Damage and loading rate effects on the microfailure behaviour of Al 2O3-ceramics studied by SEM

Kytopoulos, VN; Papadopoulos, GA; Sadowski, T

dc.contributor.author	Kytopoulos, VN	en
dc.contributor.author	Papadopoulos, GA	en
dc.contributor.author	Sadowski, T	en
dc.date.accessioned	2014-03-01T01:23:47Z
dc.date.available	2014-03-01T01:23:47Z
dc.date.issued	2006	en
dc.identifier.issn	0022-2461	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/17135
dc.subject	Electron Probe Microanalysis	en
dc.subject	Energy Dissipation	en
dc.subject	Energy Requirement	en
dc.subject	Scanning Electron Microscopy	en
dc.subject	X Rays	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.other	Alumina	en
dc.subject.other	Computer simulation	en
dc.subject.other	Failure analysis	en
dc.subject.other	Microcracking	en
dc.subject.other	Scanning electron microscopy	en
dc.subject.other	Surface roughness	en
dc.subject.other	X ray analysis	en
dc.subject.other	Fractographic roughness	en
dc.subject.other	Fractographical images	en
dc.subject.other	Microfractographic features	en
dc.subject.other	Ceramic materials	en
dc.title	Damage and loading rate effects on the microfailure behaviour of Al 2O3-ceramics studied by SEM	en
heal.type	journalArticle	en
heal.identifier.primary	10.1007/s10853-006-3638-z	en
heal.identifier.secondary	http://dx.doi.org/10.1007/s10853-006-3638-z	en
heal.language	English	en
heal.publicationDate	2006	en
heal.abstract	A scanning electron microscopy (SEM)-X-ray combined experimental approach to qualitative and semi-quantitative characterization of microfailure behaviour of an Al2O3-ceramic material in terms of induced damage is presented. The qualitative approach was based on representative fractographical images and data obtained by SEM whereas the semi-quantitative approach was based on a new technique of the X-ray electron probe microanalysis (X-ray EPMA) capable to detect the localized subsurface damage. The damage was induced by a simple rotary notch-cutting procedure where the associated damage parameters can be controlled by the cutting rate. By correlating certain characteristic macro- and microfractographic features/patterns with well-known microfailure mechanisms it was possible to make qualitatively, in an indirect way, evident the existence of induced damage which was assumed to be ideal brittle having only microcracking component. In the same correlating way the stimulating effect of internal pores on the damage development was deduced. Observed loading rate effects on the fractographic behaviour expressed by changes in fracture roughness and micromorphology were attributed to pore-assisted microcracking linkage. Low porosity under high loading rates tends to lower the fractographic roughness, a fact which can be related with a reduction in the ability of energy dissipation. On the other hand, high porosity under increasing loading rates leads to non observable changes in the fractographic roughness, a fact which is indicative of corresponding no appreciable changes in the dissipative character of the material. The measured local damage distribution ahead of the notch-tip shows a monotonic increasing of damaging effects toward the tip. By means of this distribution the total or average damage degree and process zone length ahead of the notch-tip were evaluated. The increase of these two damage parameters is not proportional to the increase in the cutting speed i.e. the rate of damage development. Finally, by assuming brittle damage an experimental approaching procedure for the estimation of the induced energy required for the microcracking damage was proposed. (c) 2006 Springer Science + Business Media, Inc.	en
heal.publisher	SPRINGER	en
heal.journalName	Journal of Materials Science	en
dc.identifier.doi	10.1007/s10853-006-3638-z	en
dc.identifier.isi	ISI:000236968200033	en
dc.identifier.volume	41	en
dc.identifier.issue	7	en
dc.identifier.spage	2121	en
dc.identifier.epage	2131	en