MICROSTRUCTURE AND PROPERTIES OF A WELDED AL-CU-LI ALLOY

Aluminum-lithium alloys are being considered for several applications that take advantage of the attractive combination of properties in these alloys including low density, high modulus, and high strength. A recently introduced Al-Cu-Li alloy, Weldalite(TM) 049(1), has the unique combination of ultrahigh strength and good weldability. In this investigation, the mechanical properties of fusion weldments of Weldalite 049 made using Li-containing filler metals are examined. Hardness, tensile tests at ambient and cryogenic temperatures, fractography, and microstructure were evaluated for weldments made with three ternary Al-Cu-Li filler metals and commercial Al-Cu filler metal 2319. The response to heat treatment of these weldments was also investigated. The results suggest that the use of Li-containing filler metals can produce weldments that are free from hot-tearing problems and possess good mechanical properties.