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Development Of pressureless sintered silicon carbide-boron carbide composites for armour applications.

Williams, T. (2016) Development Of pressureless sintered silicon carbide-boron carbide composites for armour applications. Doctoral thesis, University of Surrey.

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Abstract

Ceramic armour must offer protection against armour piercing threats at low weight and affordable cost. As a possible means of improving armour, a range of SiC-B4C composites have been produced and characterised. The degree of contact between the two phases has been quantified and shown to have a strong effect on the densification and microstructure in these materials. This understanding has enabled independent variation of microstructural parameters which are normally interrelated. These were; porosity, SiC:B4C mass ratio, B4C distribution in a SiC matrix and SiC grain size distribution. To assess effects of each of these parameters on ballistic performance V50 testing was carried out, using 7.62 mm armour piercing rounds. The amount of porosity is shown to have a slight effect on V50 and a marked effect on scatter in V50. The pore size distribution is also shown to be important; across a range of pairs of materials with similar total pore volumes but differing pore size distributions, larger pores consistently give lower V50. SiC:B4C mass ratio does not seem to greatly affect V50, potentially allowing application specific cost/weight balances at constant protection level. B4C distribution has a strong effect. In general, for B4C features with diameters ranging from 1 m to 100 m, the coarser features performed better. Using coarse B4C particles in a SiC matrix, a V50 of approximately 980 ± 20 m s-1 at a density of 3.00 g cm-3 was achieved reproducibly. This material is preferred due to a combination of relatively lower cost, reduced density and repeatability. Knoop indentation has been used to derive possible merit indices which could potentially be used to rank ballistic materials. These includes analysis of failure probability of indents and the indentation size effect. A preliminary study indicates ballistic impacts may affect SiC polytype composition.

Item Type: Thesis (Doctoral)
Subjects : Ceramic Armour, Sintering, Ballistics,
Divisions : Theses
Authors :
AuthorsEmailORCID
Williams, T.tomwilliams34@gmail.comorcid.org/0000-0002-8910-3211
Date : 29 April 2016
Funders : EPSRC, DSTL
Copyright Disclaimer : Copyright (c) Tom Williams 2015
Contributors :
ContributionNameEmailORCID
Thesis supervisorYeomans, J.j.yeomans@surrey.ac.ukUNSPECIFIED
Thesis supervisorSmith, P.p.smith@surrey.ac.ukUNSPECIFIED
Thesis supervisorHampson, C.chris.hampson@morganplc.comUNSPECIFIED
Thesis supervisorHeaton, A.aheaton@mail.dstl.gov.ukUNSPECIFIED
Uncontrolled Keywords : Ceramic Composites, Materials Science, Silicon carbide, boron carbide
Depositing User : Tom Williams
Date Deposited : 13 May 2016 08:42
Last Modified : 13 May 2016 08:42
URI: http://epubs.surrey.ac.uk/id/eprint/810348

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