Machineable graphene toughened boron carbide nanocomposite armour (MaGiC) for lightweight armour applications

Kenny, Jonathan (2019). Machineable graphene toughened boron carbide nanocomposite armour (MaGiC) for lightweight armour applications. University of Birmingham. Ph.D.

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Abstract

In this study, a lightweight ceramic nanocomposite made from boron carbide and reduced graphene oxide (rGO) for armour applications was both produced and tested. This was done as a means of both mitigating the extent of shock-induced amorphisation that takes place to the material upon impact by armour piercing rounds. To do this, samples were produced from commercially sourced and low temperature synthesised (LTS) boron carbide. Elemental analysis (EA) results from flash combustion and x-ray diffraction (XRD) testing confirmed that the LTS material featured a lower residual carbon content (21.3 wt.% C) than its commercial grade counterpart (22.4 wt.% C).

These materials were then blended with 0-9wt.% GO in aqueous suspensions before filtration and sintering. Raman spectroscopy identified the 1\(^{st}\) and 2\(^{nd}\) order scattering modes of nano-perforated graphene edges within the materials microstructure. These were centred at 1143 cm\(^{-1}\) and 1210 cm\(^{-1}\), as well as 1452 cm\(^{-1}\) and 1531 cm\(^{-1}\) respectively. Raman spectroscopy mapping was further able to determine a lower degree of amorphisation in the samples that had 2 wt.% GO added to them, as opposed to the pure boron carbide.

Vickers hardness testing (9.81N load) revealed that the pure LTS material had a higher average hardness than its commercial grade counterpart (37.8GPa and 32.5GPa). By increasing the GO contents of both samples, not only did their respective hardness values decrease, but so too did their Young’s moduli (the latter tested via nanoindentation using a Berkovitch indenter under a 20mN load). Furthermore, these alterations did not lead to any noticeable change in either radial crack deflection or blunting within the samples. It was also possible to cleanly cut both the pure and the 2 wt.% GO boron carbide samples using electric arc discharge machining (EDM) under low power and feed rate settings.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):