The effect of fabrication on corrosion in aluminum 2195: Environmental and microstructural considerations

Aluminum alloys containing lithium are particularly attractive to the aerospace structural designer. Lithium's density is only 0.53 g/cc, thus an addition of one weight percent lithium not only increases yield strength, but decreases the density by almost three percent while increasing the modulus by over six percent. The fact that lithium improves these physical properties simultaneously has led to intense study and development of the alloy system. Heretofore, problems in large scale alloy production have retarded commercial development. During the last fifteen years, advances in production technology have rekindled interest in Al-Li alloys, and aluminum suppliers have developed many candidate aerospace materials. However, if these alloys are to be employed successfully, a more complete understanding of their nonequilibrium metallurgy is required. Peel and Starke have each pointed out that an understanding of the weldability of these alloys is a critical step in their implementation. This study addresses the critical lack of information on the environmental compatibility of welded Al 2195 components. Corrosion data for these systems is incomplete, particularly for welded materials exposed to sea water or sea water condensate.