Fatigue of Al-Li alloys: mechanical properties, microstructure (TEM and SEM) and strain localization

The fatigue behaviour of two binary AI-Li alloys (A, solid solution; B, containing δ′ precipitates) is studied by macroscopic fatigue tests, and microscopic (SEM and STEM) observations. Two types of strain localization are found, appearing as two types of slip band in SEM, and as two types of substructure in TEM. These characteristics are ascribed to strain localization processes governed by strain amplitude for the former and strain rate for the latter.