Damage evolution in freeze cast metal/ceramic composites exhibiting lamellar microstructures
Journal Title: Frattura ed Integrità Strutturale - Year 2015, Vol 9, Issue 33
Abstract
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.
Authors and Affiliations
C. Simpson, P. Withers, T. Lowe, S. Roy, A. Wanner
Keywords
Related Articles
- EP ID EP111399
- DOI 10.3221/IGF-ESIS.33.17
- Views 47
- Downloads 0
Study of drilling muds on the anti-erosion property of a fluidic amplifier in directional drilling
Due to some drawbacks of conventional drilling methods and drilling tools, the application of hydraulic hammers with a fluidic amplifier have been extensively popularized since its emergence in recent years....
A data fusion based approach for damagedetection in linear systems
The aim of the present paper is to propose innovative approaches able to improve the capability ofclassical damage indicators in detecting the damage position in linear systems. In particular, starting fromclassica...
Designing aluminium friction stir welded joints against multiaxial fatigue
The present paper investigates the accuracy of the Modified Wöhler Curve Method (MWCM) in estimating multiaxial fatigue strength of aluminium friction stir (FS) welded joints. Having developed a bespoke joini...
Investigation of crack paths in natural fibre-reinforced composites
Nowadays, fibre-reinforced composite materials are widely used in many fields, e.g. automotive and aerospace. Natural fibres such as flax and hemp provide good density specific mechanical properties. Additionally...
Elementi di interfaccia per l’analisi di strutture murarie
The present paper deals with the modelling of the mechanical behaviour of masonry elements regarded as heterogeneous systems, made of mortar, bricks and interfaces. Thus, the adopted computational strategy consists in mo...