Superplastic properties of an Al2.4Mg1.8Li0.5Sc alloy

摘要: There is a need in the aerospace industry for structural, superplastic aluminum alloys that are formable at strain-rates greater than 10[sup [minus]3] s[sup [minus]1] order economic benefits of forming to be realized. The standard, alloy 7475, which has an optimum strain-rate near [minus]4] [minus]1]. Thus, research been focused on modifying microstructures wrought Al-Li such as 2090 and 8090 into superplastically (SPF) with improved properties, but results have not completely successful. Superplastic high strengths produced from Al-Mg-Sc system. These strengthened by thermomechanical processing (1) precipitates small, coherent Al[sub 3]Sc particles (2) increases dislocation density material. Mg solid solution improves work hardening capability these alloys. Because carried out relatively temperatures, recovery processes eliminate strengthening resulting rolling overage precipitates. additional precipitation required make attractive use applications. Lithium provides most promising choice since it forms ordered precipitate [delta][prime] (Al[sub 3]Li),more » lowers density, stiffness In addition, low concentrations, Li should SPF temperatures little effect formability This led Al-Mg-Li-Sc paper describes preliminary high-temperature tensile relates them other Al alloys.« less