Performance Optimization for Mechanical Properties and Corrosion Resistance of Mg-Al Rolled Alloy with Zn Nano-Coating

Abstract

Magnesium alloy castings and wrought products have many applications in the transportation industry due to their high strength-to-weight ratio. Unfortunately, the highly reactive magnesium materials are susceptible to natural deterioration; thus, the mechanical properties of magnesium alloys must be enhanced to meet the requirements of many applications, as must their chemical behavior. To solve this problem, the Mg-Al alloy was hardened mechanically by cold and warm rolling before Zn nanocoating. The rolled alloy showed a different morphology where the microstructure has deformed and refined with the fragmentation in the β-phase from 50μm for the as-received samples to about 20μm. A Zn coating layer with a thickness of approximately 23 micrometers was successfully achieved after a sputtering interval of 20 minutes, due to a longer deposition time for the zinc coating layer. The hardness has improved as deformation increased, as evidenced by a reduction in the thickness of the rolled samples. X-ray diffraction patterns show that twinning has been significantly activated in the rolled alloy compared with the as-received alloy. Geometric designs of the alloy have improved the mechanical properties and corrosion resistance of Mg alloys.