesium alloy sheet including 0.5 to 2.1 wt% of Al, 0.5 to 1.5 wt% of Zn, 0.1 to 1.0 wt% of Ca, and a balance of Mg and inevitable impurities, with respect to a total of 100 wt% of the magnesium alloy sheet.