Thermal stability of Al−Li alloys

Abstract

Modern passenger and cargo planes are designed for long-term service of at least thirty years. Stability of the properties of the structural materials used in planes over their entire life is a necessary requirement. The main structural material for a passenger plane is high-strength aluminum alloys, of which are AI -Li alloys the most promising. The present paper is devoted to Ai -Li alloys and concerns the nature of the thermal stability, its dependence on various structural factors, and possible ways. of stabilizing the properties.

A review of manufacturing processes, mechanical properties and precipitations for aluminum lithium alloys used in aeronautic applications

“…as it is seen in Table 1 , the 3rd contains lower amounts of Lithium (<2%) and an important Cu/Li ratio compared to the 2nd generation alloys [ 23 ] . It was noted that decreasing lithium amounts can positively influence the thermal stability and toughness of aluminum lithium alloys [ 14 , 24 , 25 ] (see Fig. 1 ).…”

Thermal Stability of Aluminum Alloys

“…A room temperature exposure of some aluminum alloys may result in natural aging, i.e., slight movements of solute atoms in the matrix, which modifies the material properties [ 58 ]. Aging of Al−Li alloys results in decomposition of solid solution of Li in Al and precipitation of Al 3 Li [ 59 ], which may lead to embrittlement during the long-term operation [ 60 , 61 ].…”

“… Tensile property change during long-term aging of 2nd generation Al−Li AA1464 alloys at 85 °C, showing an increase in strength and reduction in ductility ( a ) [ 61 ] and strengthening precipitates in third generation Al−Li alloys ( b ) [ 62 ]. …”