Experimental study of 2024 aluminium alloy uniaxial ratchetting under
stress-controlled cyclic loading
Abstract
A good comprehension of the uniaxial ratchetting behaviour is an
effective method to improve the reliability and the durability of 2024
Aluminium alloy components during in-service loading conditions. For
this purpose, experimental fatigue tests have been performed under
stress range control. The maximum axial deformation proved to have an
atypical oscillatory evolution which in turn has a doubly oscillatory
form. This behaviour was found to experience two scenarios consisting of
a succession of hardening and softening blocs. The interpretation of
this behaviour, which found its origin at the microscopic scale, was in
good agreement with previous experimental works performed under cyclic
TC and TT90 loadings in strain-controlled mode. Indeed, it was assumed
that this behaviour is attributed to dynamic strain ageing (DSA) due to
the repeated locking and unlocking of dislocations by the diffusive
solute atoms and precipitates during cyclic loadings.