Microstructure and Texture Evolutions During Deep Drawing of Mg-Al-Mn Sheets at Elevated Temperatures

Area of Science:

• Materials Science
• Metallurgy
• Mechanical Engineering

Background:

• Magnesium alloys are crucial for lightweight applications.
• Understanding microstructure evolution during forming is key to optimizing properties.
• Deep drawing at elevated temperatures presents unique challenges for magnesium alloys.

Purpose of the Study:

• To investigate the deep drawability of ingot-casted versus twin-roll casted Mg-Al-Mn sheets.
• To analyze the microstructure and texture evolution during elevated temperature deep drawing.
• To compare the mechanical properties and formability of the two casting methods.

Main Methods:

• Deep drawing experiments at temperatures from 225°C to 350°C and deformation rates of 30-50 mm/min.
• Transmission Electron Microscopy (TEM) for precipitate analysis.
• Electron Backscatter Diffraction (EBSD) for microstructure and texture analysis.

Main Results:

• Twin-roll casted sheets had finer grains and weaker basal intensity but better room temperature strength.
• Ingot-casted sheets showed superior elongation at elevated temperatures and better overall deep drawability.
• Increased deformation rate promoted tensile twins, while increased temperature activated non-basal slips and dynamic recrystallization (DRX).

Conclusions:

• Ingot-casted Mg-Al-Mn sheets are more suitable for high-temperature deep drawing applications.
• Tensile twins and non-basal slips are critical mechanisms contributing to DRX and formability.
• Casting method significantly influences microstructure, texture, and subsequent formability of magnesium sheets.