CHARACTERIZATION OF THE SCC BEHAVIOR OF 8090-AL-LI ALLOY BY MEANS OF THE SLOW-STRAIN-RATE TECHNIQUE

Aluminium-lithium alloys possess a high resistance to stress corrosion cracking (SCC) compared with more conventional alloys. With tradition al testing techniques and in conventional media some Al-Li alloys, suc h as 8090, show no susceptibility to SCC owing to the fact that such t echniques and solutions are not appropriate for determining their beha viour. The slow-strain-rate technique makes it possible to detect the susceptibility to SCC in systems for which it cannot be detected with other testing techniques or takes much longer to detect. In the litera ture there are no unanimous criteria for establishing whether this tec hnique permits characterization of the SCC behaviour of 8090-T8171 she et in the L and LT directions, when used in standard solutions and at strain rates of between 10(-7) and 10(-4). In this work, a strain rate value has been found for which the fracture of alloy 8090-T8171, in 1 M NaCl + 0.3% H2O2, occurs as a consequence of an SCC process. Higher and lower strain rates lead to failure as a result of other mechanism s. (C) 1997 Elsevier Science Ltd.