Achieving Strength and Fracture Toughness in Heavy Section Aluminum Rolled Ring Forgings

Aluminum rolled ring forgings used for aerospace applications require excellent combinations of tensile strength and fracture toughness.  AMS 4144F (Cu-Mn-Zr-V-Ti) grade is employed in some of these applications.  The AMS specification tensile requirements of 52 to 54 ksi (UTS) apply to forgings up to 6 inch nominal thickness at time of heat treat.  In addition to these tensile requirements, plane strain fracture toughness values greater than 20 ksi square root inch are also required. 

By employing specific chemical composition controls, as well as specialized thermo-mechanical processing, plane strain fracture toughness (KIC) values exceeding 25 KSI square root inch are achieved, while maintaining the required tensile properties.  Careful controls and coordination between mechanical stress relieving, solution annealing, and precipitation age cycles is critical to achieving these results