Introduction to Aerospace Materials

10

Magnesium alloys for aerospace structures

10.1 Introduction

Magnesium is the lightest of all the metals used in aircraft. The density of magnesium is only 1.7 g cm⁻³, which is much lower than the specific gravity of the other aerospace structural metals: aluminium (2.7 g cm⁻³), titanium (4.6 g cm⁻³), steel (7.8 g cm⁻³). Only carbon-fibre composite material has a density (~ 1.7 g/cm³) that is similar to magnesium. Magnesium alloys have lower stiffness and strength properties than the aerospace structural materials, but because of its low density the specific properties are similar. However, there are several problems with using magnesium alloys, including higher cost and lower strength, fatigue life, ductility, toughness and creep resistant ...