Magnesium Alloy Sheet Composition for Room-Temperature Moldability
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Solution Overview
Problem
Magnesium alloy sheets face challenges in moldability at room temperature and anisotropy due to their hexagonal close-packed structure, limiting their deformation and commercial viability in applications like the vehicle industry, where existing methods for improving moldability are either difficult to implement or result in cracking during deformation.
Innovation Solution
A magnesium alloy sheet composition of 0.5 to 3.5 wt% Al, 0.5 to 1.5 wt% Zn, 0.1 to 1.0 wt% Ca, 0.01 to 1.0 wt% Mn, with a remainder of Mg, and inevitable impurities, is developed, along with a manufacturing method involving cumulative reduction ratios greater than 86% through homogenization, heat-treatment, rolling, and annealing to control crystal grain size and disperse secondary phases, enhancing moldability and reducing anisotropy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If magnesium alloy sheet is used at room temperature, then weight reduction is achieved, but moldability is poor due to HCP structure limiting deformation
Solution Approach 1:
The patent applies parameter changes by controlling the cumulative reduction ratio during rolling to be 80-95%, which fundamentally alters the deformation behavior of the magnesium alloy. This parameter control enables room temperature forming by modifying the crystallographic texture and dislocation structure, allowing the HCP structure to deform without requiring high temperatures while maintaining excellent moldability and preventing cracking.
2Ease of manufacture
If cumulative reduction ratio is increased to improve moldability, then deformation capability is enhanced, but secondary phases segregate and form stringers causing anisotropy
Solution Approach 1:
The patent precisely controls the cumulative reduction ratio within 80-95% to optimize the balance between moldability and phase distribution. Additionally, heat treatment parameters are controlled at 300-450°C for 10-720 minutes to prevent excessive segregation of secondary phases while maintaining improved deformation capability, thus reducing anisotropy.
Solution Approach 2:
The patent creates a composite microstructure by controlling the distribution of secondary phases (Al2Ca, Al8Mn5, etc.) within the magnesium alloy matrix. Through controlled rolling and heat treatment, these phases are distributed as fine particles rather than large stringers, creating a composite structure that maintains both deformability and compositional stability.
3Manufacturing precision
If alloy composition is modified to improve limited dome height, then forming capability is enhanced, but cracks occur during transverse direction bending
Solution Approach 1:
The patent controls the cumulative reduction ratio at 80-95% and heat treatment temperature at 300-450°C to optimize the balance between limited dome height and crack resistance. This parameter control refines the crystal grain size to 5-20 μm and distributes secondary phases uniformly, enabling the material to achieve excellent forming capability without cracking during transverse direction bending.
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 solution achieves excellent moldability at room temperature with reduced anisotropy, allowing for high-strength, lightweight magnesium alloy sheets suitable for vehicle applications without cracking during bending or stretching, and enabling mass production by controlling the cumulative reduction ratio and secondary phase segregation.
Implementation Method 1
homogenization, heat-treatment, rolling, and annealing to control crystal grain size and disperse secondary phases
Implementation Method 2
annealing the rolled material
Implementation Method 3
preparing a rolled material by rolling the homogenized and heat-treated casting material; and finally annealing the rolled material, wherein, in the preparing of a rolled material, a cumulative reduction ratio is equal to or greater than 86%
Data Source
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AI summary
The present invention relates to a magnesium alloy sheet and a manufacturing method thereof. In detail, the magnesium alloy sheet includes 0.5 to 3.5 wt% of Al, 0.5 to 1.5 wt% of Zn, 0.1 to 1.0 wt% of Ca, 0.01 to 1.0 wt% of Mn, a remainder of Mg, and other inevitable impurities with respect to an entire 100 wt% of a magnesium alloy sheet, wherein an average crystal grain size of the magnesium alloy sheet is 3 to 15 µm, the magnesium alloy sheet includes a stringer, and a length of the stringer in a rolling direction (RD) is equal to or less than the maximum value of 50 µm.