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Experimental and computational analysis of toughness anisotropy in an AA2139 Al-alloy for aerospace applications
Last modified: 2013-05-03
Abstract
Fracture toughness anisotropy of AA2139 (Al-Cu-Mg) in T351 and T8 conditions
has been investigated via mechanical testing of smooth and notched specimens of
different geometries, loaded in the rolling direction (L) or in the transverse
direction (T). Fracture mechanisms were investigated via SEM and synchrotron
radiation computed tomography (SRCT). Contributions to failure anisotropy are
identified with: (i) anisotropic initial void shape and growth, (ii) plastic behaviour
including isotropic/kinematic hardening and plastic anisotropy, and (iii)
nucleation at a 2nd population of 2nd phase particles leading to coalescence via
narrow crack regions. A model based in part on the Gurson-Tvergaard-
Needleman approach is constructed to describe and predict deformation
behaviour, crack propagation and, in particular, toughness anisotropy. Model
parameters are fitted using microstructural data and data on deformation and
crack propagation for a range of small test samples. Its transferability has been
shown by simulating tests of large M(T) samples.
has been investigated via mechanical testing of smooth and notched specimens of
different geometries, loaded in the rolling direction (L) or in the transverse
direction (T). Fracture mechanisms were investigated via SEM and synchrotron
radiation computed tomography (SRCT). Contributions to failure anisotropy are
identified with: (i) anisotropic initial void shape and growth, (ii) plastic behaviour
including isotropic/kinematic hardening and plastic anisotropy, and (iii)
nucleation at a 2nd population of 2nd phase particles leading to coalescence via
narrow crack regions. A model based in part on the Gurson-Tvergaard-
Needleman approach is constructed to describe and predict deformation
behaviour, crack propagation and, in particular, toughness anisotropy. Model
parameters are fitted using microstructural data and data on deformation and
crack propagation for a range of small test samples. Its transferability has been
shown by simulating tests of large M(T) samples.
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