Nanomechanical behavior of energetic solids

The mechanical response of crystalline energetic solids to force loading is known to play a role in their thermal decomposition, and also contributes to the overall mechanical behavior of the composite solid propellant. We are currently studying the response of energetic crystals to near surface loading by nanoindentation. Most of the previous work on characterization of mechanical properties of energetic solids has been performed on large single crystals (> 1 cm edge length), which are significantly greater in size than those typically used in solid propellant formulations (~ 2 - 600 micrometers). Our current work is focused on the mechanical behavior of formulation size ammonium perchlorate (AP) crystals. We seek to develop an understanding of the conditions at the onset of plastic deformation, the operative slip systems and the resulting surface material pile-up and cracking.

Collaborators:

L. De Luca, Politecnico di Milano

Relevant publication:

Lucca, D.A., Klopfstein, M.J., Mejia, O.R., Rossettini, L. and De Luca, L., "Investigation of Ammonium Perchlorate by Nanoindentation", Materials Science and Technology, 22 No. 4, (2006) 396-401.

Lucca, D.A., Klopfstein, M.J., Mejia, O.R., Rossettini, L. and De Luca, L., "Investigation of the Near Surface Mechanical Properties of Ammonium Perchlorate Using Nanoindentation", Edited Book of the 9-IWCP, Novel Energetic Materials and Applications, Lerici, La Spezia, Italy, (2004), 31.