The damage evolution in a single domain aluminium/alumina freeze-cast composite has been examined using 3D X-ray computed tomography (CT). A single domain was extracted and loaded incrementally at an orientation of 45° to the lamellae, with the damage being assessed after each of eight compressive loading steps. Prior to loading, significant damage was observed at the metal-ceramic interface – this is thought to have formed during machining and can be ascribed to weak interfacial bonding associated with the Cu coating applied to the ceramic preform prior to metal infiltration. Further interfacial damage was seen to initiate after loading to 170MPa and to develop with each subsequent load step. Damage was also observed in the ceramic lamellae, with a series of parallel cracks forming across the alumina, perpendicular to the domain orientation.
These sets of parallel, intra-lamellae cracks were closely spaced, but initiated independently, with coalescence
only occurring at higher loads. Both the interfacial and intra-lamellae cracking initiated after loading to 170MPa,
with the intra-lamellae cracks propagating into the metal matrix after loading to 240MPa. The cracks in the ceramic lamellae were found to form and develop independent of the interfacial cracks, with discrete crack
paths and morphologies being observed in each case. Despite this, the underlying driving force was the same
for each damage mode, with crack propagation being driven by an elastic-plastic mismatch between the metal
matrix and ceramic lamellae.
How to Cite
Authors are allowed to retain both the copyright and the publishing rights of their articles without restrictions.
Open Access Statement
Frattura ed Integrità Strutturale (Fracture and Structural Integrity, F&SI) is an open-access journal which means that all content is freely available without charge to the user or his/her institution. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles in this journal without asking prior permission from the publisher or the author. This is in accordance with the DOAI definition of open access.
F&SI operates under the Creative Commons Licence Attribution 4.0 International (CC-BY 4.0). This allows to copy and redistribute the material in any medium or format, to remix, transform and build upon the material for any purpose, even commercially, but giving appropriate credit and providing a link to the license and indicating if changes were made.