INFLUENCE OF POST-SUPERPLASTIC FORMING PRACTICES ON THE TENSILE PROPERTIES OF ALUMINUM-LITHIUM ALLOYS

The effect of thermal processing following superplastic forming on the tensile properties of aluminum-lithium alloys is addressed, The start ing materials consisted of alloys 8090, 2090, and X2095 (a Weldalite(T M) 049 variant) in the form of commercial-grade superplastic sheet. Ex perience dictates that post-forming practices aimed at a slightly unde raged T6 temper produce balanced engineering properties in these alloy s. The objective of this study was to assess the potential to use a TS -type temper by eliminating the solution heat treatment and/or cold wa ter quenching steps characteristic of T6 processing, The experimental procedures adopted ensured that the tensile properties compiled were r epresentative of the bulk material Initially, the strengthening behavi or of each alloy as a function of temper selection was established, Su bsequently, aging practices that resulted in peak strength and balance d properties were identified for the baseline T6 temper and two T5 tem pers, The implications for replacing a T6 temper with a T5-type temper , including rapid and slow cooling following forming, are discussed on the basis of the results.