New Al-Li Forgings for Aircraft Wheels

Aerospace wheels require medium strength, high fatigue performance and elevated temperature properties.  Aluminum alloys 2014-T6 and, more recently, 2040-T6 are used for forged aerospace wheels.  Alloy 2014-T6 is a medium strength alloy with good thermal stability, while the Ag containing alloy 2040-T6 offers higher static properties, improved thermal stability, improved fracture toughness and slightly better resistance to fatigue initiation than 2014-T6.  In addition to 2040-T6, Alcoa has developed a new candidate wheel alloy product which offers potential weight savings due to its lower density and higher strength compared to 2014-T6 wheels; tensile yield and compressive strength increases of 12% and 16%, respectively.  The new Al-Li alloy wheel product also offers improvements to bearing (17%), shear (7%), elevated temperature strength retention, and fracture toughness (25%).  Limited notched fatigue results indicate that the new wheel alloy offers improved performance over both 2014-T6 and 2040-T6.  Corrosion performance is comparable to most Al-Li products and will be described.