TATB-based explosives are known to undergo irreversible thermal expansion after single or multiple thermal cycles. This phenomenon has significant implications for mechanical properties and shock initiation behavior. Researchers have concluded that the irreversibility arises due to binder-crystal interactions, and/or from damage within individual crystals. Here, our aim was to develop a clearer picture of the damage length scale that leads to irreversible growth. To do so, we rapidly heated and cooled a PBX 9502 sample to 200 C and observed the resulting material with dye intrusion poresimmetry, scanning electron microscopy, small angle neutron scattering and Raman spectroscopy. There was clear evidence of mesoscale damage on a length scale of 1 micron or less. There was also indirect evidence that intra-crystalline damage did not occur, although that evidence was not conclusive.
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