A fan blade comprises an airfoil portion and a sheath portion. The sheath portion has a sheath head section, a first sheath flank, and a second sheath flank, both flanks extending chordwise from the forward sheath section. The sheath portion is bonded to the airfoil portion such that the sheath head section covers the forward airfoil edge, defining a blade leading edge. The first sheath flank covers a portion of the first airfoil surface proximate the airfoil forward edge, jointly defining a blade suction surface. The second sheath flank covers a portion of the second airfoil surface proximate the airfoil forward edge, jointly defining a blade pressure surface. The first metallic material is an aluminum alloy containing between about 0.5 wt% and about 3.0 wt% of lithium.