The present paper shows results from an investigation of the mechanical behavior of single crystals of the energetic material pentaerythritoltetranitrate (PETN) using a nano-indentation technique. The indentation tests have been performed on the crystal face (110), using a spherical tip. The load displacement curves have been analyzed in order to extract the mechanical properties. The modulus of the PETN single crystal was found to decrease as indentation depth increases and become independent of displacement depth when the indentation depth is greater than 200nm. The high modulus at low indentation depths is attributed to the high pressure between the probe and crystal surface when the contact area is very small. The compression stresses lead to a decrease in intermolecular distances that cause the increase in modulus at low indentation depths. The modulus determined in the depth independent region is in agreement with literature values.
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