Microhardness indentation studies of 2-4-6 trinitrotoluene

Hugh G. Gallagher, John N. Sherwood, Ranko M. Vrcelj

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The microhardness of the {001} faces of 2-4-6 trinitrotoluene crystals has been investigated using both Vickers and Knoop indentation methods. The Vickers hardness number was found to be 22.5 kg mm−2 independent of crystal orientation and perfection. At ambient temperatures (∼20 °C) the Knoop hardness number varied between 20.5 kg mm−2 and 24.0 kg mm−2 with crystal orientation. At higher temperature (50 °C) the Knoop hardness anisotropy curve retained its shape, although the overall hardness decreased by 10 %. We interpret this change as reflecting a simple temperature dependant loosening of the crystal lattice rather than any change in deformation mechanism. No variation of Knoop hardness was evident with changing load. The hard direction was [010] and the soft [100]. The dominant operative slip system was defined to be {001}[010].
Original languageEnglish
Pages (from-to)1733-1739
Number of pages7
JournalPropellants, Explosives, Pyrotechnics
Issue number11
Early online date20 Oct 2021
Publication statusPublished - 30 Nov 2021


  • mechanical properties
  • microhardness
  • TNT


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