Mt. Perez-prado et al., Deformation mechanisms of superplastic Al-Li 8090 alloy examined by X-ray texture measurements, MATER T JIM, 41(11), 2000, pp. 1562-1568
The texture evolution of the Al-Li alloy 8090 has been investigated in orde
r to analyze the microscopic mechanisms operative during deformation under
different conditions of temperature and strain rate. A through-thickness te
xture gradient is present in the os-received material. As will be seen, the
predominant deformation mechanisms are different in the mid layer and in t
he outer regions of the 8090 sheet alloy In the outer regions, the texture
intensity decreases with deformation and no significant changes in the main
components were observed, indicating the predominance of grain boundary sl
iding (GBS). In the mid-layer however, texture sharpens with straining and
major changes in the main texture components were detected, revealing that
crystallographic slip (CS) plays an important role in the deformation of th
is zone. CS takes place mainly in two slip systems and causes the orientati
ons to move along the B-fiber in Euler space, towards the Copper component
in longitudinal tests and towards the Brass component in transverse tests.
The comparably small ductility of the 8090 alloy with respect to other simi
lar superplastic aluminum alloys, may be due to the operation of CS in the
mid-layer.