High-strength/high-ductility magnesium sheet alloy for room-temperature forming

A new magnesium alloy designed using computational thermodynamic and kinetic models, which possesses optimal mechanical and formability performance suitable for industrial applications

The Need

Magnesium (Mg), the lightest structural metal, and its alloys, with their high specific strength and low density, are promising lightweight materials for industrial applications in automotive, aerospace, and electronic sectors. A 2019 report by Business Communications Company (BCC) Research highlights vehicle light-weighting with Magnesium as a $4.1 billion USD global market and finds that this is expected to grow at a compound annual growth rate (CAGR) of 6.9% to 5.7 billion USD by 2024 (EGY166A). Currently, however, there are limitations on the applications of Mg alloys when compared to commercial aluminum alloys and steels. These limitations are largely based on the low strength, poor ductility, and poor formability at room temperature associated with Mg alloys currently available in the market. There is, therefore, an urgent need to improve the mechanical performance of Mg sheet alloys at room temperature, especially for high-volume industrial applications such as the automotive market.

The Technology

To address this unmet need, the Light Metals and Manufacturing Research Laboratory led by Professor Alan A. Luo at The Ohio State University has developed a new magnesium alloy, ZAXEM11100 (Mg-1Zn-1Al-0.3Ca-0.2Ce-0.4Mn). The new alloy possesses a better combination of tensile yield strength (245 MPa), elongation (29%) and formability (Erichson index 7.7mm from 20mm cup test) at room temperature, compared with commercial alloys or other experimental alloys reported in literature. CALculation of PHAse Diagram (CALPHAD) modeling was used to optimize the addition of alloying elements by controlling solute concentration and precipitate in the Mg matrix. Additionally, CALPHAD and kinetic modeling was used to develop a new homogenization process for the new alloy which achieves complete dissolution of alloying elements without incipient melting. These computational thermodynamic and kinetic models were successfully combined to create a new Mg alloy design with excellent strength and ductility as well as the ability to be stamped (press-formed) at room temperature. The researchers tested their new alloy via a series of carefully designed tensile and Erichson cupping (20mm) tests.

Commercial Applications

  • Automotive
  • Aerospace
  • Electronics

Benefits/Advantages

  • Low cost because of room-temperature press-forming process and inexpensive alloying elements
  • Lightweight magnesium alloys compared with commercial aluminum alloys/steels
  • Excellent combination of mechanical properties and formability surpassing those of the existing magnesium sheet alloys reported so far.

Research Interest

The Light Metals and Manufacturing Research Laboratory at The Ohio State University is led by Professor Alan A. Luo. The lab uses computational thermodynamics and the CALPHAD (CALculation of PHAse Diagrams) modeling approaches to develop advanced lightweight materials (Al, Mg, Ti alloys, high entropy alloys and metal matrix composites) with superior properties. They specialize in developing innovative manufacturing processes, including casting, forming, and multi-material manufacturing, for metals by incorporating process simulation and multi-scale microstructure modeling. Prof. Luo is an elected Fellow of ASM International (American Society of Metals) and SAE International (Society for Automotive Engineers).

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